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Embedded System Microcontroller Interactive Course using BASCOM-AVR - Lecture10

AL-AWAIL for Electronic Engineering, profile picture
AL-AWAIL for Electronic Engineering

This document provides instructions for practicing serial communication using an RS485 interface. It explains how to connect an RS485 transceiver module to two microcontrollers and send data between them. The microcontrollers will transmit a "1" or "0" depending on whether voltage VA is greater than or less than voltage VB. This demonstrates half-duplex serial communication using differential signaling as required by the RS485 standard to communicate over long distances.

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   ‫ﺍﻟﺘﺠﺎﺭﺏ ﺍﻟﻌﻤﻠﻴﺔ‬     Programming Embedded Systems Microcontroller You Can Practice Microcontroller Programming Easily Now! WALID BALID, Tuesday, December 15, 2009
Practical Class 10 Programming Microcontrollers Exp.28:Serial Communications RS485 RS485     RS485  RS485           RS485     A,B   VA>VB “1” VA<VB  “1”“0”    RS485 B A                      RS485 RS485 ST TI MAXIM LTC ST485 SN75176 MAX485 LTC485 :RS485 Faculty of Electrical and Electronic Eng. 213 Automatic Control & Automation Dept.
      RS485 SPECIFICATIONS RS232 RS423 RS422 RS485 Mode of Operation SINGLE-ENDED SINGLE-ENDED Differential Differential Total Number of Drivers and 1DRIVER 1DRIVER 1DRIVER 32DRIVER Receivers on One Line 1RECVR 10RECVR 10RECVR 32RECVR Maximum Cable Length 50 FT 4000 FT 4000 FT 4000 FT 10Mb/s 10Mb/s Maximum Data Rate 20kb/s 100kb/s 100Kb/s 100Kb/s Maximum Driver Output Voltage ±25V ±6V -0.25V to +6V -7V to +12V Driver Output Signal Loaded ±5V to ±15V ±3.6V ±2.0V ±1.5V Level (Loaded Min.) Driver Output Signal Unloaded ±25V ±6V ±6V ±6V Level (Unloaded Max) Driver Load Impedance (Ohms) 3k to 7k >=450 100 54 Max. Driver Current in Power On N/A N/A N/A ±100uA High Z State Max. Driver Current in Power Off ±6mA @ ±2v ±100uA ±100uA ±100uA High Z State Slew Rate (Max.) 30V/µS Adjustable N/A N/A Receiver Input Voltage Range ±15V ±12V -10V to +10V -7V to +12V Receiver Input Sensitivity ±3V ±200mV ±200mV ±200mV Receiver Input Resistance (Ohms) 3k to 7k 4k min 4k min >=12k                   RS485                         214 
Practical Class 10 Programming Microcontrollers  RS485 B  A       15Meter   Backbone with StubsDaisy Chain    RS485    Faculty of Electrical and Electronic Eng. 215 Automatic Control & Automation Dept.
        RS485   PASSIVE DUPLEX CONTROL (AUTOMATIC ) ü ACTIVE DUPLEX CONTROL (RTS Pin ) ü RS485    RO, DI      Passive Duplex   ü  DE/RE Driver      No data to send  §              “1” Idle Master sends a request  §      Start Bit        Stop Bit              Check sum  Idle  216 
Practical Class 10 Programming Microcontrollers Slave sends a response  §           add = 07        RS485 Driver Active Duplex ü   RTS Control            No data to send     § RTS          “1”     Master sends a request  §      Start Bit        Stop Bit Check sum  Idle Faculty of Electrical and Electronic Eng. 217 Automatic Control & Automation Dept.
     Slave sends a response   add = 07       RS232  Advantages  Disadvantages        ü System-to-System       ×    Chip-2-Chip  1200 ü .Chip-2-Sensor   100kb/s RS485<>TTL ×   ü         ü  :RS485MODBUS          MODEBUS   Multi Master/Slave                   Master Device   MODEBUS          Slave Device  Slave DeviceMaster DeviceQueryMODEBUS Slave Function Start Start Byte Count Data CRC Address Code Address Hi Address Lo  218 
Practical Class 10 Programming Microcontrollers Slave Function Byte Start Data CRC Address Code Count Address Stream CRC Low CRC Hi 1 byte 1 byte 1 byte 2 byte 0 ~ 252 byte 1~2 byte 1~252Slave Address • Function code • Byte Count • Start Address • 255 byte maxData Stream •  Cyclic Redundancy CheckCRC •  Inter-frame-time              t3.5     Data  t1.5      Inter-character time-out (t1.5) = 750μs Inter-frame delay (t3.5) = 1.750ms Faculty of Electrical and Electronic Eng. 219 Automatic Control & Automation Dept.
     70Byte9600bps   Slave address   70 ×8 = 560 × 1000 = .    58ms                .t3.5= 1.75ms   Start Master Set Control Pin Waitms 10 Send Data Frame Reset Control Pin Waitms 100 End  220 
Practical Class 10 Programming Microcontrollers   Start Slave NO UART INT Yes Byte1 is Disable UART Slave ADD Wait 90ms NO Yes Get the data at the 90ms Passed? UART Interface (MSB First, LSB Last ) Yes Enable UART NO Check Count Check CRC Programming YES OK Ignore Data Set Data Value End  MasterSlaveResponceMODEBUS     Slave                               Slave Function Byte CRC Address Code Count CRC Low CRC Hi 1 byte 1 byte 1 byte 1~2 byte Slave  CRC Faculty of Electrical and Electronic Eng. 221 Automatic Control & Automation Dept.
      RS485| Full-DuplexHalf-DuplexRS485             RS485     222 
Practical Class 10 Programming Microcontrollers  UART<>RS458 Max485           Config Print0 = Porte.2 , Mode = Set .RS485 “DE”“1”Config Print0  “0”“DE” “DE”   Faculty of Electrical and Electronic Eng. 223 Automatic Control & Automation Dept.
      Microcontroller is Master, PC is Slave $regfile = "m128def.dat" $crystal = 8000000   $baud = 9600 '------------------ Config Print0 = Porte.2 , Mode = Set  Config Pine.2 = Output  DE Config Pine.4 = Input   Key1 Alias Pine.4 Porte.4 = 1 '------------------   Dim Msg As String * 100 '------------------ Do Debounce Key1 , 0 , Sendall , Sub Loop End '------------------ Sendall: Print "This is RS485 Test Program" Print "RS458 Protocol Done Based-on MAX485" Print "University of Aleppo - Syria" Print "Faculty of Alectrical & Electronic Engineering"   Print "Control Department" Print "Fourth Year Students" Print "Computer Aided Design Session" Print "Unfutunality This Was The Last Session Lab" Print "2nd Semester" Print "See You Next Semester Guys ;)" Print "Kindest Regards" Print "Walid BALID" Print ":) :) :) :) :) :) :) :) :) :) :) :)" Wait 1 Return                224 
Practical Class 10 Programming Microcontrollers  Microcontroller is Slave, PC is Master $regfile = "m128def.dat" $crystal = 8000000   $baud = 9600 '-------------------------  DE Config Porte.2 = Output Config Print = Porte.2 , Mode = Reset   Open "comd.3:9600,8,n,1" For Output As #1  UART Open "comd.2:9600,8,n,1" For Input As #2   Config Serialin = Buffered , Size = 250   Enable Interrupts '-------------------------   Dim Msg As String * 250 '------------------------ Do   If Ischarwaiting() = 1 Then Input Msg UART Print #1 , Msg  End If Loop  UART End                                       Faculty of Electrical and Electronic Eng. 225 Automatic Control & Automation Dept.
      RS232<>RS458 RS232<>RS458 RS232<>RS458          226 
Practical Class 10 Programming Microcontrollers  RS232<>UART<>RS458       RS232<>UART<>RS458        Max232 UART Max485 UART    RS232<>UART<>RS458 Faculty of Electrical and Electronic Eng. 227 Automatic Control & Automation Dept.
     Exp.29:Serial Communications USB USB     USB            USB     USB  USB  480Mb/s ü  . Plug & Play  ü   ü  127 ü   :USB  USB 1.0 & USB 1.1 & USB 2.0& USB 3.0USB  USB 1.01.5 Mbits/s Low Speed § USB 1.112 Mbits/s Full Speed § .USB 2.0480 Mbits/s High Speed §  .USB 3.04800 Mbits/s  §        USB  ”Host Controlled”  USB        )                USB  228 
Practical Class 10 Programming Microcontrollers ”On-The-Go”    USB   ü  ü  HUB USB       Plug& Play  Plug & Play USB   USB      VID, PID   USB   Faculty of Electrical and Electronic Eng. 229 Automatic Control & Automation Dept.
      USB   USB  A §  B §     D- & D++5v & GNDUSB  VCC1   D-2   D+3     GND4   '1'       D+&D-  USB    D-  '0' D+ '1'    :(Non Return to Zero Invert) NRZI NRZIUSB   '0' '1''0'  '1'    '1'    230 
Practical Class 10 Programming Microcontrollers       USB  D- D+ D- .1 D+ .2  .3      USB  USB  USB                 USB Device USB  USB Function Host Controller IC USB  USB  USBUSB Function          USB Function  Endpoint   EndpointUSB Function  InOut Faculty of Electrical and Electronic Eng. 231 Automatic Control & Automation Dept.
      USB    EP2 In  USB Function        USB1  EP1 In [Addr : 2] [Endpoint : EP1] [In]  USB1 PipePipe  EP0 In & EP0 Out  Pipe0  Pipe        Pipe   Control Transfers §  232 
Practical Class 10 Programming Microcontrollers Interrupt Transfers § Isochronous Transfers § Bulk Transfers §  USB          Frame     USB    1ms  USB1.1, USB2.0  125µs Transaction                    Token Packet   In Token  Synchronization .1    Packet Identity PID .2    128Address .3  Endpoint .4  5Cyclic Redundancy CheckCRC .5  Out Token  In Token Control Transfer : Setup Token  In Token Faculty of Electrical and Electronic Eng. 233 Automatic Control & Automation Dept.
     1ms±500ns: Start of frame Token 11Frame number  Data Packet Data0 .1 Data1 .2 16bitCRC1024bit   Handshake Packet Acknowledge Not acknowledge  Stall            234 
Practical Class 10 Programming Microcontrollers  USB  USB  USB     USBHardware .1  . .2                    USB  USB UARTUSB   USB       FT232           FTDIUSB<>UART HardwareUSB  USB    D2XX driver & VCP driver     .COM   Faculty of Electrical and Electronic Eng. 235 Automatic Control & Automation Dept.
      D2XX driver & VCP driver D2XX.DLL Driver VCP Driver         3MB 300 KB/s          Com USB :(Virtual Com Port) VCP  ComUSB    :D2XX.DLL  DLL    FT232BM  ü VCP& D2XX.DLLFTDI ü USB1.1, USB2.0 ü  ü 300kb~2Mb ü 384FIFO  ü 128FIFO  ü VID, PID ü  ü USBUSB   USB              USB  236 
Practical Class 10 Programming Microcontrollers         11                     PWREN#   Faculty of Electrical and Electronic Eng. 237 Automatic Control & Automation Dept.
      3ms Sleep mode   Sleep=”1”   Wake up     USB  Serial Interface EngineSIE USBUSB § CRC § Start Of Packet, End Of Packet, Resume, Reset  § NRZI § PID § USB1.1USB Transceiver   D+              USB2.0,    FT232BM   6MHz48MHz   EEPROM PID, VID                238 
Practical Class 10 Programming Microcontrollers  RS232<>UART<>USB      RS232<>UART<>USB           Faculty of Electrical and Electronic Eng. 239 Automatic Control & Automation Dept.

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Embedded System Microcontroller Interactive Course using BASCOM-AVR - Lecture10

  • 1.    ‫ﺍﻟﺘﺠﺎﺭﺏ ﺍﻟﻌﻤﻠﻴﺔ‬     Programming Embedded Systems Microcontroller You Can Practice Microcontroller Programming Easily Now! WALID BALID, Tuesday, December 15, 2009
  • 2. Practical Class 10 Programming Microcontrollers Exp.28:Serial Communications RS485 RS485     RS485  RS485           RS485     A,B   VA>VB “1” VA<VB  “1”“0”    RS485 B A                      RS485 RS485 ST TI MAXIM LTC ST485 SN75176 MAX485 LTC485 :RS485 Faculty of Electrical and Electronic Eng. 213 Automatic Control & Automation Dept.
  • 3.       RS485 SPECIFICATIONS RS232 RS423 RS422 RS485 Mode of Operation SINGLE-ENDED SINGLE-ENDED Differential Differential Total Number of Drivers and 1DRIVER 1DRIVER 1DRIVER 32DRIVER Receivers on One Line 1RECVR 10RECVR 10RECVR 32RECVR Maximum Cable Length 50 FT 4000 FT 4000 FT 4000 FT 10Mb/s 10Mb/s Maximum Data Rate 20kb/s 100kb/s 100Kb/s 100Kb/s Maximum Driver Output Voltage ±25V ±6V -0.25V to +6V -7V to +12V Driver Output Signal Loaded ±5V to ±15V ±3.6V ±2.0V ±1.5V Level (Loaded Min.) Driver Output Signal Unloaded ±25V ±6V ±6V ±6V Level (Unloaded Max) Driver Load Impedance (Ohms) 3k to 7k >=450 100 54 Max. Driver Current in Power On N/A N/A N/A ±100uA High Z State Max. Driver Current in Power Off ±6mA @ ±2v ±100uA ±100uA ±100uA High Z State Slew Rate (Max.) 30V/µS Adjustable N/A N/A Receiver Input Voltage Range ±15V ±12V -10V to +10V -7V to +12V Receiver Input Sensitivity ±3V ±200mV ±200mV ±200mV Receiver Input Resistance (Ohms) 3k to 7k 4k min 4k min >=12k                   RS485                         214 
  • 4. Practical Class 10 Programming Microcontrollers  RS485 B  A       15Meter   Backbone with StubsDaisy Chain    RS485    Faculty of Electrical and Electronic Eng. 215 Automatic Control & Automation Dept.
  • 5.         RS485   PASSIVE DUPLEX CONTROL (AUTOMATIC ) ü ACTIVE DUPLEX CONTROL (RTS Pin ) ü RS485    RO, DI      Passive Duplex   ü  DE/RE Driver      No data to send  §              “1” Idle Master sends a request  §      Start Bit        Stop Bit              Check sum  Idle  216 
  • 6. Practical Class 10 Programming Microcontrollers Slave sends a response  §           add = 07        RS485 Driver Active Duplex ü   RTS Control            No data to send     § RTS          “1”     Master sends a request  §      Start Bit        Stop Bit Check sum  Idle Faculty of Electrical and Electronic Eng. 217 Automatic Control & Automation Dept.
  • 7.      Slave sends a response   add = 07       RS232  Advantages  Disadvantages        ü System-to-System       ×    Chip-2-Chip  1200 ü .Chip-2-Sensor   100kb/s RS485<>TTL ×   ü         ü  :RS485MODBUS          MODEBUS   Multi Master/Slave                   Master Device   MODEBUS          Slave Device  Slave DeviceMaster DeviceQueryMODEBUS Slave Function Start Start Byte Count Data CRC Address Code Address Hi Address Lo  218 
  • 8. Practical Class 10 Programming Microcontrollers Slave Function Byte Start Data CRC Address Code Count Address Stream CRC Low CRC Hi 1 byte 1 byte 1 byte 2 byte 0 ~ 252 byte 1~2 byte 1~252Slave Address • Function code • Byte Count • Start Address • 255 byte maxData Stream •  Cyclic Redundancy CheckCRC •  Inter-frame-time              t3.5     Data  t1.5      Inter-character time-out (t1.5) = 750μs Inter-frame delay (t3.5) = 1.750ms Faculty of Electrical and Electronic Eng. 219 Automatic Control & Automation Dept.
  • 9.      70Byte9600bps   Slave address   70 ×8 = 560 × 1000 = .    58ms                .t3.5= 1.75ms   Start Master Set Control Pin Waitms 10 Send Data Frame Reset Control Pin Waitms 100 End  220 
  • 10. Practical Class 10 Programming Microcontrollers   Start Slave NO UART INT Yes Byte1 is Disable UART Slave ADD Wait 90ms NO Yes Get the data at the 90ms Passed? UART Interface (MSB First, LSB Last ) Yes Enable UART NO Check Count Check CRC Programming YES OK Ignore Data Set Data Value End  MasterSlaveResponceMODEBUS     Slave                               Slave Function Byte CRC Address Code Count CRC Low CRC Hi 1 byte 1 byte 1 byte 1~2 byte Slave  CRC Faculty of Electrical and Electronic Eng. 221 Automatic Control & Automation Dept.
  • 11.       RS485| Full-DuplexHalf-DuplexRS485             RS485     222 
  • 12. Practical Class 10 Programming Microcontrollers  UART<>RS458 Max485           Config Print0 = Porte.2 , Mode = Set .RS485 “DE”“1”Config Print0  “0”“DE” “DE”   Faculty of Electrical and Electronic Eng. 223 Automatic Control & Automation Dept.
  • 13.       Microcontroller is Master, PC is Slave $regfile = "m128def.dat" $crystal = 8000000   $baud = 9600 '------------------ Config Print0 = Porte.2 , Mode = Set  Config Pine.2 = Output  DE Config Pine.4 = Input   Key1 Alias Pine.4 Porte.4 = 1 '------------------   Dim Msg As String * 100 '------------------ Do Debounce Key1 , 0 , Sendall , Sub Loop End '------------------ Sendall: Print "This is RS485 Test Program" Print "RS458 Protocol Done Based-on MAX485" Print "University of Aleppo - Syria" Print "Faculty of Alectrical & Electronic Engineering"   Print "Control Department" Print "Fourth Year Students" Print "Computer Aided Design Session" Print "Unfutunality This Was The Last Session Lab" Print "2nd Semester" Print "See You Next Semester Guys ;)" Print "Kindest Regards" Print "Walid BALID" Print ":) :) :) :) :) :) :) :) :) :) :) :)" Wait 1 Return                224 
  • 14. Practical Class 10 Programming Microcontrollers  Microcontroller is Slave, PC is Master $regfile = "m128def.dat" $crystal = 8000000   $baud = 9600 '-------------------------  DE Config Porte.2 = Output Config Print = Porte.2 , Mode = Reset   Open "comd.3:9600,8,n,1" For Output As #1  UART Open "comd.2:9600,8,n,1" For Input As #2   Config Serialin = Buffered , Size = 250   Enable Interrupts '-------------------------   Dim Msg As String * 250 '------------------------ Do   If Ischarwaiting() = 1 Then Input Msg UART Print #1 , Msg  End If Loop  UART End                                       Faculty of Electrical and Electronic Eng. 225 Automatic Control & Automation Dept.
  • 15.       RS232<>RS458 RS232<>RS458 RS232<>RS458          226 
  • 16. Practical Class 10 Programming Microcontrollers  RS232<>UART<>RS458       RS232<>UART<>RS458        Max232 UART Max485 UART    RS232<>UART<>RS458 Faculty of Electrical and Electronic Eng. 227 Automatic Control & Automation Dept.
  • 17.      Exp.29:Serial Communications USB USB     USB            USB     USB  USB  480Mb/s ü  . Plug & Play  ü   ü  127 ü   :USB  USB 1.0 & USB 1.1 & USB 2.0& USB 3.0USB  USB 1.01.5 Mbits/s Low Speed § USB 1.112 Mbits/s Full Speed § .USB 2.0480 Mbits/s High Speed §  .USB 3.04800 Mbits/s  §        USB  ”Host Controlled”  USB        )                USB  228 
  • 18. Practical Class 10 Programming Microcontrollers ”On-The-Go”    USB   ü  ü  HUB USB       Plug& Play  Plug & Play USB   USB      VID, PID   USB   Faculty of Electrical and Electronic Eng. 229 Automatic Control & Automation Dept.
  • 19.       USB   USB  A §  B §     D- & D++5v & GNDUSB  VCC1   D-2   D+3     GND4   '1'       D+&D-  USB    D-  '0' D+ '1'    :(Non Return to Zero Invert) NRZI NRZIUSB   '0' '1''0'  '1'    '1'    230 
  • 20. Practical Class 10 Programming Microcontrollers       USB  D- D+ D- .1 D+ .2  .3      USB  USB  USB                 USB Device USB  USB Function Host Controller IC USB  USB  USBUSB Function          USB Function  Endpoint   EndpointUSB Function  InOut Faculty of Electrical and Electronic Eng. 231 Automatic Control & Automation Dept.
  • 21.       USB    EP2 In  USB Function        USB1  EP1 In [Addr : 2] [Endpoint : EP1] [In]  USB1 PipePipe  EP0 In & EP0 Out  Pipe0  Pipe        Pipe   Control Transfers §  232 
  • 22. Practical Class 10 Programming Microcontrollers Interrupt Transfers § Isochronous Transfers § Bulk Transfers §  USB          Frame     USB    1ms  USB1.1, USB2.0  125µs Transaction                    Token Packet   In Token  Synchronization .1    Packet Identity PID .2    128Address .3  Endpoint .4  5Cyclic Redundancy CheckCRC .5  Out Token  In Token Control Transfer : Setup Token  In Token Faculty of Electrical and Electronic Eng. 233 Automatic Control & Automation Dept.
  • 23.      1ms±500ns: Start of frame Token 11Frame number  Data Packet Data0 .1 Data1 .2 16bitCRC1024bit   Handshake Packet Acknowledge Not acknowledge  Stall            234 
  • 24. Practical Class 10 Programming Microcontrollers  USB  USB  USB     USBHardware .1  . .2                    USB  USB UARTUSB   USB       FT232           FTDIUSB<>UART HardwareUSB  USB    D2XX driver & VCP driver     .COM   Faculty of Electrical and Electronic Eng. 235 Automatic Control & Automation Dept.
  • 25.       D2XX driver & VCP driver D2XX.DLL Driver VCP Driver         3MB 300 KB/s          Com USB :(Virtual Com Port) VCP  ComUSB    :D2XX.DLL  DLL    FT232BM  ü VCP& D2XX.DLLFTDI ü USB1.1, USB2.0 ü  ü 300kb~2Mb ü 384FIFO  ü 128FIFO  ü VID, PID ü  ü USBUSB   USB              USB  236 
  • 26. Practical Class 10 Programming Microcontrollers         11                     PWREN#   Faculty of Electrical and Electronic Eng. 237 Automatic Control & Automation Dept.
  • 27.       3ms Sleep mode   Sleep=”1”   Wake up     USB  Serial Interface EngineSIE USBUSB § CRC § Start Of Packet, End Of Packet, Resume, Reset  § NRZI § PID § USB1.1USB Transceiver   D+              USB2.0,    FT232BM   6MHz48MHz   EEPROM PID, VID                238 
  • 28. Practical Class 10 Programming Microcontrollers  RS232<>UART<>USB      RS232<>UART<>USB           Faculty of Electrical and Electronic Eng. 239 Automatic Control & Automation Dept.