MC_module_3_2022.pdf

Microcontroller- 16EC2304
VI - Semester

MC-Syllabus
Module-1
▪ Introduction to Microcontroller - Microprocessor and Microcontroller Characterization, Components of a
Microcontroller, Microcontroller Architecture.
• Main Characteristics of PIC Microcontrollers - Arithmetic and Logic Unit (ALU), Working Register in PIC
Microcontrollers, Machine Cycles and Execution of Instructions, Pipelining for Instruction Execution, Oscillators,
Configuration Bits, Reset Options, Low-Power Consumption Mode, Watchdog Timer, Program Counter,RISC,
Compare Harvard architecture with von Neumann architecture.
Module-2
▪ Memory in Microcontrollers – Memory Organization, RAM, Data Memory, EEPROM, Flash Memory.
• Instruction Set and Assembler Language Programming - Arithmetic Instructions, Logic and Compare
instructions, Rotate Instruction and Data Serialization, Branch Instructions and Looping, Call Instructions and Stack
•

MC-Syllabus
Module-3
▪ Programming in C - Data Types and Time Delays, bit-addressable I/O, Logic Operations, Data Serialization, ROM &
RAM Allocation
Module-4
• Timers and Interrupts - Instruction Pipeline, Timers, The CCP Module, Interrupt, Examples of Timer and Interrupt
Applications.
• Parallel and Serial Communication – Parallel IO, Serial IO, advantages of serial communication over parallel,
Streaming Parallel Port, USART, SPI, I2C
Module-5
▪ Sensors and Actuators - Interfacing LED, LCD, Keypad, ADC, DAC, Buzzer, Sensor, Relays, Stepper & DC Motor

TEXT BOOKS:
[1]Fernando E. Valdes-Perez, Ramon Pallas-Areny, “Microcontrollers -
Fundamentals and Applications with PIC”, CRC Press, 1st Edition, 2009.
[2] Mazidi M. A., McKinlay R. D., Causey D., “PIC Microcontroller And
Embedded Systems.”, Pearson Education International, 2008
[3] https://ww1.microchip.com/downloads/en/devicedoc/39632c.pdf
•

REFERENCE BOOKS:
• 1. Myke Predko, “Programming and Customizing the PIC Microcontroller”, Mc Graw Hill Education, 3rd
Edition, 2008.
• 2. John B. Peatman, “Design with PIC Microcontrollers”, Prentice Hall, 1997.
• 3. Verle Milan, “PIC Microcontrollers – Programming in C”, Mikroelektronika, 1 st Edition, 2009
• For the Blended Learning
1. https://www.classcentral.com/course/swayam-microprocessors-and-microcontrollers-9894
2. https://ww1.microchip.com/downloads/en/devicedoc/39632c.pdf
3. https://circuitdigest.com/microcontroller-projects/writing-your-first-pic-microcontroller-program

Module-3-PROGRAMMING IN C
Data Types and Time Delays [2,3]
[1] Fernando E. Valdes-Perez, Ramon Pallas-Areny, “Microcontrollers - Fundamentals and Applications with PIC”, CRC Press, 1st Edition, 2009
[2] Mazidi M. A., McKinlay R. D., Causey D., “PIC Microcontroller And Embedded Systems.”, Pearson Education International, 2008
Why program a PIC18 in C programming language?
▪ Writing Programs in C are easier than in Assembly language programming(ALP).
▪ Easier to modify and update the program than Assembly language.
▪ C code is portable to other microcontrollers with no or little modifications compared to ALP.
▪ Codes available in function libraries can be used.
▪ But the hex file generated for C program is larger than the hex file generated for assembly language programming.
[2]

PROGRAMMING IN C
Data types [2]
1. Unsigned character:
▪ It is an 8 bit data type and can take values from 0-255(00-FFH)
▪ C compilers use signed char as default hence unsigned should be mentioned.
▪ Since int data types generate a large size hex files unsigned data types should be used instead.
▪ Eg. Used for counter values less than 256.
[2]

PROGRAMMING IN C
Data types [2]
2. signed character:
▪ It is an 8 bit data type uses D7bit used for the sign (-or+).
▪ 7 bits for magnitude giving values from -128 to+127.
▪ eg. Used for representing temperature (as temp can be + or -)
[2]

PROGRAMMING IN C
Data types [2]
3. unsigned int:
▪ It is an 16 bit data type and takes a value in the range 0 to 65,535 (0000H-FFFFH).
▪ eg. 16 bit unsigned int used to represent variables like memory address or counter values more than 256.
▪ Since unsigned int is 16 bit and most registers and RAM location in PIC18 are 8 bit long, use of unsigned int generates a
large hex file.
[2]

PROGRAMMING IN C
Data types [2]
3. Signed int:
▪ It is an 16 bit data type and uses D15 (of D0-D15) bit to represent the sign .
▪ Has only 15 bits for magnitude. So can represent in the range -32,768- +32,767.
▪ eg.

PROGRAMMING IN C
Time Delays [2,3]
Two ways to generate time delays
1. A simple for loop: In c programing in creating a time delay using FOR loop, the accuracy of the delay program
is affected by Compiler being used and Crystal oscillator connected to OSC1 - OSC2
2. Using timers of PIC18F4550
[2]
[2]

PROGRAMMING IN C
Byte addressable I/O [2,3]
➢ PIC18F 4550 has PORTA, PORTB, PORTC, PORTD, PORTE
➢ Each PORTx is associated with 3 registers.
➢ PORT, TRIS, LAT eg. PortB has PORTB, TRISB, LATB
➢ TRIS (data direction register)is an SFR used to make a PORT input or output port. At reset all the TRIS registers are FF i.e
input port.
➢ PortA has 7 pins, PorTB,C,D has 8 pins and PORTE has 4pins
➢ PORT register reads levels on the device pins and when writes it writes to the output latch.
➢ LAT or data latch register used to read-modify-write on the values driven by the I/O Pins.
[2] [2]

PROGRAMMING IN C
➢ TRIS (data direction register)is an SFR used to make a PORT input or output port. At reset all the TRIS registers are
FF i.e input port.
[2] [2]

PROGRAMMING IN C
➢ TRIS (data direction register)is an SFR used to make a PORT input or output port. At reset all the TRIS registers are
FF i.e input port.
[2]

PROGRAMMING IN C
Bit addressable I/O [2,3]
[3]
[3]

PROGRAMMING IN C
Portxbits.Rxy
➢ Each bit (port pins) of the PORT can be accessed
independently
➢ Portxbits.Rxy
[2]
[2]

PROGRAMMING IN C
[2]

PROGRAMMING IN C
Logic operators [2,3]
➢ Ability to perform bitwise operation
Bit-wise shift operation
[2]
[2]

PROGRAMMING IN C
Logic operators [2,3]
➢ Ability to perform bitwise operation
[2] [2]

PROGRAMMING IN C
Data Conversion in C programming [2,3]
ASCII to Unpacked BCD
Packed BCD to ASCII
ASCII to packed BCD
[2]
[2]

PROGRAMMING IN C
Checksum data in ROM:
➢ To check the integrity of the ROM data checksum calculation is
done
➢ Checksum checks for corruption in ROM data.
➢ Corruption can happen due to current surge on turning on and off.
➢ Checksum bytes is tagged to the end of the series of data.
Steps to calculate checksum data
➢ Add the bytes together drop the carries
➢ Take 2’s complement of result which is the checksum
byte.
➢ Add the series of data with the checksum byte. If the
addition is ‘0’ after dropping the carry the data is not
corrupted otherwise it is corrupted.
Example how checksum byte works is as follows
[2]
[2]

PROGRAMMING IN C
Checksum data in ROM:
Program how checksum byte works is as follows
[2]
[2]

PROGRAMMING IN C
Binary (hex) to Decimal and ASIIC conversion in C
[2]

PROGRAMMING IN C
Data Serialisation in C programming [2,3]
Data serialization is way of sending byte of data one bit at a time from a single pin.
TWO WAYs are
➢ Use of serial port. – Little control on the sequence of data being transferred.
➢ Data transfer one bit at a time and will have control on the sequence of data
and space between them. Can be done using I2C and CAN but few devices do
not support these standards. Hence data serialization using C is used.
[2]

PROGRAMMING IN C
Data Serialisation in C programming [2,3]
Data serialization is way of sending byte of data one bit at a time from a single pin.
[2]

PROGRAMMING IN C
ROM & RAM Allocation [2,3]
ROM allocation
➢ PIC 18 has maximum RAM capacity of 4K i.e from 000-FFFH
➢ PIC 18 has maximum ROM capacity of 2M i.e from 000000-1FFFFFH
➢ PIC18F4550 has maximum RAM capacity of 2K
➢ PIC18F4550 has maximum ROM capacity of 32K
➢ In assembly TBLRD instruction to access the program ROM for the purpose
of data
➢ C18 compiler also uses ROM space for storing data
[2]
[2]

PROGRAMMING IN C
ROM allocation:
➢ Allocating Program space to fixed data
➢ The keyword used is rom
[2]
[2]

PROGRAMMING IN C
ROM allocation: Near and Far storage qualifier
➢ Indicates what region the data and code should be placed
➢ Near qualifier will allocate data in the first 64KB of ROM location
➢ Far qualifier will allocate data variable within the entire 2MB of ROM
Example of near storage qualifier
[2]

PROGRAMMING IN C
ROM allocation: Near and Far storage qualifier
➢ Indicates what region the data and code should be placed
➢ Near qualifier will allocate data in the first 64KB of ROM location (for general PIC18)
➢ Far qualifier will allocate data variable within the entire 2MB of ROM(for general PIC18)
Example of Far storage qualifier [2]
[2]

PROGRAMMING IN C
ROM allocation: Using pragma directive to allocate fixed location
➢ Like ORG directive in assembly C18 compilers use pragma directive to allocate fixed location
[A] Putting code in specific ROM location
[2]
[2]

PROGRAMMING IN C
ROM allocation: Using pragma directive to allocate fixed location to data and code
➢ Like ORG directive in assembly C18 compilers use pragma directive to allocate fixed location
[B] Putting data in specific ROM location
[2]

PROGRAMMING IN C
Data RAM allocation in C18: PIC18 has 2K of RAM
[2] [2]

PROGRAMMING IN C
Near Far Storage qualifier
Example of near qualifier
Example of far qualifier
[2]
[2]

PROGRAMMING IN C
Putting data in a specific RAM Address using pragma directive
➢ Two options for pragma directive are
1. idata – initialised data
2. udata – uninitialized data
[2]
[2]

PROGRAMMING IN C
➢ Overlay storage data: Two different variables can be allocated same address location
provided the two variable's are not being used at the same time.
Example of allocation of same location to two
independent variables.
Example of allocation of different location to
two dependent variables.
[2]
[2]

References and disclaimer
The contents (pictures, text and programs) of the above slides have
been adapted from the following references (mainly reference 2). It is
only meant as a students’ reference for the course 16EC2403 –
microcontroller and not intended to be published.
[1] Fernando E. Valdes-Perez, Ramon Pallas-Areny, “Microcontrollers - Fundamentals and
Applications with PIC”, CRC Press, 1st Edition, 2009
[2] Mazidi M. A., McKinlay R. D., Causey D., “PIC Microcontroller And Embedded Systems.”,
using assembly and C for PIC18, Pearson Education International, 2008
[4] https://www.youtube.com/watch?v=Xl2nWDcy0To
[5] https://www.youtube.com/watch?v=DmwOSdwzZ3E
[6] D.V Hall, Microprocessors and Interfacing”,TATA MCGRAW HILL, revised 2nd edition

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