MICRO_CONTROLLER PRACTICE1_Programming.pptx
- 1. MICROCONTROLLER PRACTICE BY Mr Serge Paulin TCHASSO
- 2. Definition of a microcontroller A microcontroller (MCU) could be very summarily defined like a system of complete control, dedicated to a particular application which is equipped with logic functions and most of the other elements necessary to his operation. The microcontroller is therefore as a microcomputer built in a chip. The microcontroller is is programmable integrated circuit. It behaviour depends on a program that must be written and uploaded into it memory
- 3. Elements of the internal structure of a microcontroller The memory unit The central processing unit The Input-Output unit Buses The Timer unit The Watchdog The Analogue To Digital Converter unit The Serial Communication unit The USB unit
- 4. The Memory unit Memory is part of the microcontroller whose function is to store data. It is divided into 03 three parts: The program memory contains the program, therefore the instructions to achieve, and possibly data needed by the program (for example variables). The program memory can be a ROM. In this case the program is sent to the microcontroller once. The ROM is sometimes replaced by an EEPROM or flash memory, which can be electrically written and erased several times. The RAM (Random Access Memory): makes it possible to store data during the execution of the program. The EEPROM (Programmable Electrically Erasable Read Only Memory): this memory can be erased and reprogrammed, like the flash. It is used to store data, in case for example of power supply failure.
- 5. The Central Processing Unit CPU (Central Processing Unit) it is the "brain" of the system. It is The internal microprocessor that reads and executes the instructions of the program stored in the program memory. Its memory locations are called registers.
- 6. The Input-output unit This unit enables the microcontroller to communicate with the outside world through locations called PORTS. There are three types of ports: Input ports Output ports Bidirectional ports When working with ports, we first of all choose the port, then send data to it or receive data from it.
- 7. The Serial communications unit It is used to exchange data with the external world while using only three cables: transmit, receive and ground. There are two types of serial communications: asynchronous (serial communication interfaces, SCI or UART) and synchronous (serial peripheral interface, SPI). These interfaces are used, for example, to connect the MCU to a PC (SCI) or an EEPROM or another microcontroller, a GSM MODEM, a Bluetooth module...
- 8. The Timer unit It is used as an internal base time for the system; it also generates signals and counts events or interruptions. Some microcontrollers have a watchdog timer (watchdog): if this device is not re-initialized by the program after preset intervals, it will consider that there is a problem in the software and causes a hardware reset. The A/D converter unit This module first of all converts the analogue signal into a digital signal before it is processed by the CPU Unit Generally the Analogue to Digital Converter unit has a resolution of 10 bits and the range of analogue value to be converted is 0V to 5V
- 9. The block diagram of a microcontroller The diagram below summarizes the working procedure of a microcontroller.
- 10. The internal architecture and Instruction Set All upgraded microcontrollers use one of two basic design models. It is about two different ways of data exchange between CPU and memory unit. Von-Neumann architecture Harvard Architecture The Instruction Set All instructions that can be understood by the microcontroller are known as instruction set. RISC (Reduced Instruction Set Computer) In this case, the idea is that the microcontroller recognizes and executes only basic operations addition, subtraction, etc.). CISC (Complex Instruction Set Computer)
- 11. Instruction Set
- 12. Families of microcontrollers Motorola Microcontrollers Atmel Microcontrollers Atemega Microcontollers PIC Microcontrollers …
- 13. Necessary material for the implementation of a microcontroller system The microcontroller itself A compiler (MPLAB, MikroC, Proton…) A simulator (ISIS-PROTEUS) The power supply (generally DC 5V) The Oscillator The reset button (not compulsory) A microcontroller programmer Other electronics components
- 14. The microcontroller itself Physical aspect of the microcontroller OSC1/CLKIN 16 RB0/INT 6 RB1 7 RB2 8 RB3 9 RB4 10 RB5 11 RB6 12 RB7 13 RA0 17 RA1 18 RA2 1 RA3 2 RA4/T0CKI 3 OSC2/CLKOUT 15 MCLR 4 U2 PIC16F84A RA0/AN0 2 RA1/AN1 3 RA2/AN2/VREF- 4 RA4/T0CKI 6 RA5/AN4/SS 7 RE0/AN5/RD 8 RE1/AN6/WR 9 RE2/AN7/CS 10 OSC1/CLKIN 13 OSC2/CLKOUT 14 RC1/T1OSI/CCP2 16 RC2/CCP1 17 RC3/SCK/SCL 18 RD0/PSP0 19 RD1/PSP1 20 RB7/PGD 40 RB6/PGC 39 RB5 38 RB4 37 RB3/PGM 36 RB2 35 RB1 34 RB0/INT 33 RD7/PSP7 30 RD6/PSP6 29 RD5/PSP5 28 RD4/PSP4 27 RD3/PSP3 22 RD2/PSP2 21 RC7/RX/DT 26 RC6/TX/CK 25 RC5/SDO 24 RC4/SDI/SDA 23 RA3/AN3/VREF+ 5 RC0/T1OSO/T1CKI 15 MCLR/Vpp/THV 1 U3 PIC16F877 The microcontroller in the Proteus simulator
- 15. A compiler (MPLAB, MikroC, Proton…) MikroC environment MPLAB environment
- 16. A simulator (ISIS-PROTEUS) Many softwares can be used as simulator: ISIS-Proteus, Orcad, PSpice, Fritzing … But we will use ISIS-Proteus as working tool ISIS-Proteus environment
- 17. The power supply (generally DC 5V) Pin 1: Vcc, representing +5V, and connected to the red wire. Pin 2: Data-, connected to the white wire. Pin 3: Data+, connected to the green wire. Pin 4: representing the Ground, connected to the black wire.
- 18. The Oscillator circuit The frequency of the oscillator is the one written on the crystal oscillator The frequency of the oscillator is 5V OSC1/OSC2
- 19. The reset button (not compulsory) The RESET pin is labeled
- 23. Microcontroller applications Microcontrollers are integrated in all domains of our life such as: Super market, in cash registers; Alarm clock; Digital camera; Mouse; Mobile phone; Automobile industry (safety systems, fuel injection, …); Traffic signals; Refrigerator; Etc.