Introduction to PIC 16C74X Microcontroller

8/12/2019 Introduction to PIC 16C74X Microcontroller

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Introduction to PIC 16C74X

MicrocontrollerBy,

Arulselvam K


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Introduction

PIC Peripheral Interface Controller given by

Microchip Technology.

It is designed with Harvard architecture. Harvard architecture is designed with

separate busses for handling data and

address. Hence execution time for instruction

is less as compared to Van Neumann

architecture.


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Features of PIC 16C74

8 Bit microcontroller having 40 pins.

It has 33 I/O pins for connecting peripheral devices. (5ports)

Port A(6 bits)-A/D Converter

Port B(8 bits) External Interrupts

Port C(8 bits)- Serial Port/ Timer I/O

Port D(8 bits)- Parallel Slave port

Port D(3 bits) A/D converter

Each I/O pin is capable of handling current of 25 mA . It has inbuilt three programmable timers.

Timer 0 8Bits, Timer 1-16 bits, Timer 2-8 bits

Inbuilt 8 bits A/D converter with 8 Channels


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Features of PIC 16C74

4K X 14 bits of program memory.

256 bytes of data memory ( includes generalpurpose and special purpose reg).

Inbuilt PWM generation(CCP 1 and CCP2)

12 independent Interrupt sources

It has most power full instruction set having 35

instruction. Power On Reset feature

Brown Out Rest feature


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Memory Organization

Memories available in PIC micro controller are

classified as follows.

1. Program Memory2. Data Memory


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Program Memory

PIC 16C7X series micro controller has 13 bit

program counter. Hence It can map memory

space with (0000h to 1FFFh).


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Data Memory

It has two register banks(Bank 0 and Bank1 )

and each bank having 128 bytes of memory.

Appropriate bank is selected as using RP0 bitSTATUS register.


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Some Special Register

STATUS Register

W- Register

FSR(File Selection Register INDF

Program counter(PC)

PCL(8 bits)

PC Lath(Lower 5 bits are used)

Program counter(PC) (8 Level)


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Pin Configuration of PIC 16C74A


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Addressing Modes

Direct Addressing

In-direct addressing


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Instruction set

PIC 16C74A has only 35 instruction.

Most of the instructions are byte oriented and itrequires two parameters.

First Parameter: Name of SPR or GPR Second Parameter : Destination of the result

F- Destination -> source

W -Destinaion-> Work register

Bit oriented instruction also have two parametersFirst parameter name of the data memory

Second bit address of the particular memory


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List of Instruction

1. bcf f, index

1. Ex: bcf STATUS , RP0

2. Ex: bcf STATUS , 5

2. bsf f, index

3. clrw

4. clr f

5. movlw k1. Ex : movlw 30h

2. Ex : movlw 20


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List of Instruction

6. movf f, F(W)

F(w) can be replaced by F or W

Ex: movf INDF, W Ex movf INDF, F

7. mov wf, f

- moves w to f

- ex : movwf TMR0 ( w to TMR0)


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List of Instruction

8. swapf f, F(W)

- Ex: swapf 30h , F

9. andlw k-Ex: andlw 10h

10. andwf f, F(W)

-Ex: andwf TMR1L, F


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List of Instruction

11. iorlw k

12. iorwf f, F(W)

13. xorlw k

14. xorwf f, F(W)


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List of Instruction

15. addlw k

- Ex: addlw 33h(w=w+33h)

16. addwf f, F(W)- Ex: addwf PORT A, F(PORT A=W+PORT A)

- Ex: addwf PORT A, W(W=W+PORT A)

17.sublw k- Ex: sublw 22h (W=W-22h)


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List of Instruction

18. subwf f, F(W)

19. rlf f, F(W)- Ex: rlf PORT A, W

20. rrf f, F(W)

- Ex: rrf PORT B, F


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List of Instruction

21. btfsc f, index

- Ex: btfsc STATUS , 2 (Check for ZERO flag)

22. btfss f, index- Ex: btfsc STATUS, 0 (Check for CARRY flag)

23. decf f, F(W)

24. incf f, F(W)25. comf f, F(W)


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List of Instruction

26. decfsz f, F(W)

- Ex : decf 65h, F (Check for Zero)

27. incfsz f, F(W)

-Ex: incfcz 66h, F (Check for Zero)28. goto label

29. call label

30. return

31. retlw k32. retfie (Re-enable interupts)


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List of Instruction

33. nop

34.clrwdt

35. sleep


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Sample Programs

1. Addition of two nos:

movlw 02h ;

addlw 32h;


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Sample Programs

2. Addition of array of nos.

- Array of 5 nos stored in RAM location startsfrom 20h

COUNT EQU 05;

movlw COUNT;

movwf 30h;

movlw 20h;

Introduction to PIC 16C74X Microcontroller

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