1. PIC18
CH. 4

2. PIC18F452/458 Peripherals – Data ports – PORTA 6-bit PORTB 8-bit
PORTC 8-bit
PORTD 8-bit
PORTE 3-bit
33 pins out of 40 pins are set aside for the 5 ports – PORTA, …

3. I/O, other functions – for each port
To use any of these ports as an input or output port – it must be programmed
I/O, other functions – for each port
Each port has three SFRs associated with it [see T. 4.2]. These registers r designated as 
PORTx - PORTA, PORTB
TRISx - TRIState
LATx - LATch

4. 5.1 arithmetic ADDLW k ;WREG = k + WREG
ADDWF fileReg, d ; = WREG + fileReg’s byte
F = F + W
ADDWFC  add with carry
For 16-bits addition, if any carry in the lower-byte addition [ADDWF] – then this carry will be added by ADDWFC for higher-byte
F = F + W + carry

5. Subtraction:
SUBLW k ;WREG = k – WREG
SUBWF  destination = fileReg – WREG
SUBWFB  dest = fileReg – WREG – borrow
SUBFWB  dest = WREG – fileReg - borrow

6. Multiplication: byte-by-byte multiplication only – unsigned data
MULLW k
W x k
Result = 16-bit
One of the operand must be in the WREG
Another operand must be a literal value [k]
Results in the special function registers
PRODH (higher-byte) & PRODL (lower-byte)

7. Division of unsigned numbers
No instruction for the division of byte/byte!
Perform a division by repeated subtraction
Numerator is  placed in a fileReg
Denominator is  subtracted from it repeatedly
Quotient is  no. of times we subtracted
Remainder is  in fileReg upon completion

8. Logical ANDLW k ; W = W AND k ANDWF fileReg, d
IORLW k ;inclusive-OR or logical OR
IORWF f, d
XORLW k ;w = w EX-OR k
XORWF f, d

9. 6. Addressing modes
PIC18 has 4 addressing modes – by which a CPU can access data
Immediate
Direct
Register indirect
Indexed-ROM

10. 6.7 MACRO
Group of instructions does a task – but this gr. is used repeatedly
 use MACRO
 use user-defined function
Not writing the same – again n again; to avoid errors of same code;  use MACRO
Meaning -
1. A single, user-defined command that is part of an application and executes a series of commands.
2. A shorthand representation for a number of lines of code.

11. ---------------------------------------------------------
name MACRO variable1, v2, … …
ENDM
MACRO directive indicates the starting…
ENDM directive signals the end
‘name’ – ইচ্ছামত but must be unique

12. Move from W to fileReg?  MOVWF Move from F to F?  ??
Move to WREG?  MOVLW
Move from W to fileReg?  MOVWF
Move from F to F?  ??
MOVLFx MACRO k, myReg
MOVLW k
MOVWF myReg
ENDM