ASM for dummies

[carl_schell]

Squibcakes -

Hi. I found a book that I consider to be one of the best availible sources to beginners in ASM programming. It is:

PIC In Practice by: David W. Smith

a quick search at amazon.com should lead you to this book

He does an outstanding job of taking you from knowing absolutely nothing about asm and pics to feeling like you could easily write lengthy programs in assembly. He has many projects in the book, such as LCD, A to D, EEPROM, Receivers and Transmitters and of course the blinky program. He uses 5 different pics to demonstrate with and gives very good directions, tips, ideas and encouragement.

His book is actually what got me interested in PICs to begin with. It is a 240 page book that you will read cover to cover in 1 month...you will become addicted to it. It is very worth the $26 dollars I paid for it! However, in time you will probably drift back to pbp. But I think you will get a lot out of this book and learning a bit about assembly...kinda makes pbp easier to picture what is going on inside. Anyhow, enough of my speach...Best of luck to you

Carl

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PIC Development Boards with Bootloader!

www.schellelectronics.com
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[i_am_tye]

hi i used the code form this page and adapted it, thank you,
it uses all 8 bits of portb and 2 bits of portc, the 2 bits of port c are used to multiplex 2 sets of 8 leds, so ya get 16 outputs. 3 shown here. what i want to know how could i impliment a lookup table for setting the data in port b and port c. i have shown 3 patterns in this code , but has 16, long code.
please help driving me nuts, thought it may also help others who got to this section




list P=PIC16F870 ; Tells MPASM the target processor

include "p16f870.inc"

__config _XT_OSC & _WDT_ON & _PWRTE_ON & _BODEN_ON & _LVP_OFF & _CPD_ON & _CP_OFF & _DEBUG_OFF & _WRT_ENABLE_OFF

; Tells MPASM our Configuration Fuse Definitions
;
STATUS EQU 3h ;Define lable STATUS to 3
PORTB EQU 6h ;Define lable PORTB to 6 (Bank 0)
TRISB EQU 86h ;Define lable TRISB to 6 (Bank 1)
PORTC EQU 7h ;Define lable PORTB to 6 (Bank 0)
TRISC EQU 87h ;Define lable TRISB to 6 (Bank 1)
;

COUNT_a EQU 20h ;Define lable COUNT_1 to RAM adress 20h
COUNT_b EQU 21h ;Define lable COUNT_2 to RAM adress 21h
DELAY EQU 22H

;
STARTADR: ORG 000h ;Point to adress 000h which is the start adress
GOTO START ;Jump over the fist adresses and to START
;
ORG 010h ;Point to adress 010h.
START: MOVLW b'00100000' ;Load W register so bank 1 will be set (see statusreg in datasheets)
MOVWF STATUS ;Move W into STATUS and now Bank 1 will be selected
MOVLW b'00000000' ;Load W with data direction for TRISB 1=input 0=output (binary for lights)
MOVWF TRISB ;Move W into TRISB and RB0 will be an output(all outputs hehe =00000000)
;extra bits i added for setting trisc
MOVLW b'11001111' ;Load W with data direction for TRISC 1=input 0=output (binary for lights)rc4 and rc5 as outputs
MOVWF TRISC ;Move W into TRISC and RB0 will be an output(all outputs hehe =00000000)
;
MOVLW b'00000000' ;Load W register so bank 0 will be set (see statusreg in datasheets)
MOVWF STATUS ;Move W into STATUS and now Bank 0 will be selected
;

BACK:
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;1st set led is 10000000 00000000
;port b is the pattern and port c is the bank
;
MOVLW b'00000001' ;load pattern into W
CALL ledbankleft ;load pattern into portb and select right led bank, ie port rc04

MOVLW b'00000000' ;
CALL ledbankright ; select right led bank, ie port rc05
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;
;2nd set led is 110000000 00000000

MOVLW b'00000011' ;
CALL ledbankleft

MOVLW b'00000000' ;
CALL ledbankright
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;
;3nd set led is 11100000 00000000

MOVLW b'00000111' ;
CALL ledbankleft

MOVLW b'00000000' ;
CALL ledbankright
GOTO BACK

loop:
MOVLW 07fh ;Load W with Loop time
; MOVLW DELAY
MOVWF COUNT_a ;Move W to RAM adress
;
NEXT_a: MOVLW 07fh ;Load W with Loop time
MOVWF COUNT_b ;Move W to RAM adress
NEXT_b: DECFSZ COUNT_b,F ;Decrease COUNT_2 and execute next instruction if result not zero.
GOTO NEXT_b ;
;
DECFSZ COUNT_a,F ;Decrease COUNT_1 and execute next instruction if result not zero.
GOTO NEXT_a ;
;2ndloop
MOVLW 07fh ;Load W with Loop time
MOVWF COUNT_a ;Move W to RAM adress

NEXT_c: MOVLW 07fh ;Load W with Loop time
MOVWF COUNT_b ;Move W to RAM adress
NEXT_d: DECFSZ COUNT_b,F ;Decrease COUNT_2 and execute next instruction if result not zero.
GOTO NEXT_d ;
;
DECFSZ COUNT_a,F ;Decrease COUNT_1 and execute next instruction if result not zero.
GOTO NEXT_c ;
RETURN

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;;;
ledbankright: MOVWF PORTB
MOVLW b'00100000' ;select led bank 1
MOVWF PORTC ;Move W to port B and now RC5 will go Hi.
CALL loop
RETURN
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;;;
ledbankleft: MOVWF PORTB
MOVLW b'00010000' ;select led bank 1
MOVWF PORTC ;Move W to port B and now RC5 will go Hi.
RETURN
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;;;
END

[dw_picbasic]

Check out this PIC simulator software.
Its around $40 U.S. and well worth it!!!
The simulator is really awesome.
If you know what having an oscilloscope does for you in terms of seeing whats going on inside a circuit. You'l find the same thing with this simulator.

Its one of the best tools for playing with assembly I've found.

InstPIC Simulator IDE official web site is on the following address:
http://www.oshonsoft.com/alls and is up and running in a heart-beat.