?? pla1b.asm
字號:
;**********************************************************************
; pla1b.asm :
; This procedure implements a simple AND-OR PLA with:
;
; 8 inputs := A7 A6 A5 A4 A3 A2 A1 A0
; 24 product terms := P23 P22 ..... P0
; 8 outputs := Y7 Y6 Y5 Y4 Y3 Y2 Y1 Y0
;
; The eight inputs are assumed to be connected to PORT RB such that
; RB0 = A0, RB1 = A1, ... , RB7 = A7.
; The outputs are programmed to appear on port RC such that
; RC0 = Y0, RC1 = Y1, ... , RC7 = Y7.
;
; This implementation optimizes program memory usage over
; speed
;**********************************************************************
;
; define RAM locations used:
;
input equ d"12" ; RAM location 12 holds input
Y_reg equ d"13" ; holds output result
Preg_a equ d"14" ; Product terms P0 to P7. Preg_a<0> = P0
Preg_b equ d"15" ; Product terms P8 to P15. Preg_b<0> = P8
Preg_c equ d"16" ; Product terms P16 to P23. Preg_c<0> = P16
Pn_x equ d"18" ;
Pn_a equ d"19" ;
OR_a equ d"20" ;
OR_b equ d"21" ;
OR_c equ d"22" ;
; define some constants and file addresses:
;
bit0 equ 0 ;
bit1 equ 1 ;
bit2 equ 2 ;
bit3 equ 3 ;
bit4 equ 4 ;
bit5 equ 5 ;
bit6 equ 6 ;
bit7 equ 7 ;
;
status equ 3 ;
port_b equ 6 ;
port_c equ 7 ;
;
; define the AND plane programming variables:
;
P0_x equ b"00000000" ;
P0_a equ b"00001111" ;
P1_x equ b"00000001" ;
P1_a equ b"00001111" ;
P2_x equ b"00000010" ;
P2_a equ b"00001111" ;
P3_x equ b"00000011" ;
P3_a equ b"00001111" ;
P4_x equ b"00000100" ;
P4_a equ b"00001111" ;
P5_x equ b"00000101" ;
P5_a equ b"00001111" ;
P6_x equ b"00000110" ;
P6_a equ b"00001111" ;
P7_x equ b"00000111" ;
P7_a equ b"00001111" ;
P8_x equ b"00001000" ;
P8_a equ b"00001111" ;
P9_x equ b"00001001" ;
P9_a equ b"00001111" ;
P10_x equ b"00001010" ;
P10_a equ b"00001111" ;
P11_x equ b"00001011" ;
P11_a equ b"00001111" ;
P12_x equ b"00001100" ;
P12_a equ b"00001111" ;
P13_x equ b"00001101" ;
P13_a equ b"00001111" ;
P14_x equ b"00001110" ;
P14_a equ b"00001111" ;
P15_x equ b"00001111" ;
P15_a equ b"00001111" ;
P16_x equ b"00000000" ;
P16_a equ b"00000000" ;
P17_x equ b"00000000" ;
P17_a equ b"00000000" ;
P18_x equ b"00000000" ;
P18_a equ b"00000000" ;
P19_x equ b"00000000" ;
P19_a equ b"00000000" ;
P20_x equ b"00000000" ;
P20_a equ b"00000000" ;
P21_x equ b"00000000" ;
P21_a equ b"00000000" ;
P22_x equ b"00000000" ;
P22_a equ b"00000000" ;
P23_x equ b"00000000" ;
P23_a equ b"00000000" ;
; define OR plane programming variables:
OR_a0 equ b"11101101" ; for output Y0
OR_b0 equ b"11010111" ;
OR_c0 equ b"00000000" ;
OR_a1 equ b"10011111" ; for output Y1
OR_b1 equ b"00100111" ;
OR_c1 equ b"00000000" ;
OR_a2 equ b"11111011" ; for output Y2
OR_b2 equ b"00101111" ;
OR_c2 equ b"00000000" ;
OR_a3 equ b"01101101" ; for output Y3
OR_b3 equ b"01111001" ;
OR_c3 equ b"00000000" ;
OR_a4 equ b"01000101" ; for output Y4
OR_b4 equ b"11111101" ;
OR_c4 equ b"00000000" ;
OR_a5 equ b"01110001" ; for output Y5
OR_b5 equ b"11011111" ;
OR_c5 equ b"00000000" ;
OR_a6 equ b"01111100" ; for output Y6
OR_b6 equ b"11101111" ;
OR_c6 equ b"00000000" ;
OR_a7 equ b"00000000" ; for output Y7
OR_b7 equ b"00000000" ;
OR_c7 equ b"00000000" ;
org 01ffh ;
begin goto main ;
org 000h ;
; define macro to evaluate 1 product (AND) term:
;
main call pla88 ;
goto main ;
;
EVAL_P MACRO Preg_x,bit_n,Pn_x,Pn_a
movf input,W ;
xorlw Pn_x ;
andlw Pn_a ;
btfsc status,bit2 ; skip if zero bit not set
bsf Preg_x,bit_n ; product term = 1
ENDM
; define macro to load OR term constants:
;
EVAL_Y MACRO OR_an,OR_bn,OR_cn,bit_n
movlw OR_an ; load constants
movwf OR_a ;
movlw OR_bn ;
movwf OR_b ;
movlw OR_cn ;
movwf OR_c ;
call EVAL1 ;
btfss status,bit2 ;
bsf Y_reg,bit_n ;
ENDM
; define procedure to evaluate 1 output (OR) term:
;
EVAL1 movf Preg_a,W ;
andwf OR_a,1 ;
movf Preg_b,W ;
andwf OR_b,1 ;
movf Preg_c,W ;
andwf OR_c,W ;
iorwf OR_a,W ;
iorwf OR_b,W ;
retlw 0 ; W = 1 implies Yn = 1
; now the PLA evaluation procedure:
;
pla88 movlw 0ffh ;
tris 6 ; port_b = input
movf port_b,W ; read input
movwf input ; store input in a register
clrf Preg_a ; clear Product register a
clrf Preg_b ; clear Product register b
clrf Preg_c ; clear Product register c
clrf Y_reg ; clear output register
and_pl EVAL_P Preg_a,bit0,P0_x,P0_a
EVAL_P Preg_a,bit1,P1_x,P1_a
EVAL_P Preg_a,bit2,P2_x,P2_a
EVAL_P Preg_a,bit3,P3_x,P3_a
EVAL_P Preg_a,bit4,P4_x,P4_a
EVAL_P Preg_a,bit5,P5_x,P5_a
EVAL_P Preg_a,bit6,P6_x,P6_a
EVAL_P Preg_a,bit7,P7_x,P7_a
EVAL_P Preg_b,bit0,P8_x,P8_a
EVAL_P Preg_b,bit1,P9_x,P9_a
EVAL_P Preg_b,bit2,P10_x,P10_a
EVAL_P Preg_b,bit3,P11_x,P11_a
EVAL_P Preg_b,bit4,P12_x,P12_a
EVAL_P Preg_b,bit5,P13_x,P13_a
EVAL_P Preg_b,bit6,P14_x,P14_a
EVAL_P Preg_b,bit7,P15_x,P15_a
EVAL_P Preg_c,bit0,P16_x,P16_a
EVAL_P Preg_c,bit1,P17_x,P17_a
EVAL_P Preg_c,bit2,P18_x,P18_a
EVAL_P Preg_c,bit3,P19_x,P19_a
EVAL_P Preg_c,bit4,P20_x,P20_a
EVAL_P Preg_c,bit5,P21_x,P21_a
EVAL_P Preg_c,bit6,P22_x,P22_a
EVAL_P Preg_c,bit7,P23_x,P23_a
or_pl EVAL_Y OR_a0,OR_b0,OR_c0,bit0
EVAL_Y OR_a1,OR_b1,OR_c1,bit1
EVAL_Y OR_a2,OR_b2,OR_c2,bit2
EVAL_Y OR_a3,OR_b3,OR_c3,bit3
EVAL_Y OR_a4,OR_b4,OR_c4,bit4
EVAL_Y OR_a5,OR_b5,OR_c5,bit5
EVAL_Y OR_a6,OR_b6,OR_c6,bit6
EVAL_Y OR_a7,OR_b7,OR_c7,bit7
; Y_reg now contains 8 output values:
wr_out clrw ;
tris 7 ; port_c = output
movf Y_reg,W ;
movwf port_c ; Y_reg -> port_c
retlw 0 ;
ZZZ nop
END
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