Anyway, this should be enough to get you started with using PICs to control MO units. I used a LK202-25.
Code: Select all
title "Keypad Echo"
LIST R=DEC ; Sets number base to decimal
INCLUDE "p16f628.inc" ; Includes microchip configuration for this processor
__CONFIG _CP_OFF & _WDT_OFF & _HS_OSC & _PWRTE_ON & _LVP_OFF & _MCLRE_ON
; CP - Copy protection (off)
; WDT - Watchdog timer (off)
; HS_OSC - I'm using a high speed oscillator (20Mhz)
; PWRTE - Power up timer delay (on), leaves a delay for voltages to stabilise
; LVP - Low voltage programming (off)
; MCLRE - Holds MCLR pin high if on (on)
CBLOCK 0x20 ; Declare variable addresses starting at 0x20
DELAY,DELAYTMP
ENDC
;##### Macros #####
DELAY_MILLI macro TIME
movlw TIME
movwf DELAY
call DELAY_MS
endm
DELAY_MICRO macro TIME
movlw TIME
movwf DELAY
call DELAY_US
endm
SENDDATA macro DATA
movlw DATA
call TRANSMIT
endm
CLEARSCREEN macro
movlw 0xFE
call TRANSMIT
movlw 0x58
call TRANSMIT
endm
;##### Program Code #####
ORG 0
goto MAIN
;##### Subroutines #####
DELAY_US ; busy wait of DELAY us
nop ; (1)
nop ; (2)
decfsz DELAY,f ; test DELAY count (3)
goto DELAY_US ; loop if not done (4,5)
return ; gtfo (4,5)
DELAY_MS ; busy wait of DELAY ms
movf DELAY,w
movwf DELAYTMP ; save DELAY time
DELAY_MS_LOOP ; inner loop
movlw 245 ; load 245 (1)
movwf DELAY ; into DELAY (2)
call DELAY_US ; wait 245us (3-249)
movlw 245 ; load 245 (250)
movwf DELAY ; into DELAY (251)
call DELAY_US ; wait 245us (252-498)
movlw 245 ; load 245 (499)
movwf DELAY ; into DELAY (500)
call DELAY_US ; wait 245us (501-747)
movlw 246 ; load 246 (748)
movwf DELAY ; into DELAY (749)
call DELAY_US ; wait 246us (750-997)
decfsz DELAYTMP,f ; test DELAYTMP count (998)
goto DELAY_MS_LOOP ; loop if not done (999,1000)
return ; gtfo (999,1000)
INIT
bsf STATUS,RP0 ; RAM PAGE 1
movlw b'00000010' ; RB7-RB4 and RB1(RX)=input, others output
movwf TRISB
movlw 0x40 ; 0x40 = 19.2kbps
movwf SPBRG
movlw b'00100100' ; brgh = high (2)
movwf TXSTA ; enable Async Transmission, set brgh
bcf STATUS,RP0 ; RAM PAGE 0
movlw b'10010000' ; enable Async Reception
movwf RCSTA
DELAY_MILLI 250
DELAY_MILLI 250
DELAY_MILLI 250
DELAY_MILLI 250
DELAY_MILLI 250
DELAY_MILLI 250
DELAY_MILLI 250
DELAY_MILLI 250
return
TRANSMIT
movwf TXREG ; send data in W
bsf STATUS,RP0 ; RAM PAGE 1
TRANSMITTEST
btfss TXSTA,TRMT ; (1) transmission is complete if hi
goto TRANSMITTEST
bcf STATUS,RP0 ; RAM PAGE 0
return
;##### Main Program #####
MAIN
call INIT
CLEARSCREEN
receive
btfss PIR1,RCIF ; check for received data
goto receive
movf RCREG,W ; save received data in W
call TRANSMIT ; send received data to display
goto receive
END
