;**************************************************************
; REMOCLON.ASM 15 December 2001
;**************************************************************
;
; This PIC16LF84 program emulates the Zilog chip inside the
; remote intended for use with the Archos Jukebox 6000
;
; Written by Tjerk "T.J." Schuringa, hardware engineer (ouch)
;
;**************************************************************

	LIST 		P=16F84, F=INHX8M
	__CONFIG _CP_OFF & _WDT_OFF & _XT_OSC
	
	#include ".\p16f84.inc"

;**************************************************************
;  f_osc = 429 kHz yields cycle time of 9.32 µs
;**************************************************************

; Equates

RESET_V		EQU	0x0000		; Address of RESET Vector
OSC_FREQ	EQU	D'429000'	; Oscillator Frequency is 429 kHz
VOLDN		EQU	0x77
CMDVOLDN		EQU	0xc0
VOLUP		EQU	0x7a
CMDVOLUP		EQU	0xa0
PREV		EQU	0xef
CMDPREV		EQU	0x88
NEXT		EQU	0xcf
CMDNEXT		EQU	0x90
STOP		EQU	0x7f
CMDSTOP		EQU	0x84
PLAY		EQU	0xaf
CMDPLAY		EQU	0x82

; Registers
KEYPAD 		EQU	0x0F
DATABYTE	EQU	0x10
BITCOUNT	EQU	0x11
WAIT		EQU	0x12

;**************************************************************
; Begin Program
;**************************************************************

	ORG	RESET_V			; RESET vector location
RESET		GOTO	START
	ORG	4			; INT vector
		GOTO	WAKE

;**************************************************************
; Initialization Routine
;**************************************************************

START					; POWER_ON Reset (Beginning of program)
		CLRF	STATUS		; Do initialization, Select bank 0
		CLRF	INTCON		; Clear int-flags, Disable interrupts
		BSF	INTCON,GIE	; Enable Global INT, needed for wake on PORTB
		CLRF	PCLATH		; Keep in lower 2KByte

		CLRF	PORTA		; ALL PORT output should output Low.
		CLRF	PORTB

		BSF	STATUS, RP0	; Select bank 1
		MOVLW	0xff
		CLRF	TRISA		; RA4-0 Outputs
		MOVWF	TRISB		; RB7-0 Inputs
		BCF	OPTION_REG, NOT_RBPU
					; Enable PORTB pull-ups

		BCF	STATUS, RP0	; Select bank 0
		SLEEP			; Go to sleep

;**************************************************************
; Wake from Keypress
;**************************************************************

WAKE
		MOVF	PORTB,0		; Read PortB
		MOVWF	KEYPAD		; Store keypad value
		MOVLW	VOLDN
		XORWF	KEYPAD
		BTFSC	STATUS,Z	; Test if zero
		GOTO	OUTVOLDN
		MOVLW	VOLUP
		XORWF	KEYPAD
		BTFSC	STATUS,Z	; Test if zero
		GOTO	OUTVOLUP
		MOVLW	PREV
		XORWF	KEYPAD
		BTFSC	STATUS,Z	; Test if zero
		GOTO	OUTPREV
		MOVLW	NEXT
		XORWF	KEYPAD
		BTFSC	STATUS,Z	; Test if zero
		GOTO	OUTNEXT
		MOVLW	PLAY
		XORWF	KEYPAD
		BTFSC	STATUS,Z	; Test if zero
		GOTO	OUTSTOP
		MOVLW	STOP
		XORWF	KEYPAD
		BTFSC	STATUS,Z	; Test if zero
		GOTO	OUTPLAY
		CALL	WAIT10MS	; Debounce
		CALL	WAIT10MS
		CALL	WAIT10MS
		CALL	WAIT10MS
		CALL	WAIT10MS
		CALL	WAIT10MS
		CALL	WAIT10MS
		CALL	WAIT10MS
		CALL	WAIT10MS
		CALL	WAIT10MS
		SLEEP			; There was no match

;**************************************************************
; Surely there must be a more intelligent way to solve this...
;**************************************************************

OUTVOLDN
		MOVLW	CMDVOLDN
		CALL	PUTCHAR
		SLEEP
OUTVOLUP
		MOVLW	CMDVOLUP
		CALL	PUTCHAR
		SLEEP
OUTPREV
		MOVLW	CMDPREV
		CALL	PUTCHAR
		SLEEP
OUTNEXT
		MOVLW	CMDNEXT
		CALL	PUTCHAR
		SLEEP
OUTSTOP
		MOVLW	CMDSTOP
		CALL	PUTCHAR
		SLEEP
OUTPLAY
		MOVLW	CMDPLAY
		CALL	PUTCHAR
		SLEEP

;**************************************************************
; Subroutine PUTCHAR
; Output the RS232 Character
;**************************************************************

PUTCHAR
		MOVF	DATABYTE
		MOVLW	0x07
		MOVWF	BITCOUNT
MORE
		RRF	DATABYTE,1	; Rotate DATABYTE through Carry
		BTFSS	STATUS,C	; Test Carry
		GOTO	ZERO
ONE
		BSF	PORTA,4	; Send a one
		GOTO	NEXTBIT
ZERO
		BCF	PORTA,4	; Send a zero
NEXTBIT
		NOP
		NOP
		NOP
		NOP
		NOP
		DECFSZ BITCOUNT
		GOTO	MORE

; CHECK CORRECT DELAY!!! Need 11 cycles total per bit for 9600 baud (approx...)

		CALL	WAIT10MS
		CALL	WAIT10MS
		CALL	WAIT10MS
		CALL	WAIT10MS
		CALL	WAIT10MS
		CALL	WAIT10MS
		CALL	WAIT10MS
		CALL	WAIT10MS
		CALL	WAIT10MS
		CALL	WAIT10MS
		RETURN

;**************************************************************
; Subroutine WAIT10MS
; Wait 10 ms
;**************************************************************

WAIT10MS				; Do nothing for some time (10 ms)
		MOVLW	0xd7
		MOVWF	WAIT
LOOP		
		NOP
		NOP
		DECFSZ	WAIT,1
		GOTO	LOOP
		RETURN	


	END