;; Panasonic CD Changer Emulator ;; ;; Copyright (c) 2003, Kristoffer Sj?berg ;; Inspired by Edward Schlunder ; Note: 20MHz / 4 = 5MHz. 1/5MHz = 0.2us. ; So each PIC instruction takes 0.2 microseconds long. LIST P=16F84A, R=DEC __CONFIG _WDT_OFF & _PWRTE_ON & _CP_OFF & _HS_OSC #include EXTERN send_RS232, receive_RS232, rxbyte EXTERN msecDelay, tenth_msecDelay ;-------------------------------------------------------------------------- ; Connections ;-------------------------------------------------------------------------- ; PIC16F84A Pin 1 RA2 -> DIN8C Pin 2 SCLK to Head Unit ; PIC16F84A Pin 2 RA3 -> DIN8C Pin 1 STX to Head Unit ; PIC16F84A Pin 18 RA1 -> DIN8C Pin 4 SYNC to Head Unit ; PIC16F84A Pin ?? RB0 <- DIN8C Pin ? RM to Head Unit ; RS232-Connections ; 57600bps, 8n1 ; ; Table describes a 9 pin DSUB connector (female, same applies to male) ; ; Short DB9F Pin 4 <> DB9F Pin 6 (DSR follows DTR) ; PIC TX out RB1 -> DB9F Pin 2, RXD ; PIC RX in RB2 <- DB9F Pin 3, TXD ; PIC RTS in RB3 <- DB9F Pin 7, RTS ; PIC CTS out RB4 -> DB9F Pin 8, CTS ; ; ; ; ; Make sure PIC and Head Unit have common GND. ;-------------------------------------------------------------------------- SCLK EQU 2 ; PORTA STX EQU 3 ; PORTA SYNC EQU 1 ; PORTA #DEFINE CDC_RM PORTB,0 #DEFINE DCE_RX PORTB,2 ; PICs RX-pin #DEFINE DTE_CTS PORTB,4 ;-------------------------------------------------------------------------- ; Variables ;-------------------------------------------------------------------------- ; RAM MEMORY MAP UDATA ;Temporary register for transmit to head unit txreg RES 1 ; Display information cdc_disc RES 1 cdc_track RES 1 cdc_minute RES 1 cdc_second RES 1 cdc_mode RES 1 ;RM data RM_temp RES 1 RM_byte0 RES 1 RM_byte1 RES 1 RM_byte2 RES 1 RM_byte3 RES 1 RM_bitnum RES 1 RM_pulse_length RES 1 RM_count RES 1 RM_tempbyte RES 1 receive_state RES 1 IdleLoop1 RES 1 IdleLoop2 RES 1 ; Interrupt RAM, used for saving registers during an interrupt W_TEMP RES 1 ; temporarily holds value of W STATUS_TEMP RES 1 ; temporarily holds value of STATUS ;-------------------------------------------------------------------------- ; Program Code ;-------------------------------------------------------------------------- Reset CODE 0x000 goto Start ;-------------------------------------------------------------------------- ; Interrupt Service Routine at 0x004 ;-------------------------------------------------------------------------- ISV CODE 0x004 retfie Intrrpt CODE ;-------------------------------------------------------------------------- ; Interrupt handler ;-------------------------------------------------------------------------- interrupt ;Save W and STATUS-registers movwf W_TEMP swapf STATUS, W ; Without changing STATUS, it's moved (will be swapped back at restore) movwf STATUS_TEMP btfss INTCON, T0IF goto interrupt_done ; It wasn't a Timer-interrupt - go to next interrupt handler timer_interrupt call ReceiveRM movf RM_temp,F ; RM_temp is non-zero if data has been received btfss STATUS,Z ; Skip next line if zero... call SendRM_RS232 ; Send data by RS232 interrupt_done swapf STATUS_TEMP, W ; Move to W, without changing flags movwf STATUS ; And restore STATUS-register swapf W_TEMP, F ; Do a swap swapf W_TEMP, W ; And swap it into W-register (moves W without changing STATUS flags) bcf INTCON, T0IF ; Clear the Timer0-flag retfie Main CODE ;-------------------------------------------------------------------------- ; Main Program ;-------------------------------------------------------------------------- Start clrf INTCON ; Disable all interrupts clrf STATUS ; Force data bank 0 clrf PORTA ; initialize port a to 0 clrf PORTB ; initialize port b to 0 bsf STATUS, RP0 ; select data bank 1 movlw b'00001101' ; moves 0x00 into the W register movwf TRISB ; tri-states portb pins to be mostly outputs, RB0&RB3 input (RB3 is RS232-RTS) movlw b'00000000' movwf TRISA ; tri-states porta pins to be all inputs ;Enable the timer bcf OPTION_REG, T0CS ; Use the internal instruction cycle clock for the timer bsf OPTION_REG, PSA ; We do not want to use our prescaler bcf OPTION_REG, PS2 ; Set Prescaler bcf OPTION_REG, PS1 ; bcf OPTION_REG, PS0 ; bcf INTCON, GIE ; Global Interrupts Disable bcf INTCON, T0IE ; Disable Timer Interrupt On Overflow bcf STATUS, RP0 ; go back to data bank 0 movlw 0x41 movwf cdc_disc movlw 0x00 movwf cdc_track movwf cdc_minute movwf cdc_second movwf cdc_mode ; 0x01=??, 0x02=CD blink, 0x04=Random, 0x08=Repeat, 0x10=Track blink, 0x20=??, 0x40=??, 0x80=??, movlw 5 ; next received byte will reset the counter to save on movwf receive_state IdleLoop call SendPacket ;10ms = 5000 instructions movlw 2 movwf IdleLoop2 IdleLoopOuter movlw 250 movwf IdleLoop1 bcf DTE_CTS ; Enable Clear To Send IdleLoopInner btfss DCE_RX call ReceiveData decfsz IdleLoop1,F goto IdleLoopInner bsf DTE_CTS ; Disable Clear To Send call ReceiveRM movf RM_temp,F ; RM_temp is non-zero if data has been received btfss STATUS,Z ; Skip next line if zero... call SendRM_RS232 ; Send data by RS232 decfsz IdleLoop2,F goto IdleLoopOuter goto IdleLoop ReceiveData ; Get data from DTE, parse. bsf DTE_CTS ; Disable Clear To Send call receive_RS232 ; movf rxbyte,W ; call send_RS232 ; Echo, debug movlw 0xFF ; test for reset-byte subwf rxbyte,W btfsc STATUS,Z goto ReceiveData_Reset ReceiveData_DisplayByte ReceiveData_CDC_Disc movlw 0x05 subwf receive_state,W btfss STATUS,Z goto ReceiveData_CDC_Track movf rxbyte,W movwf cdc_disc ReceiveData_CDC_Track movlw 0x04 subwf receive_state,W btfss STATUS,Z goto ReceiveData_CDC_Minute movf rxbyte,W movwf cdc_track ReceiveData_CDC_Minute movlw 0x03 subwf receive_state,W btfss STATUS,Z goto ReceiveData_CDC_Second movf rxbyte,W movwf cdc_minute ReceiveData_CDC_Second movlw 0x02 subwf receive_state,W btfss STATUS,Z goto ReceiveData_CDC_Mode movf rxbyte,W movwf cdc_second ReceiveData_CDC_Mode movlw 0x01 subwf receive_state,W btfss STATUS,Z goto ReceiveData_PrepareNextByte movf rxbyte,W movwf cdc_mode ReceiveData_PrepareNextByte clrf rxbyte decfsz receive_state,F goto ReceiveData_Done goto ReceiveData_Reset ReceiveData_Done return ReceiveData_Reset movlw 0x05 movwf receive_state goto ReceiveData_Done TranslateRM movwf RM_tempbyte movlw 0x54 ; track < subwf RM_tempbyte,W btfsc STATUS,Z retlw '<' movlw 0x58 ; track > subwf RM_tempbyte,W btfsc STATUS,Z retlw '>' movlw 0x60 ; Disc Down subwf RM_tempbyte,W btfsc STATUS,Z retlw 'P' ; 'P'revious movlw 0x70 ; Disc Up subwf RM_tempbyte,W btfsc STATUS,Z retlw 'N' ; 'N'ext movlw 0x48 ; Random subwf RM_tempbyte,W btfsc STATUS,Z retlw 'R' ; 'R'andom movlw 0x40 ; OFF subwf RM_tempbyte,W btfsc STATUS,Z retlw '0' ; Turn off scanning and random movlw 0x2C ; Scan subwf RM_tempbyte,W btfsc STATUS,Z retlw 'S' ; 'S'can movlw 0x52 ; Scan (OFF) subwf RM_tempbyte,W btfsc STATUS,Z retlw 's' ; 'S'can movlw 0x64 ; repeat subwf RM_tempbyte,W btfsc STATUS,Z retlw 'r' ; 'r'epeat movlw 0x1c ; Init subwf RM_tempbyte,W btfsc STATUS,Z retlw 'I' ; 'I'n movlw 0x14 ; ON subwf RM_tempbyte,W btfsc STATUS,Z retlw 'O' ; 'O'n movlw 0x20 ; Off (ping) subwf RM_tempbyte,W btfsc STATUS,Z retlw 'o' ; 'o'ff ; movf RM_tempbyte,W ; return retlw '?' ; catch-all ;-------------------------------------------------------------------------- ; SendRM_RS232 - Sends the received RM signal over RS232 to DTE ;-------------------------------------------------------------------------- SendRM_RS232 movlw 2 subwf RM_temp,W btfsc STATUS,Z goto SendRM_RS232_Repeat movlw '.' call send_RS232 goto SendRM_RS232_Done SendRM_RS232_Repeat ; movlw 13 ; call send_RS232 ; movlw 10 ; call send_RS232 movlw ':' call send_RS232 SendRM_RS232_Done movf RM_byte2,W call TranslateRM call send_RS232 clrf RM_temp return ;-------------------------------------------------------------------------- ; ReceiveRM - Receives the remote control signal pulse... ;-------------------------------------------------------------------------- ReceiveRM btfss CDC_RM return movlw d'7' ;Bits in a byte movwf RM_bitnum ;time the first low pulse ;first low is 4.5ms for a command, 2.25ms for a repeated button call RM_time_pulse ;check whether the pulse was too short to be a low pulse... movlw d'20' ; 2.0ms subwf RM_pulse_length, W btfss STATUS,C ;If it was positive... skip next line goto ReceiveRM_error ;pulse too short movf RM_pulse_length,W ;22<=w<=25 if it was a repeated button... >40 if it was a command. movlw d'40' ; 4.0ms subwf RM_pulse_length, W btfss STATUS,C ;If it was positive... skip next line goto ReceiveRM_repeat ;pulse too short to be a command (and by the previous check long enough to be a repeat) ;ok, now we have to time the pulses to retrieve the command call RM_get_byte movwf RM_byte0 call RM_get_byte movwf RM_byte1 call RM_get_byte movwf RM_byte2 call RM_get_byte movwf RM_byte3 movlw 0x01 movwf RM_temp return ReceiveRM_repeat movlw 0x02 movwf RM_temp return ReceiveRM_error movlw 0x00 movwf RM_temp ReceiveRM_done return RM_get_byte movlw 0x00 movwf RM_tempbyte movlw 0x07 movwf RM_bitnum RM_get_bit call RM_time_pulse sublw 0x0A btfsc STATUS, C ; if set, we got a 0 - else, we got a 1 goto RM_got_bit_0 ; We got a 1 - save it ; We need to save it in reverse order - this is one way to do it. movlw 0x00 movwf RM_temp movf RM_bitnum,W sublw .8 ; 8 bits in a byte. (We'll shift it 7-IR_bitnum steps to the right.) movwf RM_count bsf STATUS,C RM_got_bit_1_shift_right rlf RM_temp,F decfsz RM_count,F goto RM_got_bit_1_shift_right movf RM_temp,W iorwf RM_tempbyte,F RM_got_bit_0 movf RM_pulse_length, W sublw d'20' ;2.0 ms, longer than that is timeout btfss STATUS,C retlw 0xFF ; Timeout - bit too long (1,4ms) decfsz RM_bitnum,F goto RM_get_bit movf RM_tempbyte,W return ;Routine times the length of an RM-pulse in multiples of 100uS RM_time_pulse movlw 0x00 movwf RM_pulse_length RM_wait_for_pulse btfsc CDC_RM goto RM_wait_for_pulse RM_time_pulse_loop btfsc CDC_RM ; If there's no activity (Bit set) the pulse has ended goto RM_time_pulse_done call tenth_msecDelay incfsz RM_pulse_length, F goto RM_time_pulse_loop RM_time_pulse_done movf RM_pulse_length, W return ;-------------------------------------------------------------------------- ; SendSync - Sends synchronization bit to head unit ;-------------------------------------------------------------------------- SendSync bsf PORTA, SYNC nop nop nop nop nop nop nop nop nop nop nop nop nop nop nop nop nop nop nop bcf PORTA, SYNC nop nop nop nop nop nop nop nop nop nop nop nop nop nop nop nop nop nop nop nop return ;-------------------------------------------------------------------------- ; SendPacket - sends a display update packet to the head unit ; currently hard coded to display "CD 1 Tr 1" on head unit ;-------------------------------------------------------------------------- SendPacket call SendSync ; movlw 0xBD ; BE ; disc ; movlw 0x41 movf cdc_disc, W call SendByte ; movlw 0xFE ; track ; movlw 0x23 movf cdc_track, W call SendByte ; movlw 0xFE ; ?? ; movlw 0x45 movf cdc_minute, W call SendByte ; movlw 0xFE ; movlw 0x60 movf cdc_second, W call SendByte ; movlw 0xFF ; mode (scan/mix) ; movlw 0x00 movf cdc_mode, W call SendByte ; movlw 0x8F movlw 0x30 call SendByte ; movlw 0x7C movlw 0xC3 call SendByte call SendSync return ;-------------------------------------------------------------------------- ; SendByte - sends a byte to head unit. ; load byte to send to head unit into W register before calling ;-------------------------------------------------------------------------- SendByte movwf txreg movlw -8 bcf INTCON, GIE ; disable interrupts, timing critical BitLoop rlf txreg, 1 ; load the next bit into the carry flag ; 4.0 LOW nop nop nop nop bsf PORTA, SCLK ; SCLK high ; 1.0 HIGH nop nop nop nop bsf PORTA, STX ; load the next bit onto STX ; 0.2 HIGH nop nop nop nop btfsc STATUS, C ; 0.4 HIGH bcf PORTA, STX ; 0.6 HIGH nop nop nop nop nop nop nop nop nop nop nop nop nop ; nop bcf PORTA, SCLK ; SCLK low ; 0.2 LOW addlw 1 ; 5.2 ; 1 LOW ; nop ; nop ; nop nop nop nop nop nop nop nop nop nop nop nop nop nop nop nop nop nop btfss STATUS, Z ;5.4 ; 1 LOW goto BitLoop ;5.8 ; 2 LOW bsf INTCON, GIE ; re-enable interrupts movlw -84 ; wait 335us for head unit to store sent byte DelayLoop nop nop nop nop nop nop nop nop nop nop nop nop nop nop nop nop addlw 1 btfss STATUS, Z goto DelayLoop return END