For all you guys who have time to spare <grin>, could you please take a
look at this:

I'm creating a MIDI device which has to send a program-change command.
For you guys who don't know the MIDI-protocol:
31.125 KHz serial data, 1 startbit (LOW) , 8 databits, LSB first, 1 (or
more) stopbit (high). ( ==> 1 bit == 32 cycles@4MHz clock) That's about
what the following routine's should do...
The problem is, it won't transmit program-changes with program-numbers
>99 . I just dont get it..

;This one should do the byte-sending incl. start-stopbits:

        LIST p=16c84

MIDI_Sendbyte   ;*********************  Cycles  Send MIDI byte. Data is in
Databyte
        MOVLW   0x09                    ;1      9 times. Startbit in Carry
        MOVWF   Counter                 ;1
        BCF     STATUS,0                ;1      Set startbit == logic 0
Do_serial                               ;send 8-bit serial
        CALL    Send_bit                ;28     Cycles
        RRF     Databyte,F              ;1
        DECFSZ  Counter                 ;1(2)
        GOTO    Do_serial               ;2
        BSF     STATUS,0                ;Set stopbit
        CALL    Send_bit                ;Send stopbit
        NOP
        NOP
        NOP
        NOP
        RETURN

;This one should send a singe bit, and delay for a while

Send_bit        ;*********************
        BTFSC   STATUS,0                ;2      Test carry
        GOTO    Bit_high                ;
        GOTO    Bit_low                 ;2
Bit_low
        BCF     MIDI_port               ;1
        GOTO    Bit_send                ;2
Bit_high
        NOP
        BSF     MIDI_port               ;
        GOTO    Bit_send                ;
Bit_send                                ;Total 7 cycles
        MOVLW   d'5'
        MOVWF   Delaycount
Bit_loop
        DECFSZ  Delaycount
        GOTO    Bit_loop
        NOP
        NOP                             ;18
        RETURN                          ;total : 26 w call 28

;And here's the one that sends a complete command (SHOULD send one ;) )

MIDI_prgchg     ;*********************  Program change
        MOVF    Prog_change,W
        MOVWF   Databyte
        CALL    MIDI_Sendbyte
        MOVF    Prog_nr,W
        MOVWF   Databyte
        CALL    MIDI_Sendbyte
        RETURN

;It almost has to be a timing-problem, weird thing is that byte 1 is
sent
;OK, byte 2 (program-number) not.