--=-KboKlRHil05vI/ExyFYg
Content-Type: text/plain
Content-Transfer-Encoding: 7bit

I have the following program that is supposed to, at reset, send the
character "A" at 9600 bit/sec on the PB7 pin.
I do not get anything back :(
Any ideas ?

Amaury

        ;; program to send 'A' on the serial port
        ;;
        list    f=INHX8M, p=16F84
        __config        0x1ff9

        ;; status register
status  equ     0x07            ; status register
rp0     equ     5               ;
carry   equ     0               ; the carry bit

        ;; port B configuration
portb   equ     0x06            ; I/O port B
serio   equ     7               ; the serial i/o is RB7
sda     equ     5               ; SDA is RB5
scl     equ     4               ; SCL is RB4

trisb   equ     0x86            ; trisb is the direction register for
port B

        ;; serial bus buffers/counters
sobuf   equ     0x0c            ; serial output buffer
sibuf   equ     0x0d            ; serial input buffer
sctr    equ     0x0e            ; counter for bits to output to serial
port
delay   equ     0x0f            ; wait counter for serial i/o

        ;; beginning of the program
        ;; jump over the interrupt vector
        org     0
init    goto    start

        ;; interrupt vector
        ;; do nothing
        org     4
intr    retfie                  ; do nothing if an interuption occurs

start   bcf     status, rp0     ; select bank 0
        clrf    portb           ; clears port B
        bsf     status, rp0     ; select bank 1
        movlw   0x00            ; all pins in output position
        movwf   trisb           ; sets direction for all pins to
"output"
        movlw   'A'             ; character 'A'
        movwf   sobuf           ; stores the character in the buffer
        call    ssbyte          ; sends a byte
        sleep                   ; stops the program

        ;; sends a byte
        ;; gets the byte in the W register
        ;; output pin is RB7
        ;; first, send the start bit
ssbyte  btfsc   portb, serio    ; tests if the serial i/o was up
        goto    stbit           ; no, create a stop bit
        bsf     portb, serio    ; sets portb so that we have a stop bit
        call    swbit           ; waits for the lenght of a bit
stbit   movlw   8               ; 8 bits to send
        movwf   sctr            ; move to counter register
        bcf     portb, serio
        call    swbit
        ;; first, shift the buffer through the carry
sbitlp  rrf     sobuf, 1        ;
        btfsc   status, carry   ; test the carry
        goto    sbset           ; the bit is set
        ;; the bit is clear
        bcf     portb, serio    ; clear the bit
        goto    sbwait          ; go to the wait call
        ;; the bit is set
sbset   nop                     ; cycle
        bsf     portb, serio    ; set the bit
sbwait  call    swbit           ; wait
        ;; decrement the counter
        decfsz  sctr, 1         ; one bit done !
        goto    sbitlp          ; no, still some bits
        ;; TODO : now, insert parity
        ;; stop bit
        bsf     portb, serio    ; stop bits are up
        call    swbit           ; wait to the end of the bit
        return                  ; do nothing at the moment

        ;; wait for 104 cycles (1 bit)
        ;; 7 cycles used
swbit   movlw   0x2E            ; load counter
        movwf   delay           ;
        ;; 9 cycles used. 95 remaining
swblp   decfsz  delay, 1        ; decrement counter     +1
        goto    swblp           ; loop                  +1
        return                  ; this is supposed to wait for 1/9600 of
a second
        end




--=-KboKlRHil05vI/ExyFYg
Content-Type: application/pgp-signature
Content-Transfer-Encoding: base64

LS0tLS1CRUdJTiBQR1AgU0lHTkFUVVJFLS0tLS0KVmVyc2lvbjogR251UEcgdjEuMC42IChHTlUv
TGludXgpCkNvbW1lbnQ6IEZvciBpbmZvIHNlZSBodHRwOi8vd3d3LmdudXBnLm9yZwoKaUQ4REJR
QTdnQm5BT3hkQ3UxdzZZMzhSQXRCckFKOW10MGVydENnZ0h1OWoyS2ZoYlhQSHRSZ2lhUUNnc1hk
dApIOW9ESm55eFBuNld4eEZlYUNvZ21xbz0KPWJDUjEKLS0tLS1FTkQgUEdQIFNJR05BVFVSRS0t
LS0tCg==

--=-KboKlRHil05vI/ExyFYg--

--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu