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Visitor II
December 31, 2003
Question

Help needed on simple SCI program... why don't I get the same result back

  • December 31, 2003
  • 2 replies
  • 678 views
Posted on December 31, 2002 at 10:01

Help needed on simple SCI program... why don't I get the same result back

    This topic has been closed for replies.

    2 replies

    Visitor II
    December 26, 2002
    Posted on December 26, 2002 at 19:50

    code :

    .include $SetupFileName

    segment 'Ram0'

    .MB DS.B 1 ; variabele byte op adres 80h

    segment 'Rom' ; Code segment - Address defined in device file (.str)

    ; Main Code here

    .main

    call ontvang

    call wachten

    call verstuur

    call wachten

    jra main

    .ontvang

    bset SCICR2,#2 ; RDI begint te zoeken naar een startbit

    wacht btjf SCISR,#5,wacht ; Wait for reception of a new byte

    ld A,SCISR

    ld A, SCIDR

    ld MB,A

    ret ; RDRF = hoog als 1 byte ontvangen is

    .wachten

    ld X,#255

    w2 ld A,#255

    w1 dec A

    jrne w1

    dec X

    jrne w2

    ret

    .verstuur

    bset SCICR2,#3

    ld A,SCISR

    ld A,#$80

    ld SCIDR,A

    wacht1 btjf SCISR,#7,wacht1

    ld A,SCISR

    ld A,MB

    ld SCIDR,A

    wacht2 btjf SCISR,#7,wacht2

    ret

    .include $VectorFileName ; Interrupt and Vector file (.stv) included here

    end

    This program first accepts 1 byte from the PC and than sends back #80 and the received byte MB to the PC...

    The problem is that do not get the value back that I've sent to the MCU.

    What is wrong?

    thanks

    chill@mine.be
    Visitor II
    December 31, 2003
    Posted on December 31, 2002 at 10:01

    Hi,

    the btjf SCISR,#x,wacht already performs an access to SCISR. You don't need to read it once again after the btjf, maybe this can disturb the communication. It's better to put the SCI initialisation in a dedicated routine (TE,RE can be set at a time cause SCI is full duplex).

    I attach a file written in C but containing in-line assembly. Hoping it will help!

    [ This message was edited by: stef on 31-12-2002 14:32 ]

    ________________

    Attachments :

    Sci.zip : https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006I0As&d=%2Fa%2F0X0000000bW3%2F24XX0rFzE81VMmOx6ePTmPyV9ar9N14pfx0VK6fvWD8&asPdf=false