FullDuplexSerial programming help

Jared5755

I'm working with the AVRCam http://www.jrobot.net/Projects/AVRcam.html

How do you all suggest writing a routine that continuously outputs "PG" on the tx pin·until "ACK" is received on the rx pin.· I'm using FullDuplexSerial to do this.· Here's what I've come up with (doesn't work):

  rxAVRcam=8
  txAVRCam=9
  modeAVRCam=%0000
  baudrateAVRCam=115200

  AVRCam.start(rxAVRCam, txAVRCam, modeAVRCam, baudrateAVRCam)

  c1:="P"
  c2:="P"
  c3:="P" repeat until (c1=="A" and c2=="C" and c3=="K")
    AVRCam.str(string("PG"))
    c1:=AVRCam.rxcheck
    c2:=AVRCam.rxcheck
    c3:=AVRCam.rxcheck

I've left some code out from the post.· My two other serial connections work just fine.· So, it has to be either my configuration for this one, or the routine to wait for an "ACK"

Thanks a lot

StefanL38

hello jared,

take a look into the comments of fullduplexserial
as the sourcecode of fullduplexserial says

PUB rxcheck : rxbyte

'' Check if byte received (never waits)
'' returns -1 if no byte received, $00..$FF if byte

if the AVRCam does not respond "A" "C" "K" faster than the SPIN-code is running down
c1:=AVRCam.rxcheck
c2:=AVRCam.rxcheck
c3:=AVRCam.rxcheck

you might have the situation that your variables have the result
c1 = "-1"
c2 = "A"
c3 = "C"

and in the next loopturn

c1 = "K"
c2 = "A"
c3 = "C"

and then the condition is NEVER true



you could try this

PUB Pub1 | RcvdByte, AckCnt

  repeat 
    AVRCam.str(string("PG"))
    AckCnt := 0
    repeat until AckCnt => 3
      RcvdByte := AVRCam.rxcheck
      if RcvdByte == "A" or RcvdByte == "C" or RcvdByte == "K" 
        AckCnt := AckCnt + 1

or this

PUB rx : rxbyte

'' Receive byte (may wait for byte)
'' returns $00..$FF

repeat until (c1=="A" and c2=="C" and c3=="K")
    'ATTENTION !
    'its important to flush the receivebuffer !!
    'because there could be still something in the receivebuffer
    'and then the sequence "A", "C", "K" will NOT be received in "c1", "c2", "c3"

    AVRCam.rxflush 
    AVRCam.str(string("PG"))
    c1:=AVRCam.rx
    c2:=AVRCam.rx
    c3:=AVRCam.rx

best regards

Stefan


P.S.:
for debugging purposes you could have coded something
that sends the received value to another serial connection or tv_text or something like that
and THEN you would have recognized the proplem by yourself

so as a general advice:
if you don't find the error by looking at the code

code a feedback that shows you what is REALLY happening