Serial Timeout

SamTheMan

I want to receive a serial data.
but if it timed-out, I want to do some other tasks
if I used this function:

FUNC RX_Byte
· ·tmp var byte
·SERIN Ser_pin, Baud, tmp,__PARAM1,timeout······· ' receive a byte
·return tmp
ENDFUNC

timeout:



can I branch out to timeout lable outside the function?
do I have to add "return" at the end of timeout: ?
how can I go back to where the function was called from?



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Bean

You should NOT branch out of the function. That is bad "form", and will mess up the local variable stack.

Just put a goto after the SERIN to the RETURN.

FUNC RX_Byte 
  tmp var byte 
  SERIN Ser_pin, Baud, tmp,__PARAM1,timeout ' receive a byte 
  GOTO RX_Done 
Timeout: 
  ' timeout code here 
RX_Done: 
  return tmp 
ENDFUNC

Bean

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There is a fine line between arrogance and confidence. Make sure you don't cross it...

·

JonnyMac

I don't use timeouts very often but when I have to I include an error flag in the program and then code RX_BYTE like this:

' Use: byteVal = RX_BYTE
' -- receive "byteVal" on "RX" at "BaudMode"

FUNC RX_BYTE
  SERIN RX, BaudMode, __PARAM1, RxMaxTime, RX_Timeout
  toError = No
  GOTO RX_Exit

RX_Timeout:
  toError = Yes
  __PARAM1 = 0

RX_Exit:
  ENDFUNC

In my case __PARAM1 already has the received byte (or 0 if on a timeout) so there is no need for RETURN.