Hi all

I have an application that is basically dumb IO that's sits there on a RS485 bus and listens for a message that is addressed to it and then performs the command that is embedded in the message.

Basically in the main() function I call a get frame function which in turn calls a get byte function (shown below)

If a byte comes in the port then it is detected when RI becomes active, if it is in the middle of a meesage then it must occur within a certain time period to allow for intercharacter timeouts, (the length of the frame is embedded in the message)

This all works well for a period of time and then I stop getting the RI becoming active when the byte comes in.

I am not using the serial interrupts it is all polling driven.

has anyone seen this before? any tips?

any help is appreciated.


Regards

Marshall Brown


The Receiving Function:
byte GetByte(void)
{
byte c;
word counter;

Error = FALSE;//Clear Error Flag
counter = 0;
//Clear TimeOut counter
while (!RI)
{
if(FrameStatus == STARTED)counter++;
if(counter > 1000){Error = TRUE;return(0);} //Time for receiving 1 byte + 20%
}
c = SBUF;
RI = 0;

return(c);
}