external interrupt problem when receiving serial data

[NikkariB]

#USE rs232(baud=9600, PARITY=N, bits=8, xmit=PIN_B0, rcv=PIN_B0, stream = PBUS, float_high)

...

#int_ext
void pbus_isr()
{
byte data;
if (kbhit(PBUS))
{
data=fgetc(PBUS);
SerLog[ser_next_in]=data;
ser_next_in = (ser_next_in + 1) % SerLogLength;
}
}

I am using the B0 port to transmit/receive serial data from another microprocessor. My ISR above just pulls bytes into a FIFO buffer that I deal with later on. It doesn't appear that the ISR is occuring quick enough because I get garbage data coming in, but if I add a while loop around the if kbhit() statement that keeps checking the port , then my data comes in fine. It seems that as soon as it leaves the ISR, it takes too long to get back in and bytes are missed.

Where can I view/control the data that gets stacked when the ISR routine kicks in ?

What is strange is that this never used to be a problem, but I can't remember which rev of compiler I was using when I last had it running. Also, I used to have much more in the int_ext routine that parsed the message as it came in, with no problems !

(using PIC18F252 and v3.212 of compiler, although I have tried later compiler versions with no luck)

[PCM programmer]

[Mark]

Since it is an 18 series pic, you can make the external int a high priority interrupt which will save you tons of time. I would recommend that you write you own interrupt handler.

Here is an example of writing your own int handler:
http://www.ccsinfo.com/forum/viewtopic.php?t=21092&postdays=0&postorder=asc&start=15

[Humberto]

NikkariB wrote: