#int_rda happens sometimes only once

mdemuth · Joined: 16 Apr 2007 Posts: 71 Location: Stuttgart, Germany

Hi there,

I am using the compiler version 4.114

I am trying to read a stream via the uart. Each received character is supposed to create an IRQ an then it should be written into a stream (array).

The PC sends messages every 0.5s.

Sometimes everything works fine, but sometimes (50%) the programm only gets a single IRQ (I count the IRQs with the LED_3 variable) and then no more characters are received.

Has anybody an idea?

Thanks in advance,

Michael

Ttelmah · Joined: 11 Mar 2010 Posts: 19447

You are probably overflowing the buffer.
Your array, has addresses 0 to 34.
You limit the access address to 35.
When you write to location 35, you will overwrite the 'rx_buffid' variable, and failure will result.

You need:

pmuldoon · Joined: 26 Sep 2003 Posts: 218 Location: Northern Indiana

You might also want to add ERRORS to your directives:

mdemuth · Joined: 16 Apr 2007 Posts: 71 Location: Stuttgart, Germany

The "ERRORS" added to the directive solved the problem, thanks for good support!
Very Happy

Douglas Kennedy · Joined: 07 Sep 2003 Posts: 755 Location: Florida

ERRORS is almost a required parameter. It is the way it is but you could argue the parameter should have been NO_ERROR_RECOVERY indicating you wanted the interface to crash on any error. The default maybe should have been the same as adding ERRORS since that is what most would want.

RS232 is vulnerable to errors both from the environment and from its asynchronous nature. There isn't much you can do with a RS232 error except log it unless you build in ACK NAK flags so the RS232 sender can resend.