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Unhandled Exception when performing _io_fflush() to UART

Question asked by panpwr on Jan 23, 2013
Latest reply on Jan 29, 2013 by panpwr



I try to sent a short string (4 bytes) to UART, at the following way:

_io_write(uart_ch, stream_ptr, stream_len); //<== After performing this line, only 2 bytes are actually transffered to UART

_io_fflush(uart_ch);  // <== Unhandled Exception


I use Keil uVision4 (4.60) IDE. It doesn't matter how I open the UART - it's the same result (either XON_XOFF or NON_BLOCKING modes).


When I check the debug->MQX->Check for errors, I see under "Tasks": "Unhandled Exception", the Task ID, and the Task Descriptor (by the way - it's not the task that issued the UART write action, but a different task).


1. Why doesn't it write all the bytes at once?

2. What can cause the "Flush" action to behave like that?

3. What can I do with the exception information? How can I get to the bottom of the problem (I have very little knowledge of MQX debugging...)