MQX won't detect UART data present

snapcount · ‎11-16-2015

Greetings!

I'm using the _io_fstatus() function to wait for a byte to show up on ittyc: on a K11 part. I checked the 'D' register and can see the byte is reaching the micro but for some reason the call to _io_fstatus() is never returning true. I have tried this on other UARTs on the same part and it works great. I was wondering if anyone has any ideas or a list of things to check in order for this method to work correctly. This is MQX v4.01.

Thanks in advance!

Roy

snapcount · ‎11-17-2015

Sorry to reply to my own post but I have some new information and I thought it may help someone to help me. I'm not sure this is an MQX issue anymore. In the ISR it is checking for UART2_S1[RDRF] to be set. This is not happening (based on register inspection).

From what I gather, the FIFO on UART2 of the K11 is 1 byte in depth. I read the datasheet regarding RWFIFO[RXWATER] setting and how it affects RDRF. I have RXWATER set to 0x01 but the datasheet says this value must be set *less than* the FIFO size for the UART and greater than zero. This would be impossible for a FIFO 1 byte deep. In any case any help is appreciated, I must be mistaken about something.

Roy