I'm using a MAX14830 quad UART under FreeRTOS with my own driver.
So far I have failed to run a test sequence that would raise the Rx overrun flag.
The test sequence basically sends 136 bytes into the Rx of one UART with the software not reading the RHR. After 128 bytes the Rx FIFO is expected to be full. 128 bytes are successfully read, and then the FIFO is viewed as empty as expected. However, the extra 8 bytes that were sent did not set the Rx overrun status.
I've tried polling the Line Status Register, as well as triggering an interrupt on Rx errors, but failed to get this Rx overrun status set or generate an interrupt.
Other tests are successful in getting the other error conditions: parity, framing, break. The interrupt on error occurs for all error conditions but the Overrun.
Any hint about how to get this guy set when an overrun occurs?