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efabless / caravel_mgmt_soc_litex

https://caravel-mgmt-soc-litex.readthedocs.io/en/latest/
Apache License 2.0
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UART cannot receive more than 1 character #50

Closed M0stafaRady closed 1 year ago

M0stafaRady commented 1 year ago

I'm developing test (uart_rx.py uart_rx.c) to send more than 1 character to UART. However register :ref:UART_RXTX <UART_RXTX> doesn't clear when reading from it as expected. I can't find a way to pass the first character and check the following ones.

Is there a way to clear :ref:UART_RXTX <UART_RXTX> so firmware can see the other characters, or in other word, how to pop the fifo first element so the next character can be read by the firmware?

jeffdi commented 1 year ago

Determined to be a test configuration issue. Testbench now passes.

The read from reg_uart_data needs to be followed by the uart_ev_pending register.

uart_ev_pending_write(UART_EV_RX);

The bit order for sending data to the UART was reversed.

Screenshot of successful simulation waveform.

Image