How to connect UART to kernel debug message?

[feplo...@gmail.com]

Hi

I am trying to figure out how to get "debug!()" to work with our UART hardware. Currently I am simply implementing my "transfer_buffer()" just like "send_byte()" in my Uart object. So just polling without utilizing interrupt. However, for some reasons only the first debug!() message will work. Did anyone have similar problem before?

Thanks

Yu-Chieh

[Brad Campbell]

When your uart code has finished transmitting the buffer, it needs to call the transmit complete callback. That signals to the various uart/debug layers that they can continue to send new buffers. Not calling that transmit complete callback would result in the behavior you're describing. The one catch is, however, that it is only valid to call the transmit complete callback in response to an interrupt. If you look at other uart implementations, the callback will occur once handle_interrupt() is called. So, in Tock you need to have an asynchronous uart implementation to correctly implement the driver.

-Brad

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[feplo...@gmail.com]

Hi Brad

Thanks for the information. Tock kernel debug message seems to work properly(at least much better) after UART interrupt was setup.

Yu-Chieh