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I am reading ITM traces by SWO Printf style debugging. Can this debug information be read by a UART receiver on a FPGA ?

SGaut
Associate
 
1 ACCEPTED SOLUTION

Accepted Solutions
AntonioST
ST Employee

I do not see issues here. The SWO pin can be programmed for one between two encoding: UART or Manchester.

The data sent out in UART mode can be read by any UART receiver (pay attention to the voltage level, so you need a UART receiver at 3.3V) once you have set the proper baudrate and parity.

I never used the Manchester encoding, due to lack of proper receiver. But in a FPGA implementation the Manchester receiver could be more interesting than the UART one; the bit clock can be extracted directly from the data-stream and the RTL implementation could be far smaller than a full UART.

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3 REPLIES 3

I'd assume so, one could presumably code the FPGA to handle other protocols too.

https://developer.arm.com/docs/ddi0314/latest/serial-wire-output/swo-trace-port/physical-pin-protocol

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AntonioST
ST Employee

I do not see issues here. The SWO pin can be programmed for one between two encoding: UART or Manchester.

The data sent out in UART mode can be read by any UART receiver (pay attention to the voltage level, so you need a UART receiver at 3.3V) once you have set the proper baudrate and parity.

I never used the Manchester encoding, due to lack of proper receiver. But in a FPGA implementation the Manchester receiver could be more interesting than the UART one; the bit clock can be extracted directly from the data-stream and the RTL implementation could be far smaller than a full UART.

SGaut
Associate

Thank you for your inputs .