Uart_sum gives wrong sum result

General
1

Greetings!
When I flash and run the bitstream uart_sum.bin for the uart_sum example using the micropython script, it gives the wrong result.
Following is a snipet of the output in Thonny. A similar image is also attached.

%Run -c $EDITOR_CONTENT

MPY: soft reboot
[shrike_flash] FPGA reset done
[shrike_flash] FPGA reset done
[shrike_fpga] Starting FPGA flash…
[shrike_fpga] flashing: uart_sum.bin
[shrike_flash] FPGA programming done.
1 + 2 = 225
2 + 3 = 4
regards,
Ranjit

wrong_output_uart_sum
wrong_output_uart_sum1313×812 96.5 KB

2

Inorder to debug the issue, I made a small change in top.v , where the instead of sum being sent back, I loopback first the first number. The first number is getting loopbacked correctly. i.e. “Value” in the logs. Further, created a different binary which loopbacks the second number instead of sum. With this, the looped back value for num2 seems different.

3

Hello @ranjitneel,

Thank you for the detailed debugging and for sharing your observations.

It would be helpful if you could create an issue in the Shrike GitHub repository with these findings, including the relevant logs and any modified top.v files or bitstreams you used for debugging.

If you are able to identify and fix the issue, we would appreciate it if you can raise a PR with the changes.

4

Thank you Upendra,
I have raised an issue with number #123 on Shrike GitHub