Class Simple Serial / target.write & target.read not working as expected

[antragoudaras]

This might sound a bit dumb question, but I couldn’t help to ask for guidance. Without any further ado, this what bothers me the last day as I cannot find any solution to the following problem online. I had no problem programming both the scope and the target parts of the ChipWhisperer-Lite (CW1173) Two-Part Version, following the 1-Connecting to Hardware tutorial through jupyter notebook. Everything seems to be working fine when using Simpleserial object to communicate with the target, except the fact that target.read() submodule of class target seems to not work as expected as no mater how times I 've tried it returns an empty str, thus the print() function does not show anything. Oddly the target.simple_write() and target_simple_read() works without any problems. I would be glad if anyone could help on this one.!
Here is a screenshot from the jupyter Notebook, I use Ubuntu 18.04 and installed ChipWhisperer software “natively.”
Screenshot from 2021-07-21 21-45-06|690x387

P.S. I did not dealt with any problems when capruting power traces from target.
I might be a rookie in the whole ChipWhisperer toolchain but I have some strong programming knowledge especially in c and I would say that I am fairly familiar with Python.

[Alex_Dewar]

Try doing 16*“ff” instead.

Alex

[antragoudaras]

Thank you Alex, well I should have suspected/anticipated since the message length for ‘p’ is 16, otherwise the target_read thinks that the message is invalid and discards it

[Neeraja]

Hello,

I am new to Chipwhisperer and I have not quite understood why is 16*"ff’ input is working. Could you please explain about this ?
From my understanding, target.read() and write() are python functions that are used to communicate with the hardware. So does the C code really matter for target.read() to give correct output?

Also, this is what I received when giving the input as sugggested by @Alex_Dewar

could you please tell me where did I go wrong?