Thanks for the above suggestions.
I solved this problem. I tested the hat and pi separately, they both worked well. The echo will only show the letters but no response. The thing is Raspberry Pi changed the serial port from ttyS0 to ttyUSB2. I don't know why or how, but it worked when I changed the port name. The python script didn't work by only changing the port name, because there is a ModemMana using that port too. Need to close it for the program to run. So far haven't seen any influence from closing ModenMana.
I solved this problem. I tested the hat and pi separately, they both worked well. The echo will only show the letters but no response. The thing is Raspberry Pi changed the serial port from ttyS0 to ttyUSB2. I don't know why or how, but it worked when I changed the port name. The python script didn't work by only changing the port name, because there is a ModemMana using that port too. Need to close it for the program to run. So far haven't seen any influence from closing ModenMana.
Statistics: Posted by lhx0901 — Tue Jul 16, 2024 4:22 pm