AX12A Control with RPI4B fault [RxTxResult] There is no status packet!

Which DYNAMIXEL SDK version do you use?
- I think it's 3.7.51, I downloaded it directly using git clone today.
Which programming language/tool do you use?
- Python 3.11.2 and Raspberry PI 4B (8GB)
Which operating system do you use?
- Linux deltapi 6.1.0-rpi7-rpi-v8 1 SMP PREEMPT Debian 1:6.1.63-1+rpt1 (2023-11-24) aarch64 GNU/Linux
Which USB serial converter do you use?
- I do not use usb to serial converter because i want to connect and control on RPI-UART PORT (Rx = GPIO15 , Tx = GPIO14 ). I am trying every way for TTL communication , for example, establishing a circuit with the 71LS241N integrated circuit and GPIO18 like in datasheet, or serially connecting rx and tx directly to one wire.
Which DYNAMIXEL do you use?
- AX12-A
Have you searched the issue from the closed issue threads?
- 562
- 605
- 437
- 286
- I reviewed all closed errors containing "[RxTxResult]" and added the ones I tried above.
- Yes, i searched but there is one solution in there. The solution is check the wire, i checked my wire with multimeter, everythings okey.
- I controled parameters (ID, BAUDRATE, ...) with my Windows Pc, Dynamixel Wizard 2.0 and U2D2, there isn't problem. I even reset the AX12-A and reset it to factory settings. I'm already trying to use it at factory settings.
Please describe the issue in detail:

-When i start ping.py file response is" [TxRxResult] There is no status packet! "

I'm trying to control AX12-A on RPI-4B directly via uart pins without U2D2. But i can not found any documentation or project on robotis websites. I just found pyax12 library but it does not work. As a result, I need to control the ax12a with the uart pins on the RPI-4B. I read the ax12a doc and protocol 1 doc.

Thank you,

ROBOTIS-GIT / DynamixelSDK