Unable to connect to STM32F103 with JTAG

Environment

• Windows 10 22H2
• Python 3.12
• pyOCD 0.36.0
• DIY CMSIS-DAP v2 probe
• J-Link V9 probe
• IAR EWARM 9.5
• OpenOCD 0.12.0-4

Issue

pyOCD unable to connect to STM32F103 with JTAG, while SWD is working.

To rule out other issues all SW-HW combinations are tested (eg. CMSIS-DAP + OpenOCD in JTAG, J-Link + IAR in SWD, etc).

For both J-Link V9 and CMSIS-DAP probe pyOCD doesn't work in JTAG mode, all other combinations are working.

Error with J-Link:

$ pyocd load --target stm32f103rc -O dap_protocol=jtag -f 1000000 -a 0x20000000 "debug.bin" -v -O reset_type=hw
0000629 I Target type is stm32f103rc [board]
0000657 I DP IDR = 0x00000000 (v0 rev0) [dap]
0005668 C No cores were discovered! [__main__]

Error with CMSIS-DAP:

$ pyocd load --target stm32f103rc -O dap_protocol=jtag -f 1000000 -a 0x20000000 "debug.bin" -v -O reset_type=hw
0000648 I Target type is stm32f103rc [board]
0000741 C Unexpected ACK value (0) returned by probe [__main__]

Log

0000638 D Project directory: C:\Users\M[session]
0000638 D Project directory: C:\Users\M[session]
0000683 D CMSIS-DAP v2 probe 7C6FC9A3A144F536: protocol version 2.1.2 [dap_access_cmsis_dap]
0000685 I Target type is stm32f103rc [board]
0000731 D Running task load_svd [sequencer]
0000731 D Running task pre_connect [sequencer]
0000731 D Running task dp_init [sequencer]
0000731 D Running task lock_probe [sequencer]
0000732 D Running task get_probe_capabilities [sequencer]
0000732 D Running task connect [sequencer]
0000733 D Using JTAG wire protocol [dap]
0000741 D Sending deprecated SWJ sequence to select JTAG [swj]
0000778 D DP IDCODE read failed; resending SWJ sequence (use dormant=False) [dap]
0000778 D Sending deprecated SWJ sequence to select JTAG [swj]
0000779 D DP IDCODE read failed; resending SWJ sequence (use dormant=False) [dap]
0000779 D Sending SWJ sequence to select JTAG ; using dormant state [swj]
0000780 D DP IDCODE read failed; resending SWJ sequence (use dormant=False) [dap]
0000780 D Sending SWJ sequence to select JTAG ; using dormant state [swj]
0000781 D DP IDCODE read failed; resending SWJ sequence (use dormant=False) [dap]
0000781 D uninit session <pyocd.core.session.Session object at 0x000001CCF50B5AF0> [session]
0000782 C Unexpected ACK value (0) returned by probe [__main__]
Traceback (most recent call last):
  File "C:\Program Files\Python312\Lib\site-packages\pyocd\probe\cmsis_dap_probe.py", line 539, in read_dp
    result = self._link.read_reg(reg_id, now=now)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python312\Lib\site-packages\pyocd\probe\pydapaccess\dap_access_cmsis_dap.py", line 1086, in read_reg
    return read_reg_cb()
           ^^^^^^^^^^^^^
  File "C:\Program Files\Python312\Lib\site-packages\pyocd\probe\pydapaccess\dap_access_cmsis_dap.py", line 1080, in read_reg_cb
    res = transfer.get_result()
          ^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python312\Lib\site-packages\pyocd\probe\pydapaccess\dap_access_cmsis_dap.py", line 161, in get_result
    self.daplink.flush()
  File "C:\Program Files\Python312\Lib\site-packages\pyocd\utility\concurrency.py", line 29, in _locking
    return func(self, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python312\Lib\site-packages\pyocd\probe\pydapaccess\dap_access_cmsis_dap.py", line 885, in flush
    self._read_packet()
  File "C:\Program Files\Python312\Lib\site-packages\pyocd\utility\concurrency.py", line 29, in _locking
    return func(self, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python312\Lib\site-packages\pyocd\probe\pydapaccess\dap_access_cmsis_dap.py", line 1166, in _read_packet
    decoded_data = cmd.decode_data(raw_data)
                   ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python312\Lib\site-packages\pyocd\probe\pydapaccess\dap_access_cmsis_dap.py", line 482, in decode_data
    data = self._decode_transfer_block_data(data)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python312\Lib\site-packages\pyocd\probe\pydapaccess\dap_access_cmsis_dap.py", line 451, in _decode_transfer_block_data
    self._check_response(data[3])
  File "C:\Program Files\Python312\Lib\site-packages\pyocd\probe\pydapaccess\dap_access_cmsis_dap.py", line 374, in _check_response
    raise DAPAccessIntf.TransferError("Unexpected ACK value (%d) returned by probe" % ack)
pyocd.probe.pydapaccess.dap_access_api.DAPAccessIntf.TransferError: Unexpected ACK value (0) returned by probe

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "C:\Program Files\Python312\Lib\site-packages\pyocd\__main__.py", line 161, in run
    status = cmd.invoke()
             ^^^^^^^^^^^^
  File "C:\Program Files\Python312\Lib\site-packages\pyocd\subcommands\load_cmd.py", line 100, in invoke
    with session:
  File "C:\Program Files\Python312\Lib\site-packages\pyocd\core\session.py", line 415, in __enter__
    self.open()
  File "C:\Program Files\Python312\Lib\site-packages\pyocd\core\session.py", line 553, in open
    self._board.init()
  File "C:\Program Files\Python312\Lib\site-packages\pyocd\board\board.py", line 143, in init
    self.target.init()
  File "C:\Program Files\Python312\Lib\site-packages\pyocd\coresight\coresight_target.py", line 123, in init
    super().init()
  File "C:\Program Files\Python312\Lib\site-packages\pyocd\core\soc_target.py", line 174, in init
    seq.invoke()
  File "C:\Program Files\Python312\Lib\site-packages\pyocd\utility\sequencer.py", line 213, in invoke
    resultSequence.invoke()
  File "C:\Program Files\Python312\Lib\site-packages\pyocd\utility\sequencer.py", line 208, in invoke
    resultSequence = call()
                     ^^^^^^
  File "C:\Program Files\Python312\Lib\site-packages\pyocd\coresight\dap.py", line 467, in _connect
    connector.connect()
  File "C:\Program Files\Python312\Lib\site-packages\pyocd\coresight\dap.py", line 257, in connect
    self._idr = self.read_idr()
                ^^^^^^^^^^^^^^^
  File "C:\Program Files\Python312\Lib\site-packages\pyocd\coresight\dap.py", line 286, in read_idr
    dpidr = self._probe.read_dp(DP_IDR, now=True)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Python312\Lib\site-packages\pyocd\probe\cmsis_dap_probe.py", line 542, in read_dp
    raise self._convert_exception(error) from error
pyocd.core.exceptions.TransferError: Unexpected ACK value (0) returned by probe

Capture

I've captured the traffic of pyOCD + CMSIS-DAP and OpenOCD + CMSIS-DAP.

Open with DSView :
jtag.zip

Start with pyocd/coresight/dap.py at connect() and read_idr(), then inspect probe/cmsis_dap_probe.py alongside the jtag.zip capture. Reproduce the pyocd load command and compare its JTAG traffic with the working OpenOCD capture. Done means pyOCD can establish a JTAG connection to the STM32F103 and complete the load operation.