Invalid error code: -11 from rtt_read()

[multiplemonomials]

Hi, I've been using pylink on a couple boards and it's been working pretty well so far! However, today one of my boards got in a bad state where RTT can't be used with it. My code has:

jlink.rtt_read(0, 1024)

and the stacktrace I get is:

  File "/home/jsmith/.local/lib/python3.10/site-packages/pylink/jlink.py", line 142, in wrapper
    return func(self, *args, **kwargs)
  File "/home/jsmith/.local/lib/python3.10/site-packages/pylink/jlink.py", line 5111, in rtt_read
    raise errors.JLinkRTTException(bytes_read)
  File "/home/jsmith/.local/lib/python3.10/site-packages/pylink/errors.py", line 38, in __init__
    message = self.to_string(code)
  File "/home/jsmith/.local/lib/python3.10/site-packages/pylink/enums.py", line 264, in to_string
    return super(JLinkRTTErrors, cls).to_string(error_code)
  File "/home/jsmith/.local/lib/python3.10/site-packages/pylink/enums.py", line 96, in to_string
    raise ValueError('Invalid error code: %d' % error_code)
ValueError: Invalid error code: -11

It looks like the J-Link DLL is returning error code -11 but this library doesn't know how to interpret that? btw, it's worked fine with this same board and script in the past.

[hkpeprah]

Sorry, I do not know what that error code is. The logs are usually a better descriptor, so if you don't have logging enabled, then I would enable it:

import logging

logging.basicConfig(level=logging.DEBUG)

[vincentdman]

Hey i have the same problem.
It seems to be a usage error. i can reproduce it by attaching a jlink to my mcu.
have the rtt_read() running in a thread.
then connect with the wrong device selected using jlink.connect.
then connect with the right device and program that device (i used a script for programming called by subprocess).
It gives the same exception traceback.
So i fixed it by first disconnecting before connecting to a new device.
I hope this helps someone