Error: Invalid op code received

Katharina

Hi Josh,

we successfully set up Bonsai with Bpod, and can now run a protocol that communicates both ways with Bonsai.

However, strangely enough we can only run the protocol on my personal tablet but not on any of the computers we are using at our rigs. We get the following error when the state machine is supposed to receive a softcode from Bonsai.

Error: Invalid op code received
Error: Invalid op code received
Error: Invalid op code received
Error: Invalid op code received
Error: Invalid op code received
Error: Invalid op code received
Error: Invalid op code received
Error: Invalid op code received
Error: Invalid op code received
Error: Invalid op code received
Error: Invalid op code received
Error: Invalid op code received
Error: Invalid op code received
Error: Invalid op code received
Error: Invalid op code received
Error: Invalid op code received
Error: Invalid op code received
Index exceeds the number of array elements. Index must not exceed 174.

Error in RunStateMachine>SetBpodHardwareMirror2ReflectEvent (line 333)
        switch BpodSystem.HW.EventTypes(thisEvent)

Error in RunStateMachine (line 175)
                SetBpodHardwareMirror2ReflectEvent(CurrentEvent);

Error in HeadFixedDetectionConfidence (line 204)
    RawEvents = RunStateMachine();

Error in run (line 91)
evalin('caller', strcat(script, ';'));

Error in NewLaunchManager>LaunchProtocol (line 779)
run(ProtocolPath);
 
Error while evaluating DestroyedObject Callback.

Our specs are:

Bpod 1.7.4
Bonsai 2.8.2
Matlab 2022b and 2023b

Do you have any ideas why this might be happening and how to troubleshoot?

Many thanks & best wishes,
Katharina

Josh

Hello Katharina,

I'm not sure why that's happening only on the rigs. I'd have to see your protocol file(s) and Bonsai workflow. Please send them to support@sanworks.io.

Thanks
Josh

Josh

Hi Katharina,

I looked over the code. I can't see an obvious issue with how it is set up.I tried opening the App serial port with a second instance of MATLAB instead of Bonsai and sending streams of 1,000 random bytes to the state machine. I confirmed that the state machine ignores any bytes that are not valid op codes from the App port, so I don't suspect that the issue is caused by a difference in the configuration of Bonsai.

Please try the following:

-Update Bpod from 1.7.4 to 1.8.0

-Remove the semicolon from line 147 of /Functions/RunStateMachine.m. The line should read:

opCodeBytes = BpodSystem.SerialPort.read(2, 'uint8');

Please share the output of the command window just prior to the crash. The values of opCodeBytes may give some clue as to what is going wrong.

If at any point you had an experimental version of the state machine firmware (e.g. to patch a bug), please try re-flashing the state machine with the current version (v23, approx. 2 years old). The command LoadBpodFirmware() makes it fairly painless.

Thanks,

Josh

Ashley

Hi Josh,

Thank you for your response. We've updated Bpod and removed the semicolon from the line in RunStateMachine. The Output of the command window is now:
`opCodeBytes =
1×2 uint8 row vector
1 1

opCodeBytes =
1×2 uint8 row vector
1 1

opCodeBytes =
1×2 uint8 row vector
94 176

Error: Invalid op code received

opCodeBytes =

1×2 uint8 row vector

249 1

Error: Invalid op code received

opCodeBytes =
1×2 uint8 row vector
0 1

Error: Invalid op code received

opCodeBytes =
1×2 uint8 row vector
1 94

Error using RunStateMachine
Unknown event code returned: 178

Error in HeadFixedDetectionConfidence (line 204)
RawEvents = RunStateMachine();

Error in run (line 91)
evalin('caller', strcat(script, ';'));

Error in LaunchManager>launch_protocol (line 843)
run(protocolPath);

Error while evaluating DestroyedObject Callback.`

Thank you!
Ashley

Josh

Hello Ashley,

From the sequence of opCodeBytes, it looks like the USB serial buffer is somehow returning out-of-frame data to MATLAB.

I have some questions about your setup:
-Are you using an external USB hub? Some hubs have caused issues like this in the past, especially from less reputable manufacturers. Whenever possible, I recommend plugging the state machine directly to the PC's USB port.

-Are you using a USB cable that is longer than 2M? USB data transfer on State Machine r2.5 and 2+ proceeds at USB2.0 high speed (480Mb/s) so these machines may be more sensitive to cable length.

-What other USB devices are connected to the PC, and how are they being used during the session? If multiple devices that draw high current are on the same internal USB hub, you may end up with unstable behavior even before the USB hub driver throws an overcurrent alert. State Machine r2.5 can draw up to ~500mA (when powering 5 ports and 3 modules) and the rated limit of USB3.0 (blue USB ports) is 900mA.

-Is the monitor connected via USB-C or Thunderbolt?

-What model of PC are you using?

-Does this error happen immediately on starting the session? Or at a random time after the session has started? If so, after approximately how many trials?

Thanks,
Josh

Ashley

Hello Josh,

Thank you for your response. We have the State Machine plugged directly into the PC’s USB port via a 0.5M cable, with the only other connected devices being a Mouse and Keyboard. The Monitor is connected to the PC via DisplayPort. We have tried The Dell OptiPlex 5070, OptiPlex 7010 Plus and a Windows Surface. Currently, the protocol only runs on the Windows Surface. The error occurs when a new event is triggered before the end of the first trial.

Thanks,
Ashley

Katharina

Hi Josh,

we solved it! It was due to a bug in our Bonsai script that lead to behaviour that constantly sent bytes to Matlab-Bpod, which some of our computers could not deal with.

Here is a link to the related thread on the Bonsai Forum https://github.com/orgs/bonsai-rx/discussions/1739

Thank you so much for your support!

Best wihses,
Katharina & Ashley

Josh

Hi all,

Great news!
This is a great point - I'll run a few tests to determine if the App serial port needs better buffering of rapid event streams. If so, it will be a firmware level change.

-Josh