Today I tried to decode a CAN-Bus and was not successful so far.
Please see the attached screenshot
First, I see a lot of ripple in my measurement. Probe A is connected to CANH and GND, B is to CANL accordingly.
In the youtube-video about decoding CAN the signal is much better. is there something I have to configure ?
The decoded data is absolutely non-sense.
I also have problems to set the correct baudrate. My CAN uses 125 KBaud , which is not in the dropdown-list. Can I simply write the Baudrate into the field manually ?
Martyn wrote:Digital lines can be used for serial decoding although the signals have to adhere to the specified voltage limits.
Dr. Nicolas, one of the great things about the Picoscopes, and being able to see the serial-bus signals in the analog domain, while still decoding them, is that you get to see what's happening... warts and all. Not after it has been 'sanitized' by threshold detection, which may vary between your test device and transceivers on the CAN bus.
In your example, the analog signals are very instructive. The CANL signal looks good. Proper amplitude and offset, with low noise evident. CANH on the other hand, looks problematic. The CAN signal is riding on top of a bias offset, has lots of noise spikes, and has really poor amplitude uniformity... especially toward the end where the CRC field resides.
These factors could make it difficult for devices on your bus to properly decode the data stream, not just PicoScope. This could result in a lot of bus errors, and retries. I'd see if I could confirm those problems on CANH (zooming in would help), and track them down and remedy them, before focusing on trying to decode the data itself.