ESP32-WROOM32E - V3 - Canbus speeds halved?

rixst3r
Posts: 2
Joined: Tue May 12, 2020 11:05 am

ESP32-WROOM32E - V3 - Canbus speeds halved?

Postby rixst3r » Tue May 12, 2020 11:12 am

Hello! I used an existing circuit design and software code but swapped from an older module to the new V3 core 32E module. All was well until I realized all my CAN timing was creating bus speeds half of the other module. If I input the settings for 500kbps working on the older modules I end up with 250kbps on the 32E

Is this by design, or a bug? I noticed a note in the ECO v3 release docs about a new canbus speed, but I didn’t see any mention of changes in timings for previously supported speeds. Before I make a workaround, I wanted to see if this was expected behavior or a bug?

Thanks!

ESP_Dazz
Posts: 193
Joined: Fri Jun 02, 2017 6:50 am

Re: ESP32-WROOM32E - V3 - Canbus speeds halved?

Postby ESP_Dazz » Wed May 13, 2020 8:26 am

Not a bug but a feature. ESP32 ECO3 added a configurable bit that will cause CAN bus speeds to be halved (i.e thus allows for lower bit rates).

However, by default this feature should be disabled by the driver (see this commit). Which version of ESP-IDF are you using? Do you have a copy of your sdkconfig?

rixst3r
Posts: 2
Joined: Tue May 12, 2020 11:05 am

Re: ESP32-WROOM32E - V3 - Canbus speeds halved?

Postby rixst3r » Wed May 13, 2020 11:32 am

Thank you, that solved it for me. I had attempted to enable the wake-up interrupt in my code even though it was not supported... now that ECO V3 uses that bit for the divider, it was doing its job.

Lesson learned—respect the reserved bits.

Thanks!

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