Use LED to indicate CAN status (IDFGH-2436)

[keelung-yang]

We want to use LED to indicate CAN controller status: busy, idle and error

Since there is an API can_get_status_info(), we know when error occurred. But how to determine busy and idle? msgs_to_tx and msgs_to_rx in can_status_info_t are not appropriate to handle busy state since there are changed quickly, laged behind can_transmit() , and hard to capture.

Also there is no interruption mentioned in CAN document.

[Dazza0]

@keelung-yang

Also there is no interruption mentioned in CAN document.

The interrupts are handled by the driver, and not exposed to the users

Since there is an API can_get_status_info(), we know when error occurred. But how to determine busy and idle? msgs_to_tx and msgs_to_rx in can_status_info_t are not appropriate to handle busy state since there are changed quickly, laged behind can_transmit() , and hard to capture.

The hardware does not provide an interrupt for when the CAN bus becomes busy or free. However, it has two readable bits to indicate whether the CAN controller is currently transmitting or receiving respectively. I can add an API to inquire these status bits. But this will mean the application level will need to periodically poll these status bits. Depending on the frequency of polling, the bus may be busy in between polling samples.

[keelung-yang]

@Dazza0 I think this solution is bad than ISR in #4527

[Dazza0]

@Dazza0 I think this solution is bad than ISR in #4527

I'm not quite sure what you mean?

[keelung-yang]

@Dazza0 I think this solution is bad than ISR in #4527

I'm not quite sure what you mean?

Polling is bad then ISR

[wanckl]

@keelung-yang Hi, As TWAI has new version driver since v5.5 and it is able to provide different ISR callbacks, dose it OK for you?

https://docs.espressif.com/projects/esp-idf/en/release-v5.5/esp32c5/api-reference/peripherals/twai.html

[keelung-yang]

@keelung-yang Hi, As TWAI has new version driver since v5.5 and it is able to provide different ISR callbacks, dose it OK for you?

https://docs.espressif.com/projects/esp-idf/en/release-v5.5/esp32c5/api-reference/peripherals/twai.html

@wanckl Yes! That's exactly what I wanted!!!

Then both CAN status indicator lights and the more accurate timestamp feature even without hardware timestamp support as described in #4527, can be implemented by ISR callback!

Although this feature is implemented after filing more than 5 years, I'm still happy when it comes true!

THANKS!

[wanckl]

@keelung-yang 🤣 timestamp is ,,, sorry, not implemented now, I'll take a look on it,

[keelung-yang]

@wanckl The timestamp is a generic and basic feature. So, it's better to be implemented in drivers but end users.

[wanckl]

@keelung-yang Hi, As timestamp support is in doing now, and LED status is able to impl already, we can close this issue now, thanks

[Alvin1Zhang]

Thanks for reporting, feel free to reopen.