CAN Appnote for STM32 Devices

[ZAlem]

Good afternoon Clive et al,

I need a functional description that discusses the data flow of CAN data. Reference manual does not have a detailed description.

If no additional documentation is available, are there documents other than the reference manual and datasheet that I need to consult?

Please send me a link(s) if available?

Thank you in advance for your help and support,

Ziggy

[Tesla DeLorean]

I used the Reference Manual and a pragmatic understanding of CAN bus traffic.

I've published several working SPL examples for F2 and F4 boards. And explained CAN Filters more times than I can count.

A quick Google yielded

http://www.keil.com/appnotes/files/apnt_236.pdf

https://www.st.com/content/ccc/resource/training/technical/product_training/de/ee/37/c6/60/9c/45/a5/STM32L4_Peripheral_CAN.pdf/files/STM32L4_Peripheral_CAN.pdf/jcr:content/translations/en.STM32L4_Peripheral_CAN.pdf

https://jeelabs.org/2018/canbus-intro/

[ZAlem]

Good evening Clive,

Thanks again for the great support. There might be a method to the documentation of how ST capture details that I am not used to. I've experience with other manufacturers and this is a bit different. Anyway, I will look forward to your appnote and info you provided me. Thanks again for your prompt response and great support.

Best regards,

Ziggy

[Amel NASRI]

Hello @ZAlem​ ,

Could you please share more details on what you expect from such application note compared to what we have in reference manual?

Are you expecting a detailed description of CAN protocol when you say "I need a functional description that discusses the data flow of CAN data."?

-Amel

[ZAlem]

Good morning Amel,

Thank you for the opportunity. The reference manual is very huge. So, you expect the information you require will be contained in a chapter or so. For each peripheral that I consult, I was expecting to see all the information related to that peripheral contained in a chapter that discusses that peripheral. This include, clock information, register description, functional description, high level bus transaction to display data communication and finally a sample code that would tie everything up together. Sample code could be initialization of a clock and some of the main registers as well as some made up data transfer. I do not expect to find protocol information since that is part of a standard and only necessary information pertaining the spec to highlight implementation specific information. This is how most of the semi conductor companies are documenting peripherals.

I understand ST is different and as of now, I am trying to figure out as to gather all the necessary information. I am sure they have their good reasons and do not want to speculate. I see most of the data that is required partly in the reference manual and partly in the datasheet. What I think is missing is a functional description which could be an example that captures the clock and registers configuration as well as transmit and receive data transaction. This is going to bring all the necessary registers required to be programmed with the application to get a peripheral going.

It seems mostly that users are using HAL which is abstracting the actual interface with the hardware and for someone who is not using one of the HAL supported, it takes a whole lot of effort to bring all together. I understand that and I thing that is great for many users who do not have the need for the hardware programming.

That said, an appnote by the manufacturer that shows an example of implementation of the peripheral operation always complements the manuals and allows to further emphasize the peripheral function and address many user's questions.

An appnote, in this case, that is not HAL specific is important to the underlying implementation and operation of the peripheral. That was what I was looking for. Going through a 3rd party appnote to gain more info by finding out their configuration is great but that requires additional time get to know their HAL in this case. So an appnote from the manufacturer would be a great addition to the Reference manual to show case the functional description of the peripheral. It will reduce the support required by your company and also showcase your device for design wins.

Thank you and best regards,

Ziggy