CAN ISP on LPC5536

[Eric60]

I am interested in using CAN ISP mode using the LPC5536.  The reference manual seems to imply that CAN uses the same ISP format as the other serial ISP methods.  Does this mean that a CAN FD connection is needed? This seems to be the case because some of the ISP messages are too large for one 8 byte frame. Or is the protocol CANOpen based as was used on some other NXP devices?

Additionally, is there any existing tools or code that can use the CAN ISP mode?  I have looked at flashmagic, but it does not have a CAN option for the LPC5536.

[Eric60]

Hi Alice,

CAN-2.0 support is actually required in our case, and UART or UBS is not an option. However, based on my study of the reference manual, how the ISP protocol maps to the 8 byte CAN 2.0 frames is far from clear.  Can you provide any information about that? We don't have any problem implementing the protocol, but need the necessary details. 

Eric

[Alice_Yang]

Hello @Eric60 

Sorry, I have checked internally. There is no example using CAN ISP. You will need a CAN-USB adapter, and then refer to sections "27.11 CAN ISP," "27.3," "27.4," and "27.5" on the PC to communicate with the Boot ROM.

BR

Alice

[Eric60]

Hi Alice,

I read those sections before asking this question.  Nowhere in the those sections does it discuss how the larger ISP messages are fragmented into 8 byte CAN frames.  Can you provide any information about that? 

[Alice_Yang]

Hello @Eric60 

The larger ISP message can only be transmitted frame by frame, requiring multiple transmissions until the entire process is completed.

BR

Alice

[Eric60]

Hi Alice,

OK thank you.  Is there a particular CAN message id or range that the boot loader responds to and sends to for the ISP frames and their responses?  This information is not in the reference manual either. 

Eric

[Alice_Yang]

Hello @Eric60 

How about refer to:

BR

Alice

[Eric60]

Hi Alice,

Thanks for that information, it looks like what I need, however do you have a source document where you pulled this from?  I don't see it in the LPC5536 reference manual (Rev 3 July 2023).   I'm assuming the source document will explain how the speed parameters are used?

Eric

[Alice_Yang]

Hello @Eric60 

Sorry, the source in ROM is not public, and I also cannot access it. I found this information in the blhost documentation. A customer once configured it this way, and it worked. Therefore, I recommend it to you. You can download the doc from https://www.nxp.com.cn/docs/en/user-guide/MCUBLHOSTUG.pdf 

BR

Alice

[Alice_Yang]

Hello @Eric60 

The CAN ISP mode does not support CAN FD, it only supports CAN. Unfortunately, there is no tool available for CAN ISP mode for the LPC5536. How about using UART ISP or USB ISP mode instead?

BR

Alice

[Eric60]

Hi Alice,

Sorry I'm not used to this forum, I replied to the main topic, which see, but basically basic CAN is needed, we can't do FD for certain reasons.  Given basic CAN, the main issue now is it's not clear how the ISP protocol is transported on 8 byte frames given some of the messages are larger. Can you point me to any documentation on how this is done? I'm guessing CAN-TP, but I'd rather not guess.