LPC5534 CAN IDs and bitrate of internal Bootloader for firmware update by blhost/buspal

[cedric_starke]

Dear community,

I am currently trying to use the firmware update mechanism of the internal bootloader of the LCP5534 via the CAN interface. As far as I understand the documentation, this should be possible. However, I have not yet been able to find any documentation that includes the Rx/Tx CAN ID and bit rate of the LPC553x series.

The default values of the blhost tool with buspal are 0x321/0x123 with 4MBit. But in my tests with the controller, I have not been able to get it to work with these settings.

I am also interested in a way to change these settings. Because in our planned project we will have more than one of these controllers in the CAN bus. I don't think it will work with the same IDs.

Can anyone comment on this issue?

Best regards
Cedric

[cedric_starke · Accepted solution]

Here is a brief summary for anyone else who has the same problem.

As Alice Yang wrote, the bootloader bitrate is changed automatically. This seems to work very well. I have tested this with 125kBit and 1MBit, both worked without problems.

The CAN IDs are the default IDs of blhost/buspal:
TX (Host to LPC): 0x321
RX (LPC to host): 0x123

All communication takes place via the CAN 2.0 protocol with a maximum of 8 bytes of DLC.

As an example, a ping of the bootloader looks like this:

(000.000000)  can0  TX - -  321   [2]  5A A6

(000.001908)  can0  RX - -  123   [8]  5A A7 00 03 01 50 00 00

(000.006069)  can0  RX - -  123   [2]  FB 40

[Alice_Yang]

Hello @cedric_starke 

I will check and confirm with our internal. Then tell you after I get any update. Thanks.

BR

Alice

[Alice_Yang]

Hello @cedric_starke 

Thanks for your patience. 

From LPC553x reference manual, the default CAN seed in CAN ISP mode is 1MHZ. 

About detail description, please refer to 27.11 CAN ISP in LPC553x RM.

BR

Alice

[cedric_starke]

Hello @Alice_Yang,

after a few monkey trials with the ISP-CAN functionality, we found out that the IDs correspond to the default (TX: 0x321; RX: 0x123). Here I am still interested in the information if these IDs can be changed?

During the tests we also found out that the protocol is not CAN-FD as I thought, but it is only CAN.
I'm a bit confused about this because I'm sure I read in some document that the CAN ISP uses CAN-FD.
So far I have only tested commands like "reset", "get-property" etc, but no update file.

Can you please tell me if the update also uses only the CAN protocol and not the CAN-FD?

Best regards
Cedric

[cedric_starke]

Hello @Alice_Yang 

Thank you very much for your feedback. That clarifies the question about the speed (CAN baud rate).

But so far I could not find anything about the CAN IDs of the bootloader. Also in the CMPA there is only the possibility to change the speed, but not the IDs.

Is it possible to get some more help about the ID question?

Best regards
Cedric