Is there an application guide for a CAN based MC33665 system?

[Poley]

Hi all,

I am currently migrating from a MC33664 architecture to the MC33665 to open up what BCC's I use. I would like the use the CAN MC33665 instead of the SPI version so I can use it without an MCU for initial testing.

Is there any guide to how to request measurements for all BCC's on TPL chain and read all boards data like cell voltages, temperatures and current for example? I can't seem to find anythign that explicitly states this unless I am missing the obvious?

Thanks in advance!

[Poley]

Oh is it just this, or does this not work for the CAN based system:

[JozefKozon]

Hi Matthew,

yes, this also works for CAN FD. You need the CAN to TPL transceiver. MC33665A CAN to TPL version.

With Best Regards,

Jozef

[Poley]

Hi Jozef,

Ah ok, so I can send 1 CAN message that sets DATA to 15 and register address of 0x32 then I should recieve 15 CAN messages in a burst without sending another one contacining all 14 cells and the stack voltage?

Thanks!

[JozefKozon]

Hi Poley,

please check a BCC's full datasheet you are using. If you are using MC33774A, please refer to Table 59. for global communication settings and to section 12.1.69 for global balancing configuration and also following pages in the full MC33774A datasheet. You can download it from the MC33774A product page, under the secure files.

With Best Regards,

Jozef

[Poley]

Hi Josef,

I am using MC33771C currently

Thanks!

[JozefKozon]

Hi Poley,

thank you for clarification of the part number. In this case, please refer to the section 10. in the MC33771C full datasheet.

Please download the full MC33771C datasheet from the MC33771C product page, under the secure files.

With Best Regards,

Jozef

[Poley]

Hi Jozef,

Sorry, I wasn't talking about a global command. More a signle BCC command that requests multiple register reads rather than just 1 at a time. I know it can be done with SPI but unsure whether this is also possible on the MC33665 CAN based communication?

Also, I have just recieved the FRDM665CANFDEVB development board. Is there any quick example to show CAN based TPL? I have this board and a MC33771C board to communicate with.

Thanks!

[JozefKozon]

Hi Matthew,

please see below an answer from an application team regarding the MC33771C + MC33665A CAN FD communication. Please find the UM11748 attached.

DESCRIPTION

Below are few boards based on MC33775A which are helpful for successful demo.
RD33775ACNCEVB: https://www.nxp.com/design/designs/hvbms-centralized-cell-monitoring-unit-using-can-fd-with-mc33775a...

RD33775ACNTEVB : https://www.nxp.com/design/designs/hvbms-centralized-cell-monitoring-unit-using-etpl-with-mc33775a-c...

"UM11748 - MC33665A_CCMU_Demo user manual" is available as part of the download package. As mentioned in section 2, "Goal of MC33665A_CCMU_Demo is to utilize the features of CANoe to communicate with MC33665A in extracting the cell voltages and temperatures from MC33775A BCCs designed by NXP ".

We had build the demo to support MC33775A BCC devices only. We didnt plan or built demo for MC33771C files, request your support to convey the message to end customer. Please feel free to share the EVB's or reference design based on MC33775A for successful demo to customer.

With Best Regards,

Jozef

[Poley]

Is it possible to modify this to work with the MC33771C?

[JozefKozon]

Hi Poley,

I guess this would be possible. However the MC33771C was released long time before the MC33665A with CAN interface. Therefore the software was created for the MC33775A. Unfortunately our SW team didn't create any application note or any other document how to apply the mentioned software for the MC33771C. I think it would be easier to purchase the RD33775ACNCEVB or RD33775ACNTEVB and evaluate the software on this boards. 

I apologize for inconvenience. 

With Best Regards,

Jozef

[JozefKozon]

Hi Matthew,

please download the AN13910 from the MC33665A product page, under the secure files. 

There is a section 3.2.3 CAN Interface to BMU. Further under the section 3.24 is a link to AN13281 HVBMS daisy chain communication guide.

It will take you to the document to download. This two documents could be very useful for you.

With Best Regards,

Jozef

[Poley]

Hi Jozef,

That is great, thank you! I didn't have access to that file at the time so that's why I couldn't find anything on this.

Just as a follow up, because CAN is slower than SPI and the TPL communication, are there any software tips on how to read multiple BCC's efficiently rather than just using 1 CAN command at a time? If not, this feels like data measurements would take a very long time to retreive. Especially as all data would be returning on the same CAN ID everytime.

I hope that makes sense!

Thank you!