How to read Rx messages in MPC5748G dev Kit

[laxmikanthindur]

Hello, 

I am using MPC5748G Dev kit to read CAN messages from the OBD port of my car , Currently I am not able to receive any messages in the  board , because of baud rate mismatch and also configured Rx ID is only one in the example code.748g

my questions  are ;

1. How to change the baud rate ?

2. how to configure multiple read messages , if I have many Rx messages to read how to configure all of them.

Thanks in advance 

Best Regards 

Laxmikanth Indur

[martin_kovar]

Hello,

bits BUF0to31 in IFLAG register are set by hardware. When data are correctly received by message buffer, appropriate bit in IFLAG register is set. 

Please check the example code below:

https://community.nxp.com/docs/DOC-332504

I checked mpc5748g devkit and it has only one CAN transceiver. If you want to do some CAN communication, I recommend to connect boards together.

Regards,

Martin

[martin_kovar]

Hello,

about baud rate, please see the article below. It shows, how to calculate correct values for required bit rate.

https://community.nxp.com/docs/DOC-330446 

about your second question, you simply configure every message buffer you would like to use. In the code above, CAN0 message buffer 4 is configured. You can configure every MB is the same way. If you want to receive every possible ID, use ID 0 for MB configuration (for example CAN_0.MB[4].ID.B.ID_STD = 0x0;)

Regards,

Martin

[laxmikanthindur]

Hello b55689‌,

Thank you very much for the reply. it is really helpful for the understanding, However I have some more questions to you.

Boud rate calculation, is very clear. but regarding the Message Buffer selection i have some issues as below.

 As you said I just have to use the MB[x] with the required ID or by making it as zero  we can receive any possible Rx message

for example If I have to receive the Message ID 0x6FC. I just have to modify  as  CAN_0.MB[4].ID.B.ID_STD = 0x6FC;

However I have a device which is sending 0x6FC , still I am not able to receive the Messages . If I debug I have the problem at the below

While loop (), execution is getting into infinite loop, since condition is never false.

Bit BUF4TO1I is  basically to understand if this is a Interrupt or for reserved.

this particular bit is again dependent  on the CAN_MCR[RFEN]  .

Now I have a  concerns .

who is responsible for making the BUF0to31 bits to Set (logic 1), if i want to use all the buffers from 0 to 31.?

thank you very much b55689  again for your Kind support.

Best Regards

Laxmikanth Indur

[laxmikanthindur]

Hello ,

b55689‌ jiri.kral@nxp.com‌ could you please help in this.

Thank you very much in advance.