topic Re: FlexCAN Rx Mailbox Config to allow all CAN ID in S32K

FlexCAN Rx Mailbox Config to allow all CAN ID

soumyajit_das — Fri, 14 Aug 2020 09:35:03 GMT

MCU: S32K144

Hi,

I have imported the example project "S32K144_Project_FlexCan" in the S32 IDE. I see that the example shows how to accept data from a particular CAN ID (incoming messages). I would like to know how do we configure the registers to accept messages from any CAN ID (incoming).

I see there are three relevant register settings in FlexCAN:

1. RXMGMASK (Rx Mailboxes Global Mask register)

2. RXIMRx (Rx Individual Mask registers)

3. CAN ID field of the MB Message Box Structure

In the given example, the registers RXMGMASK is set to 0xFFFF indicating that all bits of the incoming CAN Message ID needs to be considered. Same for RXIMRx also. In this case, when you configure MB CAN ID as (say) 555, then incoming messages with CAN ID 555 will only be allowed to be received by the Rx MB.

What if I want the Rx MB to receive any CAN message bearing any CAN ID? Is the required setting 'RXMGMASK=0x0000' & 'RXIMRx=0x0000'?

If yes, then what should we put in the Rx MB CAN ID field?

NOTE:

1. I am using standard CAN ID only

2. CAN FD (Flexible Data Rate) not used

3. I am using FlexCAN0 of the MCU

Thanks

Regards

Soumyajit

Bosch, Bangalore

Re: FlexCAN Rx Mailbox Config to allow all CAN ID

danielmartynek — Mon, 17 Aug 2020 07:58:51 GMT

Hi soumyajit.das@in.bosch.com,

It was answered here:

S32K148 CAN receiver without filtering

Regards,

Daniel

Re: FlexCAN Rx Mailbox Config to allow all CAN ID

Andre_b — Wed, 10 Mar 2021 17:02:08 GMT

I read the solution proposed by Daniel but I didn't understand how to modify the example project "S32K144_Project_FlexCan" to obtain reading all message incoming with all available IDs.

In the example any message has the own ID buffer, so it can be read as below

RxID = (CAN0->RAMn[ 4*MSG_BUF_SIZE + 1] & CAN_WMBn_ID_ID_MASK) >> CAN_WMBn_ID_ID_SHIFT; /* Read ID

but without a buffer for reading ID and message, how can I read ID and datafield?

Thanks

Regards

Andrea