MPC5777C FlexCAN CAN_ERRSR Value After Reset

[benardsetiohard]

Hi,
I am working on the FlexCan Peripheral of the MPC5777C and found that the value of the CAN_ERRSR register is set to 0x0009 0009 after resets (both hard and power reset).
This value indicates that the following ECC errors have been detected:
1. Non-correctable host access
2. Correctable error
3. Overrun on non-correctable host access
4. Overrun on correctable error

The reference manual (Rev. 8.1) states that this register should be 0x0000 0000 after reset. Does anyone have explanation to this?

My Setup:
Target HW: MPC5777C-512DS and MPC57XX Mother Board
In-Circuit Debugger: Lauterbach Trace32

I get the contents of the CAN peripheral Registers using Trace32 “On-Chip Peripherals” after running “Program Flash (prepare only)”.

Thanks,
Benard

[martin_kovar]

Hello,

 ECC on FlexCAN peripheral is enabled by default. This means, if you do not have initialized FlexCAN RAM memory and you read this memory using Lauterbach (opening peripheral Registers with appropriate address is enough), ECC error occurs.

You should initialize this memory before you read it using debugger.

For more information please see reference manual chapter 40.5.13.

https://www.nxp.com/docs/en/reference-manual/MPC5777CRM.pdf 

Regards,

Martin