topic Re: The first CAN message received after MCU power-up is always empty. in S32K

The first CAN message received after MCU power-up is always empty.

Hanz — Mon, 05 May 2025 06:57:44 GMT

Hi Expert,

The first CAN message received after MCU power-up is always empty.

Below it the CAN init and it's call back function.

void CAN0_init() {

IntCtrl_Ip_EnableIrq(FlexCAN0_0_IRQn);

IntCtrl_Ip_EnableIrq(FlexCAN0_1_IRQn);

IntCtrl_Ip_EnableIrq(FlexCAN0_2_IRQn);

IntCtrl_Ip_InstallHandler(FlexCAN0_0_IRQn,&CAN0_ORED_IRQHandler,NULL_PTR);

IntCtrl_Ip_InstallHandler(FlexCAN0_1_IRQn,&CAN0_ORED_0_31_MB_IRQHandler,NULL_PTR);

IntCtrl_Ip_InstallHandler(FlexCAN0_2_IRQn,&CAN0_ORED_32_63_MB_IRQHandler,NULL_PTR);

FlexCAN_Ip_Init(CAN_DEV_INSTANCE, &FlexCAN_State0, &FlexCAN_Config0);

FlexCAN_Ip_SetRxMaskType(CAN_DEV_INSTANCE,FLEXCAN_RX_MASK_INDIVIDUAL);

FlexCAN_Ip_SetRxIndividualMask(CAN_DEV_INSTANCE,RX_MB_IDX,0);

FlexCAN_Ip_SetStartMode(CAN_DEV_INSTANCE);

FlexCAN_Ip_ConfigRxMb(CAN_DEV_INSTANCE, RX_MB_IDX, &rx_info, MSG_ID);

FlexCAN_Ip_Receive(CAN_DEV_INSTANCE, RX_MB_IDX, &rxData, FALSE); //clear redundancy data

/* Start Receive CAN Data */

( void ) FlexCAN_Ip_RxFifo(CAN_DEV_INSTANCE, &Can0Rx_isr);

( void ) FlexCAN_Ip_SetErrorInt(CAN_DEV_INSTANCE, FLEXCAN_IP_INT_BUSOFF, TRUE);

}

void flexcan0_Callback(uint8 instance, Flexcan_Ip_EventType eventType, uint32 buffIdx,

const Flexcan_Ip_StateType *flexcanState)

{

switch(eventType)

{

case FLEXCAN_EVENT_RX_COMPLETE:

FlexCAN_Ip_Receive(CAN_DEV_INSTANCE, RX_MB_IDX, &Can0Rx_isr, FALSE);

break;

}

RTD version:

/*==================================================================================================

* Project : RTD AUTOSAR 4.7

* Platform : CORTEXM

* Peripheral : FLEXCAN

* Dependencies :

* Autosar Version : 4.7.0

* Autosar Revision : ASR_REL_4_7_REV_0000

* Autosar Conf.Variant :

* SW Version : 5.0.0

* Build Version : S32K3_RTD_5_0_0_D2408_ASR_REL_4_7_REV_0000_20241002

================================

Re: The first CAN message received after MCU power-up is always empty.

PetrS — Mon, 05 May 2025 12:17:56 GMT

Hi,

I am not aware of situation which can lead to behavior you wrote.
Are you able to share full simplified project for testing and specify the bus condition and behavior for the issue (message send from other node, rxbuffer content after receiving, etc)?
Your code includes RXFIFO_receive calling. How the RXFIFO is used/configured?

BR, Petr

Re: The first CAN message received after MCU power-up is always empty.

Hanz — Tue, 06 May 2025 01:42:44 GMT

Hi Petr,

I can't share the simple project with you, but here is the FlexCAN configuration.

The test environment is as follows: the MCU's CAN_H is connected to the PCAN's CAN_H, and CAN_L is connected to CAN_L.

A CAN message is sent via PCAN Viewer right after the MCU powers up. Then we check whether the message is received.

Could this be an RX FIFO configuration issue?

Thanks.

Re: The first CAN message received after MCU power-up is always empty.

PetrS — Tue, 06 May 2025 09:08:10 GMT

Hi,

a FlexCAN config does not show RXFIFO is enabled so why FlexCAN_Ip_RxFifo is called then?
For the first message do you see callback is called and rxbuffer is empty/wrong or callback is not called at all?
Did you do any measurement to be sure all init is done before message came? Do you see any kind of error detected?

BR, Petr