I am using S32k148 CAN channel 1 and modified the sample Can Init code as below. After init I am observing Rx Error frames on the CAN bus(Usually form error, stuff error and sometimes Overload frame).
Please help in resolving this issue.
void FLEXCAN1_init(void) {
#define MSG_BUF_SIZE 4 /* Msg Buffer Size. (CAN 2.0AB: 2 hdr + 2 data= 4 words) */
uint32_t i=0;
PCC->PCCn[PCC_FlexCAN1_INDEX] |= PCC_PCCn_CGC_MASK; /* CGC=1: enable clock to FlexCAN1 */
CAN1->MCR |= CAN_MCR_MDIS_MASK; /* MDIS=1: Disable module before selecting clock */
CAN1->CTRL1 &= ~CAN_CTRL1_CLKSRC_MASK; /* CLKSRC=0: Clock Source = oscillator (8 MHz) */
CAN1->MCR &= ~CAN_MCR_MDIS_MASK; /* MDIS=0; Enable module config. (Sets FRZ, HALT)*/
while (!((CAN1->MCR & CAN_MCR_FRZACK_MASK) >> CAN_MCR_FRZACK_SHIFT)) {}
/* Good practice: wait for FRZACK=1 on freeze mode entry/exit */
CAN1->CTRL1 = 0x00DB0006; /* Configure for 500 KHz bit time */
/* Time quanta freq = 16 time quanta x 500 KHz bit time= 8MHz */
/* PRESDIV+1 = Fclksrc/Ftq = 8 MHz/8 MHz = 1 */
/* so PRESDIV = 0 */
/* PSEG2 = Phase_Seg2 - 1 = 4 - 1 = 3 */
/* PSEG1 = PSEG2 = 3 */
/* PROPSEG= Prop_Seg - 1 = 7 - 1 = 6 */
/* RJW: since Phase_Seg2 >=4, RJW+1=4 so RJW=3. */
/* SMP = 1: use 3 bits per CAN sample */
/* CLKSRC=0 (unchanged): Fcanclk= Fosc= 8 MHz */
for(i=0; i<64; i++ ) { /* CAN1: clear 32 msg bufs x 4 words/msg buf = 128 words*/
CAN1->RAMn[i] = 0; /* Clear msg buf word */
}
for(i=0; i<16; i++ ) { /* In FRZ mode, init CAN1 16 msg buf filters */
CAN1->RXIMR[i] = 0xFFFFFFFF; /* Check all ID bits for incoming messages */
}
CAN1->RXMGMASK = 0x1FFFFFFF; /* Global acceptance mask: check all ID bits */
CAN1->RAMn[ 4*MSG_BUF_SIZE + 0] = 0x04000000; /* Msg Buf 4, word 0: Enable for reception */
/* EDL,BRS,ESI=0: CANFD not used */
/* CODE=4: MB set to RX inactive */
/* IDE=0: Standard ID */
/* SRR, RTR, TIME STAMP = 0: not applicable */
#ifdef NODE_A /* Node A receives msg with std ID 0x511 */
CAN1->RAMn[ 4*MSG_BUF_SIZE + 1] = 0x14440000; /* Msg Buf 4, word 1: Standard ID = 0x111 */
#else /* Node B to receive msg with std ID 0x555 */
CAN1->RAMn[ 4*MSG_BUF_SIZE + 1] = 0x15540000; /* Msg Buf 4, word 1: Standard ID = 0x555 */
#endif
/* PRIO = 0: CANFD not used */
CAN1->MCR = 0x0000001F; /* Negate FlexCAN 1 halt state for 32 MBs */
while ((CAN1->MCR && CAN_MCR_FRZACK_MASK) >> CAN_MCR_FRZACK_SHIFT) {}
/* Good practice: wait for FRZACK to clear (not in freeze mode) */
while ((CAN1->MCR && CAN_MCR_NOTRDY_MASK) >> CAN_MCR_NOTRDY_SHIFT) {}
/* Good practice: wait for NOTRDY to clear (module ready) */
}
