S12XEP100 CAN problem

bastih84 — Mon, 19 Nov 2012 14:33:12 GMT

I have a problem with a MC9S12XEP100CAG:

- CAN2 (PM4/PM5) works fine

- CAN0 (OM0/PM1) CAN1 (PM2/PM3), CAN3 (PM6/PM7) doesn't work.

The Init sequence of CAN2 and CAN0/CAN1/CAN3 is the same (see below).

CAN2 goes synchron, I can send and receive messages.

But CAN0/CAN1/CAN3 doesn't work, the CAN-bus doesn't go synchron. Transceivers are enabled (same configuration as CAN2).

I hope anybody can help.

Thanks.

Bastian

CAN2CTL0 = 0x01;

while ((CAN2CTL1 & 0x01) != 0x01)

{

}

CAN_HS_SetBRP (0x07);

CAN_HS_SetSJW (c_HS_ReSyncJumpWidth);

CAN_HS_SetPHS1 (c_HS_TimeSegment1);

CAN_HS_SetPHS2 (c_HS_TimeSegment2);

CAN2CTL1 = 0x80;

CAN_HS_SetFilter();

CAN2CTL0 = 0x00;

while ((CAN2CTL1 & 0x01) == 0x01)

{

}

CAN2RIER = 0x01;

Re: S12XEP100 CAN problem

jcdammeyer — Mon, 19 Nov 2012 14:44:55 GMT

Below is the code I've been using for several years without issues. Makes it easier to see that the initialization is exactly the same for each CAN port.

John

unsigned char *can_periph[5] = {
    &CAN0CTL0,
    &CAN1CTL0,
    &CAN2CTL0,
    &CAN3CTL0,
    &CAN4CTL0
};

void
MSCANInit(BYTE can_num, BYTE rate) {
unsigned char *can_pt;

    can_pt = can_periph[can_num];
    ActiveCANDevices |= MASK_TABLE[can_num]; // Set this CANBus as initialized.

    // If MSCAN peripheral is not in Initialization Mode, enables the Inizialization Mode Request
    if(!(can_pt[CANCTL1]&CANCTL1_INITAK_MASK))
        {
        can_pt[CANCTL0] = CANCTL0_INITRQ_MASK;
        while(!(can_pt[CANCTL1]&CANCTL1_INITAK_MASK))
            ;
        }

// Enables MSCAN peripheral and chooses Oscillator Clock(16MHz), Loop Disabled and Normal Operation
can_pt[CANCTL1] = 0x80;

    // Configures SJW = 3Tq and Prescaler = 1 (0x80 for 1Mbps), (= 2 (0x81 for 500kbps)
    can_pt[CANBTR0] = rate;
// 1Mbps with 16Mhz clock, 16Tq per bit.
    // Configures One Sample, Time Segment 1 = 12Tq and Time Segment 2 = 3Tq
    can_pt[CANBTR1] = 0x2B;

    // Disables all the Acceptance Filters by setting the masks to DON'T CARE.
    can_pt[CANIDMR_1B+0] = 0xFF;
    can_pt[CANIDMR_1B+1] = 0xFF;
    can_pt[CANIDMR_1B+2] = 0xFF;
    can_pt[CANIDMR_1B+3] = 0xFF;
    can_pt[CANIDMR_2B+0] = 0xFF;
    can_pt[CANIDMR_2B+1] = 0xFF;
    can_pt[CANIDMR_2B+2] = 0xFF;
    can_pt[CANIDMR_2B+3] = 0xFF;

    // Restarts MSCAN peripheral and waits for Initialization Mode exit
    can_pt[CANCTL0] = 0x00;
    while(can_pt[CANCTL1]&CANCTL1_INITAK_MASK)
        ;

can_pt[CANRIER] = 0x3C; // Allow status changes to set the CSCIF which signals valid
// data in the CANRFLG

}

S12 / MagniV MicrocontrollersのトピックS12XEP100 CAN problem

S12XEP100 CAN problem

Re: S12XEP100 CAN problem