can_acceptancefilter.c

Explains how to set a acceptance filter on the CAN transceiver.

/*
 * This example shows how to set a acceptance filter on the SJA100 CAN
 * transceiver.
 */

#include <stm32f4xx.h>
#include <carme.h>
#include <can.h>

CARME_CAN_ACCEPTANCE_FILTER af;

/* initialize the Array with accepted IDs */
uint8_t acceptedId[] = {
        0x10,
        0x20,
        0x30
};

int main(void) {

    uint8_t arrayIndex;

    /* initialize the SJA1000 chip */
    CARME_CAN_Init(CARME_CAN_BAUD_250K, CARME_CAN_DF_RESET);

    /*
     * Initializing of the Acceptance Filter. This Code initializes the filter
     * to 0xXZX where X is don't care and Z is the value in the acceptedId
     * array.
     */
    af.afm = MODE_SINGLE;   /* Single filter */

    /* unmask the important bits by setting them to Zero */
    af.amr[0] = 0xe1;       /* unmask bit 4 - 8                             */
    af.amr[1] = 0xff;       /* the lower 4 bit should always be masked      */
    af.amr[2] = 0xff;       /* don't care in Mode with normal id length     */
    af.amr[3] = 0xff;       /* don't care in Mode with normal id length     */

    /* set the bits which have to be high */
    af.acr[0] = acceptedId[arrayIndex] >> 3; /* set the accepted bits 4 - 8 */
    af.acr[1] = 0x00;
    af.acr[2] = 0x00;       /* don't care in Mode with normal id length     */
    af.acr[3] = 0x00;       /* don't care in Mode with normal id length     */

    /* set the AF */
    CARME_CAN_SetAcceptaceFilter(&af);

    /* set the SJA1000 chip in running mode */
    CARME_CAN_SetMode(CARME_CAN_DF_NORMAL);

    while (1) {
    }
    return 0;
}