can.c

Explains how to communicate over the CAN bus.

/*
 * This example shows how to communicate over the CAN bus.
 */

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

/* maximal number of chars per line on lcd */
#define LCD_STRING_LENGTH   (LCD_HOR_RESOLUTION / FONT_MIN_WIDTH)

static __IO uint32_t TimingDelay;

/*
 * make a delay with the frequency of the systick
 */
void Delay(__IO uint32_t nTime) {
    TimingDelay = nTime;
    while (TimingDelay != 0);
}

void SysTick_Handler(void) {
    if (TimingDelay) {
        TimingDelay--;
    }
}

int main(void) {

    uint16_t counter = 0;
    CARME_CAN_MESSAGE CANmsg;
    char LCDmsg[LCD_STRING_LENGTH];
    uint8_t i;

    /* initialize systick with 1 kHz */
    if (SysTick_Config(SystemCoreClock / 1000)) {
        while (1);
    }

    /* initialize the LCD */
    LCD_Init();
    LCD_SetFont(&font_6x12);

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

    /* initialize the CAN message */
    CANmsg.data[2] = 0;
    CANmsg.data[3] = 0;
    CANmsg.data[4] = 0;
    CANmsg.data[5] = 0;
    CANmsg.data[6] = 0;
    CANmsg.data[7] = 0;

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

    while (1) {

        /* generate the CAN message */
        CANmsg.id = 0x100;
        CANmsg.rtr = 0;
        CANmsg.ext = 0;
        CANmsg.dlc = 2;
        counter++;
        CANmsg.data[1] = counter >> 8;
        CANmsg.data[0] = counter;

        /* send the message to the LCD */
        snprintf(LCDmsg, sizeof(LCDmsg),
                "CAN Tx: ID=0x%04lX DLC=%d D0=0x%02X D1=0x%02X", CANmsg.id,
                CANmsg.dlc, CANmsg.data[0], CANmsg.data[1]);
        LCD_Log_AddMsg(LCDmsg);
        /* send the message to the CAN bus */
        CARME_CAN_Write(&CANmsg);

        /* check if anything is received from the CAN bus */
        if (CARME_CAN_Read(&CANmsg) == CARME_NO_ERROR) {
            /* send it to LCD */
            snprintf(LCDmsg, sizeof(LCDmsg), "CAN Rx: ID=0x%04lX DLC=%d",
                    CANmsg.id, CANmsg.dlc);
            for (i = 0; i < CANmsg.dlc; i++) {
                snprintf(LCDmsg, sizeof(LCDmsg), "%s D%1u=0x%02X", LCDmsg, i,
                        CANmsg.data[i]);
            }
            LCD_Log_AddMsg(LCDmsg);
        }

        Delay(2000);
    }
    return 0;
}