RT-Thread基于AT32单片机的CAN应用

1 硬件电路

2 RT-Thread驱动配置

RT-Studio中没有CAN相关的图形配置，需要手动修改board.h。在board.h的末尾，增加相关的BSP配置。

#define RT_CAN_USING_HDR
#define BSP_USING_CAN1

3 IO配置

at32_msp.c中的IO配置是PB9和PB10，掌上实验室V9实际采用的是PD0和PD1，需要修改CAN1相关的IO配置代码。

IO配置代码可以采用AT32_workbench生成，如下图所示。

at32a403a_wk_config.c中找到相关代码，修改RT-Studio中的at32_msp.c的相关代码，如下所示：

void at32_msp_can_init(void *instance)
{
#if defined (BSP_USING_CAN1) || defined (BSP_USING_CAN2)
    gpio_init_type gpio_init_struct;
    can_type *can_x = (can_type *)instance;

    gpio_default_para_init(&gpio_init_struct);
    gpio_init_struct.gpio_drive_strength = GPIO_DRIVE_STRENGTH_STRONGER;
#ifdef BSP_USING_CAN1
    if(CAN1 == can_x)
    {
        crm_periph_clock_enable(CRM_CAN1_PERIPH_CLOCK, TRUE);
//        crm_periph_clock_enable(CRM_GPIOB_PERIPH_CLOCK, TRUE);
//        crm_periph_clock_enable(CRM_IOMUX_PERIPH_CLOCK, TRUE);
//
//        gpio_init_struct.gpio_mode = GPIO_MODE_MUX;
//        gpio_init_struct.gpio_out_type = GPIO_OUTPUT_PUSH_PULL;
//        gpio_init_struct.gpio_pull = GPIO_PULL_NONE;
//        gpio_init_struct.gpio_pins = GPIO_PINS_9;
//        gpio_init(GPIOB, &gpio_init_struct);
//        gpio_pin_remap_config(CAN1_GMUX_0010, TRUE);
//
//        gpio_init_struct.gpio_mode = GPIO_MODE_INPUT;
//        gpio_init_struct.gpio_pull = GPIO_PULL_NONE;
//        gpio_init_struct.gpio_pins = GPIO_PINS_8;
//        gpio_init(GPIOB, &gpio_init_struct);

        crm_periph_clock_enable(CRM_GPIOD_PERIPH_CLOCK, TRUE);
        /* configure the CAN1 TX pin */
        gpio_init_struct.gpio_drive_strength = GPIO_DRIVE_STRENGTH_MODERATE;
        gpio_init_struct.gpio_out_type = GPIO_OUTPUT_PUSH_PULL;
        gpio_init_struct.gpio_mode = GPIO_MODE_MUX;
        gpio_init_struct.gpio_pins = GPIO_PINS_1;
        gpio_init_struct.gpio_pull = GPIO_PULL_NONE;
        gpio_init(GPIOD, &gpio_init_struct);

        /* configure the CAN1 RX pin */
        gpio_init_struct.gpio_drive_strength = GPIO_DRIVE_STRENGTH_STRONGER;
        gpio_init_struct.gpio_out_type = GPIO_OUTPUT_PUSH_PULL;
        gpio_init_struct.gpio_mode = GPIO_MODE_INPUT;
        gpio_init_struct.gpio_pins = GPIO_PINS_0;
        gpio_init_struct.gpio_pull = GPIO_PULL_NONE;
        gpio_init(GPIOD, &gpio_init_struct);

        /* GPIO PIN remap */
        gpio_pin_remap_config(CAN1_GMUX_0011, TRUE);

    }
#endif
#ifdef BSP_USING_CAN2
    if(CAN2 == can_x)
    {
        crm_periph_clock_enable(CRM_CAN2_PERIPH_CLOCK, TRUE);
        crm_periph_clock_enable(CRM_GPIOB_PERIPH_CLOCK, TRUE);
        crm_periph_clock_enable(CRM_IOMUX_PERIPH_CLOCK, TRUE);

        gpio_init_struct.gpio_mode = GPIO_MODE_MUX;
        gpio_init_struct.gpio_out_type = GPIO_OUTPUT_PUSH_PULL;
        gpio_init_struct.gpio_pull = GPIO_PULL_NONE;
        gpio_init_struct.gpio_pins = GPIO_PINS_6;
        gpio_init(GPIOB, &gpio_init_struct);
        gpio_pin_remap_config(CAN2_GMUX_0001, TRUE);

        gpio_init_struct.gpio_mode = GPIO_MODE_INPUT;
        gpio_init_struct.gpio_pull = GPIO_PULL_NONE;
        gpio_init_struct.gpio_pins = GPIO_PINS_5;
        gpio_init(GPIOB, &gpio_init_struct);
    }
#endif
#endif
}

void at32_msp_emac_init(void *instance)
{
#if defined (BSP_USING_EMAC)
    gpio_init_type gpio_init_struct;

    crm_periph_clock_enable(CRM_GPIOA_PERIPH_CLOCK, TRUE);
    crm_periph_clock_enable(CRM_GPIOB_PERIPH_CLOCK, TRUE);
    crm_periph_clock_enable(CRM_GPIOC_PERIPH_CLOCK, TRUE);
    crm_periph_clock_enable(CRM_GPIOD_PERIPH_CLOCK, TRUE);
    crm_periph_clock_enable(CRM_IOMUX_PERIPH_CLOCK, TRUE);

    gpio_pin_remap_config(EMAC_MUX, TRUE);

    gpio_default_para_init(&gpio_init_struct);
    gpio_init_struct.gpio_drive_strength = GPIO_DRIVE_STRENGTH_STRONGER;
    gpio_init_struct.gpio_mode = GPIO_MODE_MUX;
    gpio_init_struct.gpio_out_type = GPIO_OUTPUT_PUSH_PULL;
    gpio_init_struct.gpio_pull = GPIO_PULL_NONE;
    gpio_init_struct.gpio_pins = GPIO_PINS_2;
    gpio_init(GPIOA, &gpio_init_struct);

    gpio_init_struct.gpio_pins = GPIO_PINS_11 | GPIO_PINS_12 | GPIO_PINS_13;
    gpio_init(GPIOB, &gpio_init_struct);

    gpio_init_struct.gpio_pins = GPIO_PINS_1;
    gpio_init(GPIOC, &gpio_init_struct);

    gpio_init_struct.gpio_mode = GPIO_MODE_INPUT;
    gpio_init_struct.gpio_pull = GPIO_PULL_NONE;
    gpio_init_struct.gpio_pins = GPIO_PINS_1;
    gpio_init(GPIOA, &gpio_init_struct);

    gpio_init_struct.gpio_mode = GPIO_MODE_INPUT;
    gpio_init_struct.gpio_pull = GPIO_PULL_NONE;
    gpio_init_struct.gpio_pins = GPIO_PINS_8 | GPIO_PINS_9 | GPIO_PINS_10;
    gpio_init(GPIOD, &gpio_init_struct);
#endif
}

4 时钟配置

drv_can.c中给出了can的bitrate配置代码，如下所示：

#ifdef SOC_SERIES_AT32F403A
/* attention !!! baud calculation example: apbclk / ((ss + bs1 + bs2) * brp), ep: 120 / ((1 + 8 + 3) * 10) = 1MHz*/
/* attention !!! default apbclk 120 mhz */
static const struct at32_baud_rate can_baud_rate_tab[] =
{
    {CAN1MBaud,   {10 , CAN_RSAW_3TQ, CAN_BTS1_8TQ,  CAN_BTS2_3TQ}},
    {CAN800kBaud, {15 , CAN_RSAW_2TQ, CAN_BTS1_7TQ,  CAN_BTS2_2TQ}},
    {CAN500kBaud, {20 , CAN_RSAW_2TQ, CAN_BTS1_9TQ,  CAN_BTS2_2TQ}},
    {CAN250kBaud, {40 , CAN_RSAW_2TQ, CAN_BTS1_9TQ,  CAN_BTS2_2TQ}},
    {CAN125kBaud, {80 , CAN_RSAW_2TQ, CAN_BTS1_9TQ,  CAN_BTS2_2TQ}},
    {CAN100kBaud, {75 , CAN_RSAW_2TQ, CAN_BTS1_13TQ, CAN_BTS2_2TQ}},
    {CAN50kBaud,  {150, CAN_RSAW_2TQ, CAN_BTS1_13TQ, CAN_BTS2_2TQ}},
    {CAN20kBaud,  {375, CAN_RSAW_2TQ, CAN_BTS1_13TQ, CAN_BTS2_2TQ}},
    {CAN10kBaud,  {750, CAN_RSAW_2TQ, CAN_BTS1_13TQ, CAN_BTS2_2TQ}}
};

这里要特别注意的是，所有计算是基于apbclk=120MHz。要确认RT-Studio生成的代码的时钟正确，否则需重新配置时钟或修改at32_baud_rate can_baud_rate_tab表格内容。

5 RT-Thread应用示例

#include <rtthread.h>
#include "rtdevice.h"

#ifdef RT_USING_CAN

#define CAN_DEV_NAME       "can1"      /* CAN 设备名称 */

static struct rt_semaphore rx_sem;     /* 用于接收消息的信号量 */
static rt_device_t can_dev;            /* CAN 设备句柄 */

#define THREAD_PRIORITY         25
#define THREAD_STACK_SIZE       512
#define THREAD_TIMESLICE        5

static rt_thread_t tid1 = RT_NULL;
static volatile int running = 0;

static int data_buf[10];
static uint32_t data_cnt = 0;

rt_err_t lp40_recv(uint16_t id, uint8_t *msg)
{
    if(crc_high_first(msg,6)){
    }
    return RT_EOK;

}


/* 接收数据回调函数 */
static rt_err_t can_rx_call(rt_device_t dev, rt_size_t size) {
    /* CAN 接收到数据后产生中断，调用此回调函数，然后发送接收信号量 */
    rt_sem_release(&rx_sem);

    return RT_EOK;
}

static void can_rx_thread(void *parameter) {
    int i;
    //rt_err_t res;
    struct rt_can_msg rxmsg = {0};

    /* 设置接收回调函数 */
    rt_device_set_rx_indicate(can_dev, can_rx_call);

#ifdef RT_CAN_USING_HDR
    struct rt_can_filter_item items[5] = {
        RT_CAN_FILTER_ITEM_INIT(0x100, 0, 0, 1, 0x700, RT_NULL, RT_NULL), /* std,match ID:0x100~0x1ff，hdr 为 - 1，设置默认过滤表 */
        RT_CAN_FILTER_ITEM_INIT(0x300, 0, 0, 1, 0x700, RT_NULL, RT_NULL), /* std,match ID:0x300~0x3ff，hdr 为 - 1 */
        RT_CAN_FILTER_ITEM_INIT(0x211, 0, 0, 1, 0x7ff, RT_NULL, RT_NULL), /* std,match ID:0x211，hdr 为 - 1 */
        RT_CAN_FILTER_STD_INIT(0x486, RT_NULL, RT_NULL),                  /* std,match ID:0x486，hdr 为 - 1 */
        {0x555, 0, 0, 1, 0x7ff, 7,}                                       /* std,match ID:0x555，hdr 为 7，指定设置 7 号过滤表 */
    };
    struct rt_can_filter_config cfg = {5, 1, items}; /* 一共有 5 个过滤表 */
    /* 设置硬件过滤表 */
    res = rt_device_control(can_dev, RT_CAN_CMD_SET_FILTER, &cfg);
    RT_ASSERT(res == RT_EOK);
#endif
    int rx_count = 0;

    while (running) {
        /* hdr 值为 - 1，表示直接从 uselist 链表读取数据 */
        rxmsg.hdr_index = -1;
        /* 阻塞等待接收信号量 */
        if(rt_sem_take(&rx_sem, RT_WAITING_FOREVER)==RT_EOK){
            /* 从 CAN 读取一帧数据 */
            rt_device_read(can_dev, 0, &rxmsg, sizeof(rxmsg));
            /* 打印数据 ID 及内容 */
            rt_kprintf("recv %ld : id = %d, ide=%d :", ++rx_count, rxmsg.id, rxmsg.ide);
            for (i = 0; i < rxmsg.len; i++) {
                rt_kprintf(" %02x", rxmsg.data[i]);
            }
            rt_kprintf("\n");


        }
    }
}

/* 线程 1 的入口函数 */
static void thread1_entry(void *parameter) {
    struct rt_can_msg msg = {0};
    int count = 0;

    msg.id = 0x123;              /* ID 为 0x78 */
    msg.ide = RT_CAN_STDID;     /* 标准格式 */
    //msg.ide = RT_CAN_EXTID;     /* 标准格式 */
    msg.rtr = RT_CAN_DTR;       /* 数据帧 */
    msg.len = 8;                /* 数据长度为 8 */
    /* 待发送的 8 字节数据 */
    msg.data[0] = 0x00;
    msg.data[1] = 0x11;
    msg.data[2] = 0x22;
    msg.data[3] = 0x33;
    msg.data[4] = 0x44;
    msg.data[5] = 0x55;
    msg.data[6] = 0x66;
    msg.data[7] = 0x77;


    while(running) {
        /* 线程 1 采用低优先级运行，一直打印计数值 */
        rt_kprintf("send %d : id = %d, ide=%d :", ++count, msg.id, msg.ide);
        for(int i=0;i<msg.len;i++)
            rt_kprintf(" %02x", msg.data[i]);
        rt_kprintf("\n");
        rt_device_write(can_dev, 0, &msg, sizeof(msg));
        for(int i=0;i<100;i++){
            rt_thread_mdelay(50);
            if(!running)
                break;
        }
    }
    rt_device_close(can_dev);
}

int can_sample(int argc, char *argv[]) {
    rt_err_t res;
    rt_size_t  size;
    rt_thread_t thread;
    char can_name[RT_NAME_MAX];

    if (argc == 2) {
        rt_strncpy(can_name, argv[1], RT_NAME_MAX);
    } else {
        rt_strncpy(can_name, CAN_DEV_NAME, RT_NAME_MAX);
    }

    if(running){
        rt_kprintf("can_sample is running, stop it before restart!\n    can_sample_stop\n", can_name);
        return RT_ERROR;
    }

    /* 查找 CAN 设备 */
    can_dev = rt_device_find(can_name);
    if (!can_dev) {
        rt_kprintf("find %s failed!\n", can_name);
        return RT_ERROR;
    }

    running = 1;

    res = rt_sem_init(&rx_sem, "rx_sem", 0, RT_IPC_FLAG_FIFO);

    /* 以中断接收及发送方式打开 CAN 设备 */
    res = rt_device_open(can_dev, RT_DEVICE_FLAG_INT_TX | RT_DEVICE_FLAG_INT_RX);
    /* 初始化 CAN 接收信号量 */


    /* 设置 CAN 的工作模式为正常工作模式 */
    res = rt_device_control(can_dev, RT_CAN_CMD_SET_MODE, (void *)RT_CAN_MODE_NORMAL);
    //res = rt_device_control(can_dev, RT_CAN_CMD_SET_MODE, (void *)RT_CAN_MODE_LOOPBACK);
    res = rt_device_control(can_dev, RT_CAN_CMD_SET_BAUD, (void *)CAN125kBaud);

    RT_ASSERT(res == RT_EOK);
    /* 创建数据接收线程 */
    thread = rt_thread_create("can_rx", can_rx_thread, RT_NULL, 1024, 25, 10);
    if (thread != RT_NULL) {
        rt_thread_startup(thread);
    } else {
        rt_kprintf("create can_rx thread failed!\n");
    }


    if (size == 0) {
        rt_kprintf("can dev write data failed!\n");
    }

    /* 创建线程 1，名称是 thread1，入口是 thread1_entry*/
    tid1 = rt_thread_create("thread1",
                            thread1_entry, RT_NULL,
                            THREAD_STACK_SIZE,
                            THREAD_PRIORITY, THREAD_TIMESLICE);

    /* 如果获得线程控制块，启动这个线程 */
    if (tid1 != RT_NULL)
        rt_thread_startup(tid1);
    else
        rt_kprintf("start can send fail\n");

    return res;
}

int can_sample_stop(int argc, char *argv[]) {
    if(running){
        running = 0;
        //rt_sem_release(&rx_sem);
        rt_sem_detach(&rx_sem);
    }
    return RT_EOK;
}
/* 导出到 msh 命令列表中 */
MSH_CMD_EXPORT(can_sample, can device sample);
MSH_CMD_EXPORT(can_sample_stop, can device sample stop);

#endif