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_CAN1if(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_CAN2if(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        5static 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_HDRstruct 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);
#endifint 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);elsert_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