在applicantions文件夾下新建test_can.c，內容如下：

/*

程序清單：這是一個 CAN 設備使用例程
例程導出了 can_sample 命令到控制終端
命令調用格式：can_sample bxcna
命令解釋：命令第二個參數(shù)是要使用的 CAN 設備名稱，為空則使用默認的 CAN 設備
程序功能：通過 CAN 設備發(fā)送一幀，并創(chuàng)建一個線程接收數(shù)據(jù)然后打印輸出。
/
#include "can_dewen.h"
#include
#include "rtdevice.h"
#define CAN_DEV_NAME "bxcan" / CAN 設備名稱 /
static struct rt_semaphore rx_sem; / 用于接收消息的信號量 /
static rt_device_t can_dev; / CAN 設備句柄 /
/ 接收數(shù)據(jù)回調函數(shù) /
static rt_err_t can_rx_call(rt_device_t dev, rt_size_t size)
{
/ CAN 接收到數(shù)據(jù)后產生中斷，調用此回調函數(shù)，然后發(fā)送接收信號量 /
rt_sem_release(&rx_sem);
return RT_EOK;
}
int can_send(rt_uint32_t humi,rt_uint32_t temp)
{
struct rt_can_msg msg = {0};
rt_err_t res;
rt_size_t size;
msg.id = 0x78; / ID 為 0x78 /
msg.ide = RT_CAN_STDID; / 標準格式 /
msg.rtr = RT_CAN_DTR; / 數(shù)據(jù)幀 /
msg.len = 8; / 數(shù)據(jù)長度為 8 /
/ 待發(fā)送的 8 字節(jié)數(shù)據(jù) /
msg.data[0] = (uint8_t)(temp/100);
msg.data[1] = (uint8_t)(temp%100);
msg.data[2] = (uint8_t)(humi/100);
msg.data[3] = (uint8_t)(humi%100);
msg.data[4] = 0x44;
msg.data[5] = 0x55;
msg.data[6] = 0x66;
msg.data[7] = 0x77;
/ 發(fā)送一幀 CAN 數(shù)據(jù) /
size = rt_device_write(can_dev, 0, &msg, sizeof(msg));
if (size == 0)
{
rt_kprintf("can dev write data failed!n");
}
return res;
}
static void can_rx_thread(void parameter)
{
int i;
rt_err_t res;
struct rt_can_msg rxmsg = {0};
/ 設置接收回調函數(shù) /
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, 0, 0x700, RT_NULL, RT_NULL), / std,match ID:0x1000x1ff，hdr 為 - 1，設置默認過濾表 /
RT_CAN_FILTER_ITEM_INIT(0x300, 0, 0, 0, 0x700, RT_NULL, RT_NULL), / std,match ID:0x3000x3ff，hdr 為 - 1 /
RT_CAN_FILTER_ITEM_INIT(0x211, 0, 0, 0, 0x7ff, RT_NULL, RT_NULL), / std,match ID:0x211，hdr 為 - 1 /
RT_CAN_FILTER_STD_INIT(0x486, RT_NULL, RT_NULL), / std,match ID:0x486，hdr 為 - 1 /
{0x555, 0, 0, 0, 0x7ff, 7,} / std,match ID:0x555，hdr 為 7，指定設置 7 號過濾表 /
};
struct rt_can_filter_config cfg = {5, 1, items}; / 一共有 5 個過濾表 /
/ 設置硬件過濾表 /
res = rt_device_control(can_dev, RT_CAN_CMD_SET_FILTER, &cfg);
RT_ASSERT(res == RT_EOK);
#endif
while (1)
{
/ hdr 值為 - 1，表示直接從 uselist 鏈表讀取數(shù)據(jù) /
rxmsg.hdr = -1;
/ 阻塞等待接收信號量 /
rt_sem_take(&rx_sem, RT_WAITING_FOREVER);
/ 從 CAN 讀取一幀數(shù)據(jù) /
rt_device_read(can_dev, 0, &rxmsg, sizeof(rxmsg));
/ 打印數(shù)據(jù) ID 及內容 /
rt_kprintf("ID:%x", rxmsg.id);
for (i = 0; i < 8; i++)
{
rt_kprintf("%2x", rxmsg.data[i]);
}
rt_kprintf("n");
}
}
int can_sample(void)
{
struct rt_can_msg msg = {0};
rt_err_t res;
rt_size_t size;
rt_thread_t thread;
char can_name[RT_NAME_MAX];
rt_strncpy(can_name, CAN_DEV_NAME, RT_NAME_MAX);
/ 查找 CAN 設備 /
can_dev = rt_device_find(can_name);
if (!can_dev)
{
rt_kprintf("find %s failed!n", can_name);
return RT_ERROR;
}
/ 初始化 CAN 接收信號量 /
rt_sem_init(&rx_sem, "rx_sem", 0, RT_IPC_FLAG_FIFO);
/ 設置 CAN 通信的波特率為 500kbit/s /
res = rt_device_control(can_dev, RT_CAN_CMD_SET_BAUD, (void )CAN500kBaud);
/ 以中斷接收及發(fā)送方式打開 CAN 設備 /
res = rt_device_open(can_dev, RT_DEVICE_FLAG_INT_TX | RT_DEVICE_FLAG_INT_RX);
RT_ASSERT(res == RT_EOK);
/ 創(chuàng)建數(shù)據(jù)接收線程 /
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");
}
msg.id = 0x78; / ID 為 0x78 /
msg.ide = RT_CAN_STDID; / 標準格式 /
msg.rtr = RT_CAN_DTR; / 數(shù)據(jù)幀 /
msg.len = 8; / 數(shù)據(jù)長度為 8 /
/ 待發(fā)送的 8 字節(jié)數(shù)據(jù) /
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;
/ 發(fā)送一幀 CAN 數(shù)據(jù) /
size = rt_device_write(can_dev, 0, &msg, sizeof(msg));
if (size == 0)
{
rt_kprintf("can dev write data failed!n");
}
return res;
}
/ 導出到 msh 命令列表中 */
MSH_CMD_EXPORT(can_sample, can device sample);
然后編譯下載到開發(fā)板。

硬件準備
CAN分析儀
CAN——TTL模塊
調試步驟
硬件接好 TTL——CAN TX ————開發(fā)板PB9，TTL——CAN RX————開發(fā)板PB8
通過集線器把CAN分析儀CAN——H 與TTL的CAN——H 相接 CAN——L與CAN——L接好。
通過串品終端執(zhí)行can_sample:

打開CAN分析儀上位機,自動OBD識別，識別到了500K的CAN總，同時也接收到了開發(fā)板發(fā)送的認證數(shù)據(jù)。發(fā)送數(shù)據(jù)，在開發(fā)板的串口終端也成功接收并打印出來：

【總結】

國民技術在RT-Thread上的生態(tài)非常好，可以快速的實現(xiàn)對外設的驅動。