首先粘貼出官方提供的can例程代碼,根據需要我將部分內容做了修改,供大家參考!
can_sample中包換以下函數: 接收數據回調函數 static rt_err_t can_rx_call(rt_device_t dev, rt_size_t size)
定義can接收線程:static void can_rx_thread(void *parameter)
查找can設備:rt_device_t rt_device_find(const char* name);
打開can設備:rt_err_t rt_device_open(rt_device_t dev, rt_uint16_t oflags);
發生can數據:rt_size_t rt_device_write(rt_device_t dev, rt_off_t pos, const void* buffer, rt_size_t size);
在int can_sample(int argc, char *argv[])中調用can接收線程
其中對于描述是有兩個段代碼可供參考
/*
* 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 can1
* 命令解釋:命令第二個參數是要使用的 CAN 設備名稱,為空則使用默認的 CAN 設備
* 程序功能:通過 CAN 設備發送一幀,并創建一個線程接收數據然后打印輸出。
*/
#include
#include "rtdevice.h"
#define CAN_DEV_NAME "can1" /* 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 */
/* 接收數據回調函數 */
static rt_err_t can_rx_call(rt_device_t dev, rt_size_t size)
{
/* CAN 接收到數據后產生中斷,調用此回調函數,然后發送接收信號量 */
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};
/* 設置接收回調函數 */
rt_device_set_rx_indicate(can_dev, can_rx_call);
while (1)
{
/* hdr 值為 - 1,表示直接從 uselist 鏈表讀取數據 */
rxmsg.hdr = -1;
/* 阻塞等待接收信號量 */
rt_sem_take(&rx_sem, RT_WAITING_FOREVER);
/* 從 CAN 讀取一幀數據 */
rt_device_read(can_dev, 0, &rxmsg, sizeof(rxmsg));
/* 打印數據 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(int argc, char *argv[])
{
struct rt_can_msg msg = {0};
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);
}
/* 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);
/* 以中斷接收及發送方式打開 CAN 設備 */
res = rt_device_open(can_dev, RT_DEVICE_FLAG_INT_TX | RT_DEVICE_FLAG_INT_RX);
RT_ASSERT(res == RT_EOK);
/* 創建數據接收線程 */
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; /* 數據幀 */
msg.len = 8; /* 數據長度為 8 */
/* 待發送的 8 字節數據 */
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;
/* 發送一幀 CAN 數據 */
size = rt_device_write(can_dev, 0, &msg, sizeof(msg));
if (size == 0)
{
rt_kprintf("can dev write data failed!\n");
}
return res;
}
void can_send_test(void)
{
struct rt_can_msg msg = {0};
rt_size_t size;
static rt_uint8_t num = 0;
msg.id = 0x78; /* ID 為 0x78 */
msg.ide = RT_CAN_STDID; /* 標準格式 */
msg.rtr = RT_CAN_DTR; /* 數據幀 */
msg.len = 8; /* 數據長度為 8 */
/* 待發送的 8 字節數據 */
msg.data[0] = 0x00;
msg.data[1] = num++; //can發送數據隨意更改
msg.data[2] = 0x22;
msg.data[3] = 0x33;
msg.data[4] = num++;
msg.data[5] = 0x55;
msg.data[6] = 0x66;
msg.data[7] = 0x77;
/* 發送一幀 CAN 數據 */
size = rt_device_write(can_dev, 0, &msg, sizeof(msg));
if (size == 0)
{
rt_kprintf("can dev write data failed!\n");
}
}
/* 導出到 msh 命令列表中 */
MSH_CMD_EXPORT(can_sample, can device sample);
MSH_CMD_EXPORT(can_send_test, can send test);
另外一個版本,實現的功能是一樣的
/*
* 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 can1
* 命令解釋:命令第二個參數是要使用的 CAN 設備名稱,為空則使用默認的 CAN 設備
* 程序功能:通過 CAN 設備發送一幀,并創建一個線程接收數據然后打印輸出。
*/
#include
#include "rtdevice.h"
#define CAN_DEV_NAME "can1" /* 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 */
#define THREAD_PRIORITY 25
#define THREAD_STACK_SIZE 512
#define THREAD_TIMESLICE 5
static rt_thread_t tid1 = RT_NULL;
/* 接收數據回調函數 */
static rt_err_t can_rx_call(rt_device_t dev, rt_size_t size) {
/* CAN 接收到數據后產生中斷,調用此回調函數,然后發送接收信號量 */
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};
/* 設置接收回調函數 */
rt_device_set_rx_indicate(can_dev, can_rx_call);
while (1) {
/* hdr 值為 - 1,表示直接從 uselist 鏈表讀取數據 */
rxmsg.hdr = -1;
/* 阻塞等待接收信號量 */
rt_sem_take(&rx_sem, RT_WAITING_FOREVER);
/* 從 CAN 讀取一幀數據 */
rt_device_read(can_dev, 0, &rxmsg, sizeof(rxmsg));
/* 打印數據 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");
}
}
/* 線程 1 的入口函數 */
static void thread1_entry(void *parameter) {
struct rt_can_msg msg = {0};
unsigned long count = 0;
msg.id = 0x78; /* ID 為 0x78 */
msg.ide = RT_CAN_STDID; /* 標準格式 */
msg.rtr = RT_CAN_DTR; /* 數據幀 */
msg.len = 8; /* 數據長度為 3 */
/* 待發送的 3 字節數據 */
msg.data[0] = 0x00;
msg.data[1] = 0x11;
msg.data[2] = 0x22;
msg.data[3] = 0x00;
msg.data[4] = 0x11;
msg.data[5] = 0x00;
msg.data[6] = 0x11;
msg.data[7] = 0x22;
rt_kprintf("send %ld \n", ++count);
while (1) {
/* 線程 1 采用低優先級運行,一直打印計數值 */
rt_device_write(can_dev, 0, &msg, sizeof(msg));
rt_kprintf("send %ld \n", ++count);
rt_thread_mdelay(500);
}
}
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);
}
/* 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);
/* 以中斷接收及發送方式打開 CAN 設備 */
res = rt_device_open(can_dev, RT_DEVICE_FLAG_INT_TX | RT_DEVICE_FLAG_INT_RX);
/* 設置 CAN 的工作模式為正常工作模式 */
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_BAUD, (void *)CAN500kBaud);
RT_ASSERT(res == RT_EOK);
/* 創建數據接收線程 */
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");
}
if (size == 0) {
rt_kprintf("can dev write data failed!\n");
}
/* 創建線程 1,名稱是 thread1,入口是 thread1_entry*/
tid1 = rt_thread_create("thread1",
thread1_entry, RT_NULL,
THREAD_STACK_SIZE,
THREAD_PRIORITY, THREAD_TIMESLICE);
/* 如果獲得線程控制塊,啟動這個線程 */
if (tid1 != RT_NULL)
rt_thread_startup(tid1);
else
rt_kprintf("start can send fail\n");
return res;
}
/* 導出到 msh 命令列表中 */
MSH_CMD_EXPORT(can_sample, can device sample);
代碼編譯完成,下載。串口運行:can_sample,打開創芯科技CAN卡,打開電腦的USB CAN工具
![2020-12-08_215917.png](https://club.rt-thread.org/uploads/20201208/4203baee38caefcf1b41511839b7bc93.png)
打開USB轉CAN,選擇對應波特率,這里配置為1Mbps。
重啟,再次運行can_sample,發現,接收到STM32發出的CAN數據幀。
多次運行 can_send_test,電腦端可以接受數據。
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