帮我用C写一段CANopen SDO收发函数
时间: 2023-12-14 22:37:49 浏览: 110
CANopen SDO(Service Data Object)是一种用于在CAN总线上进行数据传输的协议。下面是一个简单的CANopen SDO收发函数的示例,使用C语言编写:
```c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "canopen.h"
#define CANOPEN_COBID_SDO_TX 0x600
#define CANOPEN_COBID_SDO_RX 0x580
typedef struct {
uint16_t index;
uint8_t subindex;
uint8_t data[4];
} canopen_sdo_t;
int canopen_sdo_write(canopen_sdo_t *sdo) {
uint8_t tx_buf[8];
uint8_t rx_buf[8];
int ret;
tx_buf[0] = 0x23;
tx_buf[1] = sdo->index & 0xFF;
tx_buf[2] = (sdo->index >> 8) & 0xFF;
tx_buf[3] = sdo->subindex;
memcpy(&tx_buf[4], sdo->data, 4);
ret = can_send(CANOPEN_COBID_SDO_TX, tx_buf, 8);
if (ret < 0) {
return ret;
}
ret = can_recv(CANOPEN_COBID_SDO_RX, rx_buf, 8, 1000);
if (ret < 0) {
return ret;
}
if (rx_buf[0] != 0x60) {
return -1;
}
return 0;
}
int canopen_sdo_read(canopen_sdo_t *sdo) {
uint8_t tx_buf[8];
uint8_t rx_buf[8];
int ret;
tx_buf[0] = 0x40;
tx_buf[1] = sdo->index & 0xFF;
tx_buf[2] = (sdo->index >> 8) & 0xFF;
tx_buf[3] = sdo->subindex;
memset(&tx_buf[4], 0, 4);
ret = can_send(CANOPEN_COBID_SDO_TX, tx_buf, 8);
if (ret < 0) {
return ret;
}
ret = can_recv(CANOPEN_COBID_SDO_RX, rx_buf, 8, 1000);
if (ret < 0) {
return ret;
}
if (rx_buf[0] != 0x43) {
return -1;
}
memcpy(sdo->data, &rx_buf[4], 4);
return 0;
}
```
这个函数包含两个函数:
- `canopen_sdo_write`:用于将数据写入CANopen SDO对象。
- `canopen_sdo_read`:用于从CANopen SDO对象读取数据。
这个函数假定CAN总线的接口已经设置好了,其中`can_send`和`can_recv`函数用于实现CAN数据发送和接收。
使用这个函数的示例代码如下:
```c
#include <stdio.h>
#include "canopen.h"
int main() {
canopen_sdo_t sdo;
int ret;
// 写入数据
sdo.index = 0x1017;
sdo.subindex = 0x00;
sdo.data[0] = 0x01;
sdo.data[1] = 0x00;
sdo.data[2] = 0x00;
sdo.data[3] = 0x00;
ret = canopen_sdo_write(&sdo);
if (ret < 0) {
printf("Error writing SDO: %d\n", ret);
return -1;
}
// 读取数据
sdo.index = 0x1018;
sdo.subindex = 0x01;
memset(sdo.data, 0, 4);
ret = canopen_sdo_read(&sdo);
if (ret < 0) {
printf("Error reading SDO: %d\n", ret);
return -1;
}
printf("SDO data: %02x %02x %02x %02x\n", sdo.data[0], sdo.data[1], sdo.data[2], sdo.data[3]);
return 0;
}
```
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