218 lines
5.2 KiB
Markdown
218 lines
5.2 KiB
Markdown
# DAC设备
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[English](dac_EN.md)
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<!-- TOC -->
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* [DAC设备](#dac设备)
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* [打开DAC设备](#打开dac设备)
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* [关闭DAC设备](#关闭dac设备)
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* [控制DAC设备](#控制dac设备)
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* [设置/获取通道编号](#设置获取通道编号)
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* [设置/获取通道配置](#设置获取通道配置)
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* [写入DAC设备通道值](#写入dac设备通道值)
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* [使用示例：](#使用示例)
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<!-- TOC -->
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## 打开DAC设备
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```c
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int mr_dev_open(const char *path, int flags);
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```
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| 参数 | 描述 |
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|---------|---------|
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| path | 设备路径 |
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| flags | 打开设备的标志 |
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| **返回值** | |
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| `>=0` | 设备描述符 |
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| `<0` | 错误码 |
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- `path`：DAC设备路径一般为：`dacx`、`dac1`、`dac2`。
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- `flags`：打开设备的标志，支持 `MR_O_WRONLY`。
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注：使用时应根据实际情况为不同的任务分别打开DAC设备，并使用适当的`flags`进行管理和权限控制，以确保它们不会相互影响。
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## 关闭DAC设备
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```c
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int mr_dev_close(int desc);
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```
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| 参数 | 描述 |
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|---------|-------|
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| desc | 设备描述符 |
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| **返回值** | |
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| `=0` | 关闭成功 |
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| `<0` | 错误码 |
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注：关闭设备时所有的通道都将被自动恢复到默认状态，重新打开后需要重新配置通道（可关闭此功能）。
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## 控制DAC设备
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```c
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int mr_dev_ioctl(int desc, int cmd, void *args);
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```
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| 参数 | 描述 |
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|---------|-------|
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| desc | 设备描述符 |
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| cmd | 命令码 |
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| args | 命令参数 |
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| **返回值** | |
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| `=0` | 设置成功 |
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| `<0` | 错误码 |
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- `cmd`：命令码，支持以下命令：
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- `MR_IOC_DAC_SET_CHANNEL`：设置通道编号。
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- `MR_IOC_DAC_SET_CHANNEL_CONFIG`：设置通道配置。
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- `MR_IOC_DAC_GET_CHANNEL`：获取通道编号。
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- `MR_IOC_DAC_GET_CHANNEL_CONFIG`：获取通道配置。
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### 设置/获取通道编号
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通道编号范围：`0` ~ `31`。
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```c
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/* 定义通道编号 */
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#define CHANNEL_NUMBER 5
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/* 设置通道编号 */
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mr_dev_ioctl(ds, MR_IOC_DAC_SET_CHANNEL, MR_MAKE_LOCAL(int, CHANNEL_NUMBER));
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/* 获取通道编号 */
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int number;
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mr_dev_ioctl(ds, MR_IOC_DAC_GET_CHANNEL, &number);
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```
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不依赖DAC接口：
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```c
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/* 定义通道编号 */
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#define CHANNEL_NUMBER 5
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/* 设置通道编号 */
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mr_dev_ioctl(ds, MR_IOC_SPOS, MR_MAKE_LOCAL(int, CHANNEL_NUMBER));
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/* 获取通道编号 */
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int number;
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mr_dev_ioctl(ds, MR_IOC_GPOS, &number);
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```
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### 设置/获取通道配置
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通道配置：
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- `MR_DISABLE`：禁用通道。
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- `MR_ENABLE`：启用通道。
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```c
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/* 设置通道配置 */
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mr_dev_ioctl(ds, MR_IOC_DAC_SET_CHANNEL_CONFIG, MR_MAKE_LOCAL(int, MR_ENABLE));
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/* 获取通道配置 */
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int state;
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mr_dev_ioctl(ds, MR_IOC_DAC_GET_CHANNEL_CONFIG, &state);
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```
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不依赖DAC接口：
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```c
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/* 设置通道配置 */
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mr_dev_ioctl(ds, MR_IOC_SCFG, MR_MAKE_LOCAL(int, MR_ENABLE));
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/* 获取通道配置 */
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int state;
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mr_dev_ioctl(ds, MR_IOC_GCFG, &state);
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```
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## 写入DAC设备通道值
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```c
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ssize_t mr_dev_write(int desc, const void *buf, size_t count);
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```
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| 参数 | 描述 |
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|---------|---------|
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| desc | 设备描述符 |
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| buf | 写入数据缓冲区 |
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| count | 写入数据大小 |
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| **返回值** | |
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| `>=0` | 写入数据大小 |
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| `<0` | 错误码 |
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```c
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/* 写入通道值 */
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uint32_t data = 2048;
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int ret = mr_dev_write(ds, &data, sizeof(data));
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/* 是否写入成功 */
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if (ret != sizeof(data))
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{
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return ret;
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}
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```
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注：写入数据为DAC原始数据。单次写入最小单位为`uint32_t`，即4个字节。
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## 使用示例：
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```c
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#include "include/mr_lib.h"
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/* 定义通道编号 */
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#define CHANNEL_NUMBER 1
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/* 定义DAC设备描述符 */
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int dac_ds = -1;
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void dac_init(void)
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{
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int ret = MR_EOK;
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/* 初始化DAC */
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dac_ds = mr_dev_open("dac1", MR_O_WRONLY);
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if (dac_ds < 0)
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{
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mr_printf("DAC1 open failed: %s\r\n", mr_strerror(dac_ds));
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return;
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}
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/* 打印DAC描述符 */
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mr_printf("DAC1 desc: %d\r\n", dac_ds);
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/* 设置到通道1 */
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mr_dev_ioctl(dac_ds, MR_IOC_DAC_SET_CHANNEL, MR_MAKE_LOCAL(int, CHANNEL_NUMBER));
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/* 设置通道使能 */
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ret = mr_dev_ioctl(dac_ds, MR_IOC_DAC_SET_CHANNEL_CONFIG, MR_MAKE_LOCAL(int, MR_ENABLE));
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if (ret < 0)
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{
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mr_printf("Channel%d enable failed: %s\r\n", CHANNEL_NUMBER, mr_strerror(ret));
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}
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}
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/* 导出到自动初始化（APP级） */
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MR_INIT_APP_EXPORT(dac_init);
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/* 定义DAC数据最大值 */
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#define DAC_DATA_MAX 4000
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int main(void)
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{
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/* 自动初始化（dac_init函数将在此处自动调用） */
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mr_auto_init();
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while(1)
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{
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uint32_t data = 0;
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for (data = 0; data <= DAC_DATA_MAX; data += 500)
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{
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int ret = mr_dev_write(dac_ds, &data, sizeof(data));
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if (ret != sizeof(data))
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{
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mr_printf("Write failed: %s\r\n", mr_strerror(ret));
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}
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mr_printf("DAC value: %d\r\n", data);
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mr_delay_ms(500);
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}
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}
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}
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```
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DAC1通道1使能，间隔500毫秒输出一次DAC值并打印（输出值递增，步进500，直到达到最大值）。
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