282 lines
6.6 KiB
Markdown
282 lines
6.6 KiB
Markdown
# PWM设备
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[English](pwm_EN.md)
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<!-- TOC -->
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* [PWM设备](#pwm设备)
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* [打开PWM设备](#打开pwm设备)
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* [关闭PWM设备](#关闭pwm设备)
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* [控制PWM设备](#控制pwm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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* [设置/获取频率](#设置获取频率)
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* [读取PWM通道占空比](#读取pwm通道占空比)
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* [写入PWM通道占空比](#写入pwm通道占空比)
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* [使用示例：](#使用示例)
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<!-- TOC -->
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## 打开PWM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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- `name`：PWM设备路径一般为：`pwmx`、`pwm1`、`pwm2`。
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- `flags`：打开设备的标志，支持 `MR_O_RDONLY`、 `MR_O_WRONLY`、 `MR_O_RDWR`。
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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PWM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PWM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配置，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PWM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_PWM_SET_CHANNEL`：设置通道编号。
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- `MR_IOC_PWM_SET_CHANNEL_CONFIG`：设置通道配置。
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- `MR_IOC_PWM_SET_FREQ`：设置频率。
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- `MR_IOC_PWM_GET_CHANNEL`：获取通道编号。
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- `MR_IOC_PWM_GET_CHANNEL_CONFIG`：获取通道配置。
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- `MR_IOC_PWM_GET_FREQ`：获取频率。
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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 1
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/* 设置通道编号 */
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mr_dev_ioctl(ds, MR_IOC_PWM_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_PWM_GET_CHANNEL, &number);
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```
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不依赖PWM接口：
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```c
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/* 定义通道编号 */
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#define CHANNEL_NUMBER 1
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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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struct mr_pwm_config config = {MR_ENABLE, MR_PWM_POLARITY_NORMAL};
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/* 设置通道配置 */
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mr_dev_ioctl(ds, MR_IOC_PWM_SET_CHANNEL_CONFIG, &config);
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/* 获取通道配置 */
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mr_dev_ioctl(ds, MR_IOC_PWM_GET_CHANNEL_CONFIG, &config);
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```
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不依赖PWM接口：
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```c
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int config[] = {MR_ENABLE, 0};
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/* 设置通道配置 */
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mr_dev_ioctl(ds, MR_IOC_SCFG, &config);
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/* 获取通道配置 */
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mr_dev_ioctl(ds, MR_IOC_GCFG, &config);
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```
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### 设置/获取频率
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```c
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/* 定义频率 */
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#define PWM_FREQ 1000
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/* 设置频率 */
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mr_dev_ioctl(ds, MR_IOC_PWM_SET_FREQ, MR_MAKE_LOCAL(uint32_t, PWM_FREQ));
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/* 获取频率 */
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uint32_t freq;
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mr_dev_ioctl(ds, MR_IOC_PWM_GET_FREQ, &freq);
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```
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不依赖PWM接口：
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```c
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/* 定义频率 */
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#define PWM_FREQ 1000
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/* 设置频率 */
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mr_dev_ioctl(ds, (0x01), MR_MAKE_LOCAL(uint32_t, PWM_FREQ));
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/* 获取频率 */
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uint32_t freq;
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mr_dev_ioctl(ds, (-(0x01)), &freq);
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```
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## 读取PWM通道占空比
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```c
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ssize_t mr_dev_read(int desc, 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 | 读取数据缓冲区 |
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| count | 读取数据大小 |
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| **返回值** | |
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| `>=0` | 读取数据大小 |
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| `<0` | 错误码 |
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```c
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/* 读取占空比 */
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uint32_t duty;
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int ret = mr_dev_read(ds, &duty, sizeof(duty));
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/* 是否读取成功 */
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if (ret != sizeof(duty))
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{
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return ret;
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}
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```
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注：读取数据为PWM占空比，范围：`0` ~ `1000000`。单次读取最小单位为`uint32_t`，即4个字节。
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## 写入PWM通道占空比
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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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/* 写入占空比 */
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uint32_t duty = 500000;
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int ret = mr_dev_write(ds, &duty, sizeof(duty));
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/* 是否写入成功 */
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if (ret != sizeof(duty))
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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PWM占空比，范围：`0` ~ `1000000`。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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/* 定义通道编号和频率 */
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#define CHANNEL_NUMBER 1
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#define FREQ 1000
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/* 定义PWM设备描述符 */
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int pwm_ds = -1;
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void pwm_init(void)
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{
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int ret = MR_EOK;
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/* 初始化PWM */
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pwm_ds = mr_dev_open("pwm1", MR_O_RDWR);
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if (pwm_ds < 0)
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{
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mr_printf("PWM1 open failed: %s\r\n", mr_strerror(pwm_ds));
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return;
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}
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/* 打印PWM描述符 */
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mr_printf("PWM1 desc: %d\r\n", pwm_ds);
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/* 设置到通道1 */
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mr_dev_ioctl(pwm_ds, MR_IOC_PWM_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(pwm_ds, MR_IOC_PWM_SET_CHANNEL_CONFIG, MR_MAKE_LOCAL(struct mr_pwm_config, MR_ENABLE, MR_PWM_POLARITY_NORMAL));
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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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return;
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}
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ret = mr_dev_ioctl(pwm_ds, MR_IOC_PWM_SET_FREQ, MR_MAKE_LOCAL(uint32_t, FREQ));
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if (ret < 0)
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{
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mr_printf("Freq configure failed: %s\r\n", 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(pwm_init);
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int main(void)
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{
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/* 自动初始化（pwm_init函数将在此处自动调用） */
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mr_auto_init();
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/* 写入占空比 */
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uint32_t duty = 500000;
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int ret = mr_dev_write(pwm_ds, &duty, sizeof(duty));
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/* 是否写入成功 */
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if (ret != sizeof(duty))
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{
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mr_printf("Write failed: %s\r\n", mr_strerror(ret));
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return ret;
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}
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while(1)
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{
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}
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}
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```
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PWM频率设置为1000Hz，通道1输出50%占空比。
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