全志R128 SDK HAL 模块开发指南之PWM

PWM

模块介绍

脉冲宽度调制（PWM）是一种对模拟信号电平进行数字编码的方法。通过高分辨率计数器的使用，方波的占空比被调制用来对一个具体模拟信号的电平进行编码。PWM 具有以下特点：

支持脉冲（脉冲个数可配）、周期和互补对输出；
支持捕捉输入；
带可编程死区发生器，死区时间可控；
0-24M/100M 输出频率范围、0%-100% 占空比可调、最小分辨率 1/65536；
支持 PWM 输出和捕捉输入产生中断；
支持 PWM 组模式，同组内各个通道起始相位可配置。

模块配置

配置路径如下:

Kernel Setup --->Drivers Setup --->SoC HAL Drivers --->pwm devices --->[*] enable pwm driver

源码结构

rtos-hal/
|--hal/source/pwm/hal_pwm.c    // hal层接口代码
|--include/hal/sunxi_hal_pwm.h // 头文件

模块接口说明

头文件

#include <sunxi_hal_pwm.h>

返回值枚举

typedef enum {HAL_PWM_STATUS_ERROR_PARAMETER = -3,HAL_PWM_STATUS_ERROR_CHANNEL = -2,HAL_PWM_STATUS_ERROR = -1,HAL_PWM_STATUS_OK = 0
} hal_pwm_status_t;

PWM 初始化接口

PWM 模块初始化，主要完成 clk 初始化

函数原型：

pwm_status_t hal_pwm_init(void)

参数：

返回值：

0：成功
负数：失败

PWM 通道配置接口

配置 PWM 模块某个通道，包括周期、占空比和极性

函数原型：

pwm_status_t hal_pwm_control(int channel, struct pwm_config *config_pwm)

参数：

channel 代表通道号
config_pwm 代表该通道的配置参数

返回值：

0：成功
负数：失败

PWM 通道使能接口

使能 PWM 模块某个通道

函数原型：

void hal_pwm_enable_controller(uint32_t channel_in)

参数：

channel_in 代表通道号

返回值：

PWM 去初始化接口

PWM 模块去初始化，主要关闭 clk

函数原型：

pwm_status_t hal_pwm_deinit(void)

参数：

返回值：

0：成功
负数：失败

模块使用范例

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <unistd.h>#include <hal_log.h>
#include <hal_cmd.h>
#include <sunxi_hal_pwm.h>#if defined(CONFIG_ARCH_DSP)
#include <delay.h>
#define sleep(sec) msleep(sec * 1000)
#endif#ifndef printfFromISR
#define printfFromISR printf
#endifstatic int cmd_test_pwm(int argc, char **argv)
{struct pwm_config *config;uint8_t port;//uint8_t ns;int period, duty;if (argc < 4){hal_log_info("Usage: pwm port | duty | period\n");return -1;}hal_log_info("Run pwm hal layer test case\n");port = strtol(argv[1], NULL, 0);hal_log_info("port = %d", port);duty = strtoul(argv[2], NULL, 0);period = strtoul(argv[3], NULL, 0);config = (struct pwm_config *)malloc(sizeof(struct pwm_config));config->duty_ns   = duty;config->period_ns = period;config->polarity  = PWM_POLARITY_NORMAL;hal_log_info("duty_ns = %d \n", config->duty_ns);hal_log_info("period_ns = %d \n", config->period_ns);hal_log_info("polarity = %d \n", config->polarity);hal_pwm_init();hal_pwm_control(port, config);hal_log_info("control pwm test finish\n");return 0;
}FINSH_FUNCTION_EXPORT_CMD(cmd_test_pwm, hal_pwm, pwm hal APIs tests)static int cmd_release_pwm_channel(int argc, char **argv)
{struct pwm_config *config;uint8_t port;uint8_t ns;ulong period, duty;if (argc < 2){hal_log_info("Usage: pwm port\n");return -1;}hal_log_info("Run close pwm channel test case\n");port = strtol(argv[1], NULL, 0);hal_log_info("port = %d", port);hal_pwm_release(port);hal_log_info("release pwm channel finish\n");return 0;
}FINSH_FUNCTION_EXPORT_CMD(cmd_release_pwm_channel, hal_pwm_close, release pwm channel hal APIs tests)static void pwm_cap_callback(void* param)
{hal_pwm_cap_info *info = (hal_pwm_cap_info *)param;printfFromISR("pwm%d capture callback, cnt is %d, period is %d, duty is %d\n", info->channel, info->cnt, info->period, info->duty);
}hal_pwm_status_t pwm_capture_init(uint32_t channel)
{hal_pwm_cap_enable(channel, pwm_cap_callback);return HAL_PWM_STATUS_OK;
}hal_pwm_status_t pwm_capture_deinit(uint32_t channel)
{hal_pwm_cap_disable(channel);return HAL_PWM_STATUS_OK;
}void cmd_pwm_capture_help(void)
{printf("pwm capture test, stop capture after 10s\n");printf("usage: pwm_capture_test<channel>\n");printf("\t<channel>: 0 ~ 15\n");printf("eg: pwm_capture_test 0, pwm0 capture function\n");
}int cmd_pwm_capture(int argc, char *argv[])
{int count = 0;if (argc != 2 || atoi(argv[1]) > 15) {cmd_pwm_capture_help();return -1;}/* capture setting */pwm_capture_init(atoi(argv[1]));for(count = 0; count < 10; count++) {sleep(1);}/* disable */pwm_capture_deinit(atoi(argv[1]));printf("[%s]: pwm stop capture ssd\n", __func__);return 0;
}FINSH_FUNCTION_EXPORT_CMD(cmd_pwm_capture, pwm_capture_test, pwm capture test)