3. MCPWM

Overview

以 AC635N 为例，输出可配比的 PWM，可用于电机控制，也可以做普通 PWM。提供 MCPWM 的应用示例、工程配置、API 介绍和常见问题。

3.1. 应用示例

MCPWM 的具体源代码详见 sdk/bsp/AC635N/src/mcpwm.c

mcpwm.c 中参考示例如下:

/**********mcpwm参考示例**********/
void mcpwm_test(void)
{
#define PWM_CH3_ENABLE          1
#define PWM_CH4_ENABLE          1
#define PWM_CH5_ENABLE          1
#define PWM_CH0_ENABLE          1
#define PWM_CH1_ENABLE          1
#define PWM_CH2_ENABLE          1

    struct pwm_platform_data pwm_p_data;

#if PWM_CH3_ENABLE
    memset((u8 *)&pwm_p_data, 0, sizeof(struct pwm_platform_data));
    pwm_p_data.pwm_ch_num = pwm_ch3;                        //通道0
    pwm_p_data.frequency = 1000;                                //1KHz
    pwm_p_data.duty = 5000;                                 //占空比50%
    pwm_p_data.h_pin = -1;                                              //不用则填 -1
    pwm_p_data.l_pin = IO_PORTB_10;                         //硬件引脚
    mcpwm_init(&pwm_p_data);
#endif

#if PWM_CH4_ENABLE
    memset((u8 *)&pwm_p_data, 0, sizeof(struct pwm_platform_data));
    pwm_p_data.pwm_ch_num = pwm_ch4;                        //通道0
    pwm_p_data.frequency = 10000;                               //10KHz
    pwm_p_data.duty = 5000;                                 //占空比50%
    pwm_p_data.h_pin = IO_PORTA_09;                         //硬件引脚
    pwm_p_data.l_pin = IO_PORTA_10;                         //硬件引脚
    pwm_p_data.complementary_en = 1;                        //两个引脚的波形, 1: 互补, 0: 同步;
    mcpwm_init(&pwm_p_data);
#endif

#if PWM_CH5_ENABLE
    memset((u8 *)&pwm_p_data, 0, sizeof(struct pwm_platform_data));
    pwm_p_data.pwm_ch_num = pwm_ch5;                        //通道0
    pwm_p_data.frequency = 2000;                                //2KHz
    pwm_p_data.duty = 5000;                                 //占空比50%
    pwm_p_data.h_pin = IO_PORTC_04;                         //硬件引脚
    pwm_p_data.l_pin = -1;                                              //不用则填 -1

    mcpwm_init(&pwm_p_data);
#endif

#if PWM_CH0_ENABLE
    memset((u8 *)&pwm_p_data, 0, sizeof(struct pwm_platform_data));
    pwm_p_data.pwm_ch_num = pwm_ch0;                        //通道0
    pwm_p_data.frequency = 1000;                                //1KHz
    pwm_p_data.duty = 5000;                                 //占空比50%
    pwm_p_data.h_pin = IO_PORTA_03;                         //非硬件引脚，即任意IO
    pwm_p_data.h_pin_output_ch_num = 1;                                         //当h_pin为非硬件IO时，分频outputchannel号: 0/1/2
    pwm_p_data.l_pin = -1;                                              //不用则填 -1
    mcpwm_init(&pwm_p_data);
#endif

#if PWM_CH1_ENABLE
    memset((u8 *)&pwm_p_data, 0, sizeof(struct pwm_platform_data));
    pwm_p_data.pwm_ch_num = pwm_ch1;                        //通道0
    pwm_p_data.frequency = 10000;                               //10KHz
    pwm_p_data.duty = 5000;                                 //占空比50%
    pwm_p_data.h_pin = IO_PORTB_00;                         //硬件引脚
    pwm_p_data.l_pin = IO_PORTB_03;                         //非硬件引脚，即任意IO
    pwm_p_data.l_pin_output_ch_num = 2;                                         //当l_pin为非硬件IO时，分频outputchannel号: 0/1/2
    pwm_p_data.complementary_en = 1;                        //两个引脚的波形, 1: 互补, 0: 同步;
    mcpwm_init(&pwm_p_data);
#endif

#if PWM_CH2_ENABLE
    memset((u8 *)&pwm_p_data, 0, sizeof(struct pwm_platform_data));
    pwm_p_data.pwm_ch_num = pwm_ch2;                        //通道0
    pwm_p_data.frequency = 2000;                                //2KHz
    pwm_p_data.duty = 5000;                                 //占空比50%
    pwm_p_data.h_pin = IO_PORTB_04;                         //硬件引脚
    pwm_p_data.l_pin = -1;                                              //不用则填 -1

    mcpwm_init(&pwm_p_data);
#endif

#if 0
    extern void wdt_clear();
    while (1) {
        wdt_clear();
    }
#endif
}

3.2. 工程配置

在 sdk/apps/main.c 中函数 user_main() 添加如下工程代码:

int user_main()
{
    extern void mcpwm_test(void);
    mcpwm_test();
}

编译下载后，用示波器连接测试IO，观察是否符合如下期望输出：

PB10

1KHz50%

PA9&PA10

10KHz%50互补

PC4

2KHz50%

PA3

1KHz50%

PB0&PB3

10KHz%50互补

PB4

2KHz50%

3.3. API参考

MCPWM 常用相关 API 介绍，具体软件代码见 sdk/bsp/AC635N/src/mcpwm.c

Functions

void mcpwm_set_frequency(pwm_ch_num_type ch, u32 frequency)

更改MCPWM的频率

Parameters

ch – 通道号
frequency – 频率

void mcpwm_set_duty(pwm_ch_num_type pwm_ch, u16 duty)

设置一个通道的占空比

Parameters

pwm_ch – 通道号：pwm_ch0，pwm_ch1，pwm_ch2
duty – 占空比：0 ~ 10000 对应 0% ~ 100%

void mctimer_ch_open_or_close(pwm_ch_num_type pwm_ch, u8 enable)

打开或者关闭一个时基

Parameters

pwm_ch – 通道号：pwm_ch0，pwm_ch1，pwm_ch2
enable – 1：打开 0：关闭

void mcpwm_ch_open_or_close(pwm_ch_num_type pwm_ch, u8 enable)

打开或者关闭一个通道

Parameters

pwm_ch – 通道号：pwm_ch0，pwm_ch1，pwm_ch2
enable – 1：打开 0：关闭

void mcpwm_open(pwm_ch_num_type pwm_ch)

关闭MCPWM模块

Parameters: pwm_ch – 通道号：pwm_ch0，pwm_ch1，pwm_ch2

void mcpwm_close(pwm_ch_num_type pwm_ch)

关闭MCPWM模块

Parameters: pwm_ch – 通道号：pwm_ch0，pwm_ch1，pwm_ch2

void mcpwm_init(struct pwm_platform_data *arg)

pwm初始化函数

Parameters: arg – 初始化的参数结构体地址： struct pwm_platform_data *

void mcpwm_test(void): pwm参考示例函数

PB10	1KHz50%
PA9&PA10	10KHz%50互补
PC4	2KHz50%
PA3	1KHz50%
PB0&PB3	10KHz%50互补
PB4	2KHz50%