硬件示意图：

调试方法：

TIM_TimeBaseInitStructure.TIM_Period = 21700;

TIM_OCInitStructure.TIM_Pulse = 21700;

把上面两代码的值设为相等，此时输出的PWM是高电平（即100%占空比），看电流表的值，如果21.715mA。那么，你就改成 TIM_TimeBaseInitStructure.TIM_Period = 21715;

此时你会发现，

执行PWM_SetCompare1(4000); 输出的电流就是4mA；

执行PWM_SetCompare1(20000); 输出的电流就是20mA；

TIM_TimeBaseInitStructure.TIM_Period = 21715; 细调此值，便能输出分辫率为1uA的较精准电流值。

软件代码：

Main函数代码

int main(void)

{

PWM_Init();

while (1)

{

PWM_SetCompare1(4000);

}

}

PWM初始化代码

#include "stm32f10x.h"                  

void PWM_Init(void)

{

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

GPIO_InitTypeDef GPIO_InitStructure;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_Init(GPIOA, &GPIO_InitStructure);

TIM_InternalClockConfig(TIM2);

TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;

TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1;

TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;

TIM_TimeBaseInitStructure.TIM_Period = 21700; //ARR

TIM_TimeBaseInitStructure.TIM_Prescaler = 3; //PSC

TIM_TimeBaseInitStructure.TIM_RepetitionCounter = 0;

TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitStructure);

TIM_OCInitTypeDef TIM_OCInitStructure;

TIM_OCStructInit(&TIM_OCInitStructure);

TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;

TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;

TIM_OCInitStructure.TIM_Pulse = 4000; //CCR

TIM_OC1Init(TIM2, &TIM_OCInitStructure);

TIM_Cmd(TIM2, ENABLE);

}

void PWM_SetCompare1(uint16_t Compare)

{

TIM_SetCompare1(TIM2, Compare);

}