TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;
TIM_OCInitStructure.TIM_Pulse = Pluse;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_High;
TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set;
TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCNIdleState_Set;

TIM_OC1Init(BLDC_TIMER_NUM, &TIM_OCInitStructure);

TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2;
Pluse = MotorA.TimerPeriod - Pluse;
TIM_OCInitStructure.TIM_Pulse = Pluse;
TIM_OC2Init(BLDC_TIMER_NUM, &TIM_OCInitStructure);

#define Fsys 72000000ul // system freq 72MHz
#define Fpwm 20000 // PWM freq 20K

void ConfigTimer(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
GPIO_InitTypeDef GPIO_InitStructure;

RCC_APB1PeriphClockCmd( RCC_APB1Periph_TIM4,ENABLE);
RCC_APB2PeriphClockCmd( RCC_APB2Periph_GPIOB,ENABLE);

TIM_DeInit(TIM4);
TIM_TimeBaseStructure.TIM_Prescaler = 0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_CenterAligned1;
TIM_TimeBaseStructure.TIM_Period = (Fsys/2) / Fpwm;
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseStructure.TIM_RepetitionCounter = 0;
TIM_TimeBaseInit(TIM4,&TIM_TimeBaseStructure);

TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_OutputNState = TIM_OutputState_Disable;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_Low;
TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Reset;
TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCIdleState_Reset;
TIM_OCInitStructure.TIM_Pulse = (((Fsys/2) / Fpwm) * 20) / 100;
TIM_OC3Init(TIM4,&TIM_OCInitStructure);

TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2;
TIM_OCInitStructure.TIM_Pulse = (((Fsys/2) / Fpwm) * (100-20)) / 100;
TIM_OC4Init(TIM4,&TIM_OCInitStructure);

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_9;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB, &GPIO_InitStructure);

TIM_CtrlPWMOutputs(TIM4, ENABLE);
TIM_Cmd(TIM4,ENABLE);
}

基本設(shè)置如下：
1）配置定時(shí)器的計(jì)數(shù)器為中間對齊計(jì)數(shù)，即先向上計(jì)數(shù)再向下計(jì)數(shù)。
2）在該定時(shí)器上選擇2個(gè)通道，并分別配置為輸出比較模式，并配置在比較成功時(shí)翻轉(zhuǎn)對應(yīng)的引腳輸出。
3）配置自動重裝載寄存器TIMx_ARR為要求輸出頻率的一半。
4）假定CC1為第一個(gè)輸出信號的通道，再假定第一個(gè)信號的正脈沖寬度對應(yīng)為W1，則配置TIMx_CCR1為TIMx_ARR-W1/2。
5) 同4），假定CC2為第二個(gè)輸出信號的通道，正脈沖寬度對應(yīng)為W2，配置TIMx_CCR2為W2/2。

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下面以一個(gè)例子說明：

假設(shè)要求輸出的信號頻率為10kHz，占空比為1:3。
再假設(shè)定時(shí)器的輸入時(shí)鐘為72MHz。

輸出信號的頻率10kHz，換算為計(jì)數(shù)器的數(shù)值為7200。
按照上述3），設(shè)置TIMx_ARR=3600

輸出信號1的高電平時(shí)間W1，換算為計(jì)數(shù)器的數(shù)值為W1=7200/4=1800
按照上述4），設(shè)置TIMx_CC1=3600 - W1/2=2700

輸出信號2的高電平時(shí)間W2，換算為計(jì)數(shù)器的數(shù)值為W2=7200/4=1800
按照上述5），設(shè)置TIMx_CC2=2/2=450

參照下圖，圖中紅線表示計(jì)數(shù)器的數(shù)值變化：
①當(dāng)計(jì)數(shù)器的數(shù)值從0向上計(jì)數(shù)，達(dá)到TIMx_CC1時(shí)，CC1匹配成功，CC1的輸出電平翻轉(zhuǎn)；
②計(jì)數(shù)器繼續(xù)向上計(jì)數(shù)，達(dá)到TIMx_ARR時(shí)開始調(diào)頭向下計(jì)數(shù)；當(dāng)計(jì)數(shù)器的數(shù)值下降到TIMx_CC1時(shí)，CC1再次匹配成功，CC1的輸出電平再次翻轉(zhuǎn)；
③計(jì)數(shù)器繼續(xù)向下計(jì)數(shù)，達(dá)到到TIMx_CC2時(shí)，CC2匹配成功，CC2的輸出電平翻轉(zhuǎn)；
④計(jì)數(shù)器繼續(xù)向下計(jì)數(shù)，減到0時(shí)開始調(diào)頭向上計(jì)數(shù)；當(dāng)計(jì)數(shù)器的數(shù)值上升到TIMx_CC2時(shí)，CC2再次匹配成功，CC2的輸出電平再次翻轉(zhuǎn)；

如此循環(huán)，得到連續(xù)的相位互為180度的兩路輸出波形。

注意：上述描述是一個(gè)原理性的說明，但能夠輸出要求的波形并且占空比可調(diào)，實(shí)際編程計(jì)算中需要可能需要對某些數(shù)值加1或者減1，以達(dá)到準(zhǔn)確地輸出。