有哪位高手用STM32F303XB JTAG JTDO口（B3）做TIM8输出

qingzhu-325396 提问时间：2017-2-17 10:24 /

将STM32F303CBT6的39脚（B3）复用为TIM8_CH1N，做PWM三相互补输出，发现除TIM8_CH1N外，其他输出均正常，有哪位高手可以指点一下。
/* GPIOB&TIM8 Periph clock enable */
RCC->APB2ENR |= 0x00002000;
RCC->AHBENR |= 0x00040000;

//IO
GPIOB->AFR[0] &= 0x00000FFF;
GPIOB->AFR[0] |= 0x55344000;
GPIOB->AFR[1] &= 0xFFFFFF00;
GPIOB->AFR[1] |= 0x000000AA;

/* Speed mode configuration */
GPIOB->OSPEEDR |= 0x000FFFC0;
/* Output mode configuration */
GPIOB->OTYPER &= 0xFFFFFC07;

GPIOB->

UPDR &= 0xFFF0003F;
GPIOB->

UPDR |= 0x000AAA80;

GPIOB->MODER &= 0xFFF0003F;
GPIOB->MODER |= 0x000A2A80;

/****TimeBaseInit********/
//tDTS=tCK_INT, TIM8_ARR register is not buffered;Center-aligned mode 3
TIM8->CR1 = 0x00E0;

//25uS*2;20KHz(1800)
//25uS;40KHz()
/* Set the Autoreload value */
TIM8->ARR = 1800 ;

/* Set the Prescaler value */
TIM8->

SC = 0;

/* Generate an update event to reload the Prescaler
and the repetition counter(only for TIM1 and TIM8) value immediatly */
TIM8->EGR = 0x0001;

/* Reset the Output Polarity level */
TIM8->CCER = 0x00000000;

/* Write to TIMx CR2 */
TIM8->CR2 = 0;

/* Reset the Output Compare Mode Bits */
//PWMA,B,C,4

WM mode2
TIM8->CCMR1 = 0x00007070;
TIM8->CCMR2 = 0x00007070;
//PWM5
TIM8->CCMR3 = 0x00000060;

/* Set the Capture Compare Register value */
TIM8->CCR1 = 600;
TIM8->CCR2 = 900;
TIM8->CCR3 = 1500;
TIM8->CCR4 = 1800;
TIM8->CCR5 = 1740;

/* Set the Output Compare Polarity */
TIM8->CCER |= 0x00011555;

/* Reset the Output Compare Mode Bits */
//TIM8->CCMR1 &= 0xFFFFF7F7;
//TIM8->CCMR2 &= 0xFFFFF7F7;
//TIM8->CCMR3 &= 0xFFFFFFF7;

TIM8->BDTR = 0x00028108;//????

TIM8->SR &=0xFF7E;
TIM8->DIER = 0x0000;

/* Enable the TIM Counter */
TIM8->CR1 &= 0xFFFE;
TIM8->CR1 |= 0x0001;