UART4 UART5

eeeddie

今天调通了USART3，但UART4和UART5调不出来，怀疑是初始化问题？请问问题在那处？

USART3 （正常）:

void USART3_Init(u32 pclk2,u32 bound)
{    
float temp;
u16 mantissa;
u16 fraction;   
temp=(float)(pclk2*1000000)/(bound*16);
mantissa=temp; 
fraction=(temp-mantissa)*16; 
    mantissa<<=4;
mantissa+=fraction; 
RCC->APB2ENR|=1<<3;   
RCC->APB1ENR|=1<<18;  
GPIOB->CRH&=0XFFFF00FF;
GPIOB->CRH|=0X00008B00;
 
RCC->APB1RSTR|=1<<18; 
RCC->APB1RSTR&=~(1<<18);   

USART3->BRR=mantissa;
USART3->CR1|=0X200C; 
#if EN_USART3_RX 
USART3->CR1|=1<<8;   
USART3->CR1|=1<<5;      
MY_NVIC_Init(3,3,USART3_IRQn,2);
#endif
}

UART4（异常）：
void UART4_Init(u32 pclk2,u32 bound)
{    
float temp;
u16 mantissa;
u16 fraction;   
temp=(float)(pclk2*1000000)/(bound*16);
mantissa=temp; 
fraction=(temp-mantissa)*16;   
    mantissa<<=4;
mantissa+=fraction; 
RCC->APB2ENR|=1<<4;   
RCC->APB1ENR|=1<<19;  
GPIOC->CRH&=0XFFFF00FF;
GPIOC->CRH|=0X00008B00;
 
RCC->APB1RSTR|=1<<19; 
RCC->APB1RSTR&=~(1<<19);  

  UART4->BRR=mantissa;
UART4->CR1|=0X200C;  
#if EN_UART4_RX    

UART4->CR1|=1<<8;    
UART4->CR1|=1<<5;    
MY_NVIC_Init(3,3,UART4_IRQn,2);
#endif
}

UART5（异常）：
void UART5_Init(u32 pclk2,u32 bound)
{    
float temp;
u16 mantissa;
u16 fraction;   
temp=(float)(pclk2*1000000)/(bound*16);
mantissa=temp;
fraction=(temp-mantissa)*16;  
mantissa<<=4;
mantissa+=fraction; 
RCC->APB2ENR|=1<<4;  
RCC->APB2ENR|=1<<5;
RCC->APB1ENR|=1<<20; 

GPIOC->CRH&=0XFFF0FFFF;
  GPIOD->CRL&=0XFFFFF0FF;
GPIOC->CRH|=0X000B0000;
GPIOD->CRL|=0X00000800;
 
RCC->APB1RSTR|=1<<20;   
RCC->APB1RSTR&=~(1<<20);     

  UART5->BRR=mantissa;  
UART5->CR1|=0X200C;  
#if EN_UART5_RX

UART5->CR1|=1<<8;    
UART5->CR1|=1<<5;        
MY_NVIC_Init(3,3,UART5_IRQn,2);
#endif
}

eeeddie

发现是卡於这个里 

while((UART4->SR&0X40)==0);

while((UART5->SR&0X40)==0);

eeeddie

我用mini板的，是否芯片不支持?

狼烟四起

STM32F103RB是没有UART4和UART5