STM32F4入手调试USART,ADC-DMA

在F4-Discovery上调试串口，板上无串口接口芯片，需外接电平转换芯片和串口接口，通过插针引线连接两块电路板，板上3.3V供电180mA不足以支持MAX3232工作，故用usb提供的+5V来为其供电。STM32F405xx/STM32F407xx手册里里写道USART1的Pin map: Tx-PA9;RX-PA10。参考IAP的示例，昨天搞了一晚上无论如何都没有输出，很是奇怪。一直以为初始化不对。今天早晨发现手册Page56中Table7. Alternate function mapping中USART1_TX/USART1_RX映射到PB6/PB7。然后做了如下的初始化，串口的引脚跳到PB6、PB7，果然有输出。那么既然管脚map上首推的映射是PA9/PA10那么为什么没有输出呢，而且用示波器测试一直为高电平？原来Discovery的试验板将PA9连接到usb的vbus供电上了。

如下STM32F4xxxx的USART初始化。

void    USART1_AF_Config(void)

{

  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);

  /* Connect PXx to USARTx_Tx*/

  GPIO_PinAFConfig(GPIOB, GPIO_PinSource6, GPIO_AF_USART1);

  /* Connect PXx to USARTx_Rx*/

  GPIO_PinAFConfig(GPIOB, GPIO_PinSource7, GPIO_AF_USART1);

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;//TX

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;

  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;

  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;

  GPIO_Init(GPIOB, &GPIO_InitStructure);

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;//RX

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;

  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_Init(GPIOB, &GPIO_InitStructure);

    /* USARTx configured as follow:

        - BaudRate = 115200 baud

        - Word Length = 8 Bits

        - One Stop Bit

        - No parity

        - Hardware flow control disabled (RTS and CTS signals)

        - Receive and transmit enabled  */

  USART_InitStructure.USART_BaudRate = 115200;

  USART_InitStructure.USART_WordLength = USART_WordLength_8b;

  USART_InitStructure.USART_StopBits = USART_StopBits_1;

  USART_InitStructure.USART_Parity = USART_Parity_No;

  USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;

  USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;

  USART_Init(USART1, &USART_InitStructure);

  USART_ClockInitStructure.USART_Clock = USART_Clock_Disable;

  USART_ClockInitStructure.USART_CPOL = USART_CPOL_Low;

  USART_ClockInitStructure.USART_CPHA = USART_CPHA_2Edge;

  USART_ClockInitStructure.USART_LastBit = USART_LastBit_Disable;

  USART_Init(USART1, &USART_InitStructure);

  USART_ClockInit(USART1, &USART_ClockInitStructure);

  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);

  NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;

  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;

  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;

  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

  NVIC_Init(&NVIC_InitStructure);

  USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);

  /* Enable USART */

  USART_Cmd(USART1, ENABLE);

  BSP_USART1_Init();

}

 

使用带参数的USART Printf：

#define     BSP_USART1_TX_FIFO_SIZE             1024

#define     BSP_USART1_RX_FIFO_SIZE             128

void BSP_USART1_Init(void)

{

         kfifo_alloc(&usart1_tx_fifo, BSP_USART1_TX_FIFO_SIZE);

         kfifo_alloc(&usart1_rx_fifo, BSP_USART1_RX_FIFO_SIZE);

} 

 

unsigned int BSP_USART1_Write(char* data, unsigned int len)

{

         USART_ITConfig(USART1, USART_IT_TXE, DISABLE);

         len = kfifo_in(&usart1_tx_fifo, (unsigned char*)data, len);

         USART_ITConfig(USART1, USART_IT_TXE, ENABLE);

         return len;

}

 

unsigned int BSP_USART1_Read(char* data, unsigned int len)

{

         len = kfifo_out(&usart1_rx_fifo, (unsigned char*)data, len);

         return len;

}

 

unsigned int BSP_USART1_Printf(char* fmt, ...)

{

         va_list args;

         unsigned int len;

         char *buf = malloc(512);

         va_start(args, fmt);

         vsprintf(buf, fmt, args);

         va_end(args);

         len = BSP_USART1_Write(buf, strlen(buf));

         free(buf);

         return len;

}

 

Stm32f4xx_it.c中isr添加：

#include

#include

#include

 

extern  struct kfifo usart1_tx_fifo;

extern  struct kfifo usart1_rx_fifo;

void  USART1_IRQHandler(void)

{

         uint8_t chr;

         if(USART_GetITStatus(USART1, USART_IT_RXNE))

         {

                   chr = USART_ReceiveData(USART1);

                   kfifo_in(&usart1_rx_fifo, &chr, 1);

         }

         if(USART_GetITStatus(USART1, USART_IT_TXE))

         {

                   USART_ClearITPendingBit(USART1, USART_IT_TXE);

                   if(kfifo_out(&usart1_tx_fifo, &chr, 1))

                            USART_SendData(USART1, chr);

                   else

                            USART_ITConfig(USART1, USART_IT_TXE, DISABLE);

         }

}

主函数调用，在ADC3_DMA示例上进行USART1的添加和使用，需要注意的是用fifo时发送和接收占用了1K多的内存还有USART1_Printf也使用了0.5K的内存，所以需要将heap的容量增大，改到0x800就够。

int main(void)

{  USART1_AF_Config();

  ADC3_CH12_DMA_Config();

  /* Start ADC3 Software Conversion */

  ADC_SoftwareStartConv(ADC3);

  while (1)

  {

  /* convert the ADC value (from 0 to 0xFFF) to a voltage value (from 0V to 3.3V)*/

    ADC3ConvertedVoltage = ADC3ConvertedValue *3300/0xFFF;

    BSP_USART1_Printf("ADCdata: %d\r\n",ADC3ConvertedVoltage);

    Delay(0x3FFFFF);

    BSP_USART1_Printf("%s\r\n",dispstr);

  }

}

STM32F4的DMA channel map也由原来F1的2维DMAx_Channely变成3维DMA_Channelx_DMAy_Streamz，增加了许多。

ADC的DMA全在DMA2上，通道0、1、2上。

  /* DMA2 Stream0 channel0 configuration **************************************/