STM32F4入手调试USART,ADC-DMA

_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 **************************************/

DMA_InitStructure.DMA_Channel = DMA_Channel_2;

DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)ADC3_DR_ADDRESS;

DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)&ADC3ConvertedValue;

DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;

DMA_InitStructure.DMA_BufferSize = 1;

DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;

DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Disable;

DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;

DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;

DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;

DMA_InitStructure.DMA_Priority = DMA_Priority_High;

DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;

DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;

DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;

DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;

DMA_Init(DMA2_Stream0, &DMA_InitStructure);

DMA_Cmd(DMA2_Stream0, ENABLE);