USART1程序很多，看看USART2程序。注意紅色部分，首先要使能相關端口的時鐘。

因為USART2可以映射成不同的端口，所以要端口映射。

結合你自己的開發板，設置正確的映射口.(正點原子的是PA03PA02.)

STM32F103ZE默認的USART2就是PA03PA02，如果配置映射，USART2端口是PD05PD06了。

程序在正點原子開發板SRAM中調試通過，開發環境IAR5.30.

void USART2_Initialise( u32 bound )

{

GPIO_InitTypeDef GPIO_InitStructure;//I/O?ú3?ê??ˉ?á11ì?

NVIC_InitTypeDef NVIC_InitStructure;//?D??3?ê??ˉ?á11ì?

USART_InitTypeDef USART_InitStructure;//′??ú3?ê??ˉ?á11ì? ?

/* Enable the USART2 Pins Software Remapping */

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA ,?ENABLE);

RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);?

/* Configure USART2 Rx (PA.03) as input floating */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3; ? ?

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;

GPIO_Init(GPIOA, &GPIO_InitStructure);

/* Configure USART2 Tx (PA.02) as alternate function push-pull */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;

GPIO_Init(GPIOA, &GPIO_InitStructure);

/* Enable the USART2 Interrupt */

NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 3;

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

NVIC_Init(&NVIC_InitStructure); ? ?

USART_InitStructure.USART_BaudRate = bound; ? ? ? ? ? ? ? ?//ò?°?éè???a9600;

USART_InitStructure.USART_WordLength = USART_WordLength_8b;//×?3¤?a8??êy?Y??ê?

USART_InitStructure.USART_StopBits = USART_StopBits_1; ? ? //ò???í￡?1??

USART_InitStructure.USART_Parity = USART_Parity_No; ? ? ? ?//?T????D￡?é??

USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//Yá÷????

USART_InitStructure.USART_Mode = USART_Mode_Rx " USART_Mode_Tx;//ê?·￠?￡ê? ??

USART_Init(USART2, &USART_InitStructure);

USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);

//USART_ITConfig(USART2, USART_IT_TXE, ENABLE);

/* Enable USART2 */

USART_Cmd(USART2, ENABLE);

}

void USART2_IRQHandler(void) ?

{ ?

if(USART_GetFlagStatus(USART2, USART_FLAG_RXNE) == SET) ?

{ ? ? ??

USART_SendData(USART2, USART_ReceiveData(USART2)); ? ? ? ? ? ??

}

}

該程序功能是返回你發送到串口的數據。

如果你的USART2接到PD端口上面了，要修改程序如下，這里就需要端口映射了，映射寄存器是AFIO控制的，它接在APB2時鐘區域，所以下面的紅色代碼必須要有，藍色代碼對端口進行初始化。

void USART2_Initialise( u32 bound )

{

GPIO_InitTypeDef GPIO_InitStructure;//I/O?ú3?ê??ˉ?á11ì?

NVIC_InitTypeDef NVIC_InitStructure;//?D??3?ê??ˉ?á11ì?

USART_InitTypeDef USART_InitStructure;//′??ú3?ê??ˉ?á11ì? ?

/* Enable the USART2 Pins Software Remapping */

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOD ,ENABLE);

RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2,ENABLE); ???

RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE);

GPIO_PinRemapConfig(GPIO_Remap_USART2, ENABLE); ???

/* Configure USART2 Rx (PD.06) as input floating */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;?? ?

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;

GPIO_Init(GPIOD, &GPIO_InitStructure);

/* Configure USART2 Tx (PD.05) as alternate function push-pull */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;

GPIO_Init(GPIOD, &GPIO_InitStructure);

/* Enable the USART2 Interrupt */

NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 3;

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

NVIC_Init(&NVIC_InitStructure); ? ?

USART_InitStructure.USART_BaudRate = bound;//ò?°?éè???a9600;

USART_InitStructure.USART_WordLength = USART_WordLength_8b;//×?3¤?a8??êy?Y??ê?

USART_InitStructure.USART_StopBits = USART_StopBits_1;//ò???í￡?1??

USART_InitStructure.USART_Parity = USART_Parity_No;//?T????D￡?é??

USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//?Yá÷????

USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;//ê?·￠?￡ê? ??

USART_Init(USART2, &USART_InitStructure);

USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);

//USART_ITConfig(USART2, USART_IT_TXE, ENABLE);

/* Enable USART2 */

USART_Cmd(USART2, ENABLE);

}

void USART2_IRQHandler(void) ?

{ ?

if(USART_GetFlagStatus(USART2, USART_FLAG_RXNE) == SET) ?

{ ? ? ??

USART_SendData(USART2, USART_ReceiveData(USART2)); ? ? ? ? ? ??

}

}

該程序功能是返回你發送到串口的數據。

如果你的USART2接到PD端口上面了，要修改程序如下，這里就需要端口映射了，映射寄存器是AFIO控制的，它接在APB2時鐘區域，所以下面的紅色代碼必須要有，藍色代碼對端口進行初始化。

void USART2_Initialise( u32 bound )

{

GPIO_InitTypeDef GPIO_InitStructure;//I/O?ú3?ê??ˉ?á11ì?

NVIC_InitTypeDef NVIC_InitStructure;//?D??3?ê??ˉ?á11ì?

USART_InitTypeDef USART_InitStructure;//′??ú3?ê??ˉ?á11ì? ?

/* Enable the USART2 Pins Software Remapping */

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOD ,ENABLE);

RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2,ENABLE); ???

RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE);

GPIO_PinRemapConfig(GPIO_Remap_USART2, ENABLE); ??

/* Configure USART2 Rx (PD.06) as input floating */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;?? ?

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;

GPIO_Init(GPIOD, &GPIO_InitStructure);

/* Configure USART2 Tx (PD.05) as alternate function push-pull */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;

GPIO_Init(GPIOD, &GPIO_InitStructure);

/* Enable the USART2 Interrupt */

NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 3;

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

NVIC_Init(&NVIC_InitStructure); ? ?

USART_InitStructure.USART_BaudRate = bound;//ò?°?éè???a9600;

USART_InitStructure.USART_WordLength = USART_WordLength_8b;//×?3¤?a8??êy?Y??ê?

USART_InitStructure.USART_StopBits = USART_StopBits_1;//ò???í￡?1??

USART_InitStructure.USART_Parity = USART_Parity_No;//?T????D￡?é??

USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//?Yá÷????

USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx; //ê?·￠?￡ê? ??

USART_Init(USART2, &USART_InitStructure);

USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);

//USART_ITConfig(USART2, USART_IT_TXE, ENABLE);

/* Enable USART2 */

USART_Cmd(USART2, ENABLE);

}

void USART2_IRQHandler(void) ?

{ ?

if(USART_GetFlagStatus(USART2, USART_FLAG_RXNE) == SET) ?

{ ? ? ??

USART_SendData(USART2, USART_ReceiveData(USART2)); ? ? ? ? ? ??

}

}