STM32做双机SPI通信,主机接收数据异常
实验平台:两片STM32F103ZET6实验目的:两片STM32 通过SPI通信的方式,进行发送与接受数据
实验流程:A单片机作为主机,主机设定为按下按键,向从机发送0xAC,并接收从机发来的数据,将其打印在串口屏上;B单片机为从单片机,主机进行发送数据时,从机也同时向主机发送0x69,并接受主机发来的数据,打印在串口屏上。
目前实验现象:从机能够接收到主机发来的数据,能在串口屏上打印0xAC,但主机接收的数据有问题,主机在串口屏上打印的数据时0xAC(应该是0x69) 好复杂,帮顶 主机代码:
//GPIO配置:
void SPI_Master_Init(void)
{
SPI_InitTypeDefSPI_InitStructure;
GPIO_InitTypeDef GPIO_InitStructure;
SPI_APBxClock_FUN ( SPI_CLK, ENABLE );
SPI_CS_APBxClock_FUN ( SPI_CS_CLK|SPI_SCK_CLK|
SPI_MISO_PIN|SPI_MOSI_PIN, ENABLE );
GPIO_InitStructure.GPIO_Pin = SPI_CS_PIN;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode =GPIO_Mode_Out_PP;
GPIO_Init(SPI_CS_PORT, &GPIO_InitStructure);
GPIO_InitStructure.GPIO_Pin = SPI_SCK_PIN;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_Init(SPI_SCK_PORT, &GPIO_InitStructure);
GPIO_InitStructure.GPIO_Pin = SPI_MISO_PIN;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
GPIO_Init(SPI_MISO_PORT, &GPIO_InitStructure);
GPIO_InitStructure.GPIO_Pin = SPI_MOSI_PIN;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_Init(SPI_MOSI_PORT, &GPIO_InitStructure);
SPI_CS_HIGH();
SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
SPI_InitStructure.SPI_Mode = SPI_Mode_Master;
SPI_InitStructure.SPI_DataSize = SPI_DataSize_16b ;
SPI_InitStructure.SPI_CPOL = SPI_CPOL_High;
SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge;
SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_4;
SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
SPI_InitStructure.SPI_CRCPolynomial = 7;
SPI_Init(SPIx , &SPI_InitStructure);
SPI_Cmd(SPIx , ENABLE);
} // 其中 CS PA4、 SCK PA5、MISO PA6、MOSI PA7 主机发送数据函数:
u8 SPI_SendByte(u8 byte)
{
SPITimeout = SPIT_FLAG_TIMEOUT;
while (SPI_I2S_GetFlagStatus(SPIx , SPI_I2S_FLAG_TXE) == RESET)
{
if((SPITimeout--) == 0) return SPI_TIMEOUT_UserCallback(0);
}
SPI_I2S_SendData(SPIx , byte);
SPITimeout = SPIT_FLAG_TIMEOUT;
while (SPI_I2S_GetFlagStatus(SPIx , SPI_I2S_FLAG_RXNE) == RESET)
{
if((SPITimeout--) == 0) return SPI_TIMEOUT_UserCallback(1);
}
return SPI_I2S_ReceiveData(SPIx );
} 同时,该函数也是从机的发送接收数据函数 从机配置:
void SPI_Slave_Init(void)
{
SPI_InitTypeDefSPI_InitStructure;
GPIO_InitTypeDef GPIO_InitStructure;
SPI_APBxClock_FUN ( SPI_CLK, ENABLE );
SPI_CS_APBxClock_FUN ( SPI_CS_CLK|SPI_SCK_CLK|
SPI_MISO_PIN|SPI_MOSI_PIN, ENABLE );
GPIO_InitStructure.GPIO_Pin = SPI_SCK_PIN;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(SPI_SCK_PORT, &GPIO_InitStructure);
GPIO_InitStructure.GPIO_Pin = SPI_MISO_PIN;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_Init(SPI_MISO_PORT, &GPIO_InitStructure);
GPIO_InitStructure.GPIO_Pin = SPI_MOSI_PIN;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU ;
GPIO_Init(SPI_MOSI_PORT, &GPIO_InitStructure);
SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
SPI_InitStructure.SPI_Mode = SPI_Mode_Slave;
SPI_InitStructure.SPI_DataSize = SPI_DataSize_16b ;
SPI_InitStructure.SPI_CPOL = SPI_CPOL_High;
SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge;
SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_4;
SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
SPI_InitStructure.SPI_CRCPolynomial = 7;
SPI_Init(SPIx , &SPI_InitStructure);
SPI_Cmd(SPIx , ENABLE);
}
SPI主从的IO口按照STM32中文手册上进行配置的:
从机采用外部中断接受数据的方式,即主机片选端产生低电平后,从机进入中断,从机的中断配置如下:static void SPI_NVIC_Configuration(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
NVIC_InitStructure.NVIC_IRQChannel = EXTI4_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}
void SPI_EXTI_Config(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
EXTI_InitTypeDef EXTI_InitStructure;
RCC_APB2PeriphClockCmd( RCC_APB2Periph_GPIOA|RCC_APB2Periph_AFIO, ENABLE );
GPIO_InitStructure.GPIO_Pin = SPI_CS_PIN;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
GPIO_Init(SPI_CS_PORT, &GPIO_InitStructure);
//SPI_CS_HIGH();
GPIO_EXTILineConfig(GPIO_PortSourceGPIOA, GPIO_PinSource4);
EXTI_InitStructure.EXTI_Line = EXTI_Line4 ;
EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
EXTI_InitStructure.EXTI_LineCmd = ENABLE;
EXTI_Init(&EXTI_InitStructure); /
SPI_NVIC_Configuration();
}
从机的中断函数:
void EXTI4_IRQHandler(void)
{
if(EXTI_GetITStatus(EXTI_Line4) != RESET)
{
Rec_data=SPI_SendByte(Send_data);
printf("Slave_data=%x Send_data=%x\r\n",Rec_data,Send_data);
}
EXTI_ClearITPendingBit(EXTI_Line4);
}
主机在主程序中的发送函数:int main()
{
unsigned char value=0;
u8 rec=0;
LED_GPIO_Config();
USART1_Config();
Key_GPIO_Config();
SPI_Master_Init();
while(1)
{
value=KEY_Scan();
if(value==2)
{
rec= SPI_send_data(0xAC);
printf("Rec_data=%x\r\n",rec);
}
if(value==3)
{
rec= SPI_send_data(0xBD);
printf("Rec_data=%x\r\n",rec);
}
}
}//其中SPI_send_data函数包括了cs线先拉低,然后发送并接受一个字节,然后CS线拉低
串口屏数据接收情况:主机接受情况
从机接收情况:
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