STM32 SPI2 读写W25X20的问题

1万 · 2017-11-14 11:24

我用STM32F103C8T6读写W25X20,读出的ID老是0.
原理图：

程序：主函数：
SPI_Flash_Init();
。。。。。。。。。。。。
id=SPI_Flash_ReadID();
flash.c
u16 SPI_FLASH_TYPE=W25X20;

void SPI_Flash_Init(void)
{

GPIO_InitTypeDef GPIO_InitStructure;

  RCC_APB2PeriphClockCmd( RCC_APB2Periph_GPIOB, ENABLE );

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12;  //SPI CS
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;
GPIO_Init(GPIOB, &GPIO_InitStructure);
//GPIO_SetBits(GPIOB,GPIO_Pin_15|GPIO_Pin_13|GPIO_Pin_14);
GPIO_SetBits(GPIOB,GPIO_Pin_12);
SPI2_Init();
SPI2_SetSpeed(SPI_BaudRatePrescaler_4);
SPI_FLASH_TYPE=SPI_Flash_ReadID();
}

SPI.C
SPI_InitTypeDef  SPI_InitStructure;

void SPI2_Init(void)
{
GPIO_InitTypeDef GPIO_InitStructure;

//RCC_APB2PeriphClockCmd( RCC_APB2Periph_GPIOB|RCC_APB1Periph_SPI2, ENABLE );
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);//??GPIOB??
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_SPI2, ENABLE);//??SPI2??

GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_13 | GPIO_Pin_14| GPIO_Pin_15;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB, &GPIO_InitStructure);

GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_12;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB, &GPIO_InitStructure);

//?????SPI????
RCC_APB1PeriphResetCmd(RCC_APB1Periph_SPI2,ENABLE);//??SPI1
RCC_APB1PeriphResetCmd(RCC_APB1Periph_SPI2,DISABLE);//????SPI1

GPIO_SetBits(GPIOB,GPIO_Pin_13|GPIO_Pin_14| GPIO_Pin_15);

SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
SPI_InitStructure.SPI_Mode = SPI_Mode_Master;
SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;
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_2;
SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
SPI_InitStructure.SPI_CRCPolynomial = 7;
SPI_Init(SPI2, &SPI_InitStructure);

SPI_Cmd(SPI2, ENABLE);

SPI2_ReadWriteByte(0xff);
}

u8 SPI2_ReadWriteByte(u8 TxData)
{
u8 retry=0;
while (SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_TXE) == RESET)
{
retry++;
if(retry>200)return 0;
}
SPI_I2S_SendData(SPI2, TxData);
retry=0;

while (SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_RXNE) == RESET)
{
retry++;
if(retry>200)return 0;
}
return SPI_I2S_ReceiveData(SPI2);
}

FLASH.H
#define W25Q80 0XEF13
#define W25Q16 0XEF14
#define W25Q32 0XEF15
#define W25Q64 0XEF16
#define W25X20 0XEF9F

extern u16 SPI_FLASH_TYPE;
#define SPI_FLASH_CS PBout(12)

////////////////////////////////////////////////////////////////////////////

extern u8 SPI_FLASH_BUF[4096];

#define FLASH_ID 0XEF9F

spi.h
请高手看看，哪里有错？谢谢！