关于使用SPI调试SPI FLASH的问题

只看该作者 · 2014-8-21 10:14

小弟我用STM8的SPI功能,调试MX25L6406E这个64MB的SPI_Flash(硬件是搭了一个万用表然后飞线到学习板的SPI口上面的).使用的是SPI的模式3方式进行数据的传送接收.时钟使用Fcpu / 2.
主要涉及的代码如下:

/*
* Function:    Wait_Flash_WarmUp
* Arguments:    None.
* Description: Wait some time until flash read / write enable.
* Return Message: None.
*/
void Wait_Flash_WarmUp()
{
uint32 time_cnt = FlashFullAccessTime;
while( time_cnt > 0 )
{
      time_cnt--;
}
}

/*
* Function:    Initial_Spi
* Arguments:    None
* Description: Initial spi flash state and wait flash warm-up
*                (enable read/write).
* Return Message: None
*/
void Initial_Spi()
{
GPIO_Init(CS_PIN,GPIO_MODE_OUT_PP_HIGH_FAST);
GPIO_Init(SPI_SCK_PIN,GPIO_MODE_OUT_PP_HIGH_FAST);
GPIO_Init(SPI_MOSI_PIN,GPIO_MODE_OUT_PP_HIGH_FAST);
GPIO_Init(SPI_MISO_PIN,GPIO_MODE_IN_PU_NO_IT);

SPI_DeInit();
SPI_Init(SPI_FIRSTBIT_MSB,SPI_BAUDRATEPRESCALER_16,SPI_MODE_MASTER,SPI_CLOCKPOLARITY_HIGH,\
SPI_CLOCKPHASE_2EDGE,SPI_DATADIRECTION_2LINES_FULLDUPLEX,SPI_NSS_SOFT,0x07);
SPI_Cmd(TRUE);

// Wait flash warm-up
Wait_Flash_WarmUp();
}

/*
* Function:    CS_Low, CS_High
* Arguments:    None.
* Description: Chip select go low / high.
* Return Message: None.
*/
void CS_Low()
{
GPIO_WriteLow(CS_PIN);
}

void CS_High()
{
//--- insert your chip select code here. ---//
GPIO_WriteHigh(CS_PIN);
}

/*
* Function:    SendByte
* Arguments:    byte_value, data transfer to flash
*                transfer_type, select different type of I/O mode.
*                Seven mode:
*                SIO, single IO
*                DIO, dual IO
*                QIO, quad IO
*                PIO, parallel
*                DTSIO, double transfer rate SIO
*                DTDIO, double transfer rate DIO
*                DTQIO, double transfer rate QIO
* Description: Send one byte data to flash
* Return Message: None.
*/
void SendByte( uint8 byte_value, uint8 transfer_type )
{
while(SPI_GetFlagStatus(SPI_FLAG_TXE) == RESET);

SPI_SendData(byte_value);

}
/*
* Function:    GetByte
* Arguments:    byte_value, data receive from flash
*                transfer_type, select different type of I/O mode.
*                Seven mode:
*                SIO, single IO
*                DIO, dual IO
*                QIO, quad IO
*                PIO, parallel IO
*                DTSIO, double transfer rate SIO
*                DTDIO, double transfer rate DIO
*                DTQIO, double transfer rate QIO
* Description: Get one byte data to flash
* Return Message: 8 bit data
*/
uint8 GetByte( uint8 transfer_type )
{
uint8 data_buf;
SendByte( DUMMY_BYTE, SIO );
while(SPI_GetFlagStatus(SPI_FLAG_RXNE) == RESET);
data_buf = SPI_ReceiveData();

return data_buf;
}

///////////////以下是测试代码//////////////////////////////
#define  TRANS_LENGTH  16
#define  RANDOM_SEED 106
#define  FLASH_TARGET_ADDR  0x00000000

#define  Error_inc(x)  x = x + 1;
/*
* Simple flash ID test
*/
uint8 FlashID_Test( void )
{
uint32  flash_id = 0;
uint16  error_cnt = 0;
uint16  rems_id;
uint8 electric_id = 0;
FlashStatus  flash_state = {0};
ReturnMsg  msg;

/* Read flash device id */
msg =  CMD_RDID( &flash_id );
if( msg != (ReturnMsg)FlashOperationSuccess )
      return FALSE;

msg = CMD_RES( &electric_id );
if( msg != (ReturnMsg)FlashOperationSuccess )
      return FALSE;

/* Decide rems_id order. 0: { manufacturer id, device id }
                           1: { device id,  manufacturer id } */
flash_state.ArrangeOpt = 0;

msg = CMD_REMS( &rems_id, &flash_state );
if( msg != (ReturnMsg)FlashOperationSuccess )
      return FALSE;

/* Compare to expected value */
if( flash_id != FlashID )
      Error_inc( error_cnt );

if( electric_id != ElectronicID )
      Error_inc( error_cnt );

if( flash_state.ArrangeOpt )
{
      if( rems_id != RESID1 )
         Error_inc( error_cnt );
}else
{
      if( rems_id != RESID0 )
         Error_inc( error_cnt );
}

if( error_cnt != 0 )
      return FALSE;
else
      return TRUE;
}

//////
发现测试代码读取回来的值并非datasheet说的值.datasheet的值如下:
#define FlashID       0xc22017
#define ElectronicID    0x16
#define RESID0          0xc216
#define RESID1          0x16c2

因此,小弟想请教一下,SPI这个读数据会不会跟硬件是飞线的原因造成的.另外MISO及MOSI这个两个口都没有接外部上拉电阻.
还是我上面软件配置哪里有异常?
请大家指教,谢谢