CYPEESS USB3.0程序解读之---SPI读写

前面已经解读了GPIO以及同步FIFO操作，下面我们看一个SPI读写的例子，它是主程序命令从SPI中读写一些数据。

SPI传输子程序看一下： 页地址，字节计数，缓冲区，读写标志

因为只能一页一页的读或写，故读写总是从页地址开始的

/* SPI read / writefor programmer application. */

CyU3PReturnStatus_t

CyFxSpiTransfer (

uint16_t  pageAddress, //页地址

uint16_t  byteCount,      //字节计数

uint8_t *buffer,            //缓冲区

CyBool_t  isRead)                  //读写标志

{

CyU3PDmaBuffer_t buf_p;    //DMA buffer

uint8_t location[4];

uint32_t byteAddress = 0;

uint16_t pageCount = (byteCount /glSpiPageSize);

CyU3PReturnStatus_t status =CY_U3P_SUCCESS;

if (byteCount == 0)

{

return CY_U3P_SUCCESS;

}

if ((byteCount % glSpiPageSize) != 0)

{

pageCount ++;                ///如果除不尽，则按多一页来读写

}

buf_p.buffer = buffer; //地址重载

buf_p.status = 0;

byteAddress = pageAddress * glSpiPageSize;                   //页地址*尺寸=实际地址

CyU3PDebugPrint (2, "SPI access -addr: 0x%x, size: 0x%x, pages: 0x%x.\r\n",

byteAddress, byteCount, pageCount);

while (pageCount != 0)

{

//高字节

location[1] = (byteAddress >> 16)& 0xFF;       /* MS byte */

location[2] = (byteAddress >> 8)& 0xFF;

//低字节

location[3] = byteAddress &0xFF;               /* LS byte */

if (isRead)

{

location[0] = 0x03; /* Read command. *///读命令

buf_p.size  = glSpiPageSize;

buf_p.count = glSpiPageSize;

status = CyFxSpiWaitForStatus ();

if (status != CY_U3P_SUCCESS)

return status;

CyU3PSpiSetSsnLine (CyFalse);

status = CyU3PSpiTransmitWords(location, 4);

if (status != CY_U3P_SUCCESS)

{

CyU3PDebugPrint (2, "SPIREAD command failed\r\n");

CyU3PSpiSetSsnLine (CyTrue);

return status;

}

CyU3PSpiSetBlockXfer (0,glSpiPageSize);        //设置传输尺寸

/// 这个子程序是允许DMA。两个参数一个是TX，一个是RX的个数

status =CyU3PDmaChannelSetupRecvBuffer (&glSpiRxHandle,

&buf_p);

if (status != CY_U3P_SUCCESS)

{

CyU3PSpiSetSsnLine (CyTrue);

return status;

}

status =CyU3PDmaChannelWaitForCompletion (&glSpiRxHandle,

CY_FX_USB_SPI_TIMEOUT);

if (status != CY_U3P_SUCCESS)

{

CyU3PSpiSetSsnLine (CyTrue);

return status;

}

CyU3PSpiSetSsnLine (CyTrue);

CyU3PSpiDisableBlockXfer (CyFalse,CyTrue);

}

else /* Write */

{

location[0] = 0x02; /* Writecommand */

buf_p.size  = glSpiPageSize;

buf_p.count = glSpiPageSize;

status = CyFxSpiWaitForStatus ();

if (status != CY_U3P_SUCCESS)

return status;

CyU3PSpiSetSsnLine (CyFalse);

status = CyU3PSpiTransmitWords(location, 4);

if (status != CY_U3P_SUCCESS)

{

CyU3PDebugPrint (2, "SPIWRITE command failed\r\n");

CyU3PSpiSetSsnLine (CyTrue);

return status;

}

CyU3PSpiSetBlockXfer(glSpiPageSize, 0);

status =CyU3PDmaChannelSetupSendBuffer (&glSpiTxHandle,

&buf_p);

if (status != CY_U3P_SUCCESS)

{

CyU3PSpiSetSsnLine (CyTrue);

return status;

}

status =CyU3PDmaChannelWaitForCompletion(&glSpiTxHandle,

CY_FX_USB_SPI_TIMEOUT);

if (status != CY_U3P_SUCCESS)

{

CyU3PSpiSetSsnLine (CyTrue);

return status;

}

CyU3PSpiSetSsnLine (CyTrue);

CyU3PSpiDisableBlockXfer (CyTrue,CyFalse);

}

/* Update the parameters */

byteAddress  += glSpiPageSize;

buf_p.buffer += glSpiPageSize;

pageCount --;

CyU3PThreadSleep (10);

}

return CY_U3P_SUCCESS;

}

在USB的SETUP中回调中( CyFxUSBSetupCB )，有两个参数，一个是setupdat0,一个是setupdat1.

这两个参数是类，VENDOR调用时的回调函数。

如果是请求ID号，则直接往EP0中写入一个字符串。

如果是请求FLASH写，则从EP0中得到相应的数组。后写到SPI中。

如果是请求读，则从SPI中读出指定长度的数，再送到EP0中去。

如果是请求擦除或点名。则如果点名，就送状态过去，如果是擦除，就送一个ACK包给USB即可。

那么就要了解一下类/VENDOR请求的格式是什么即可。