【创龙TMS320C665x开发板试用】基础（十）： spi

ti

由原理图中可知，SPI引脚由J4引出，还有一片Flash。

从芯片手册中，可以查到spi引脚分布如下：

spi的引脚复用不是在GPIO的寄存器中，而是在SPI的SPIPC0寄存器中进行配置。

引脚配置程序，各个宏定义与上面的寄存器是相对应的，不同的是CS引脚的个数，C6655最多只有两个CS引脚。程序中使用的是spiCfg.number_SPI_pins = 4;

spiRegs->SPIPC0 = CSL_SPI_SPIPC0_SOMIFUN_MASK
|CSL_SPI_SPIPC0_SIMOFUN_MASK|CSL_SPI_SPIPC0_CLKFUN_MASK;
if(spiCfg->number_SPI_pins>3)
spiRegs->SPIPC0 |= CSL_SPI_SPIPC0_SCS0FUN0_MASK;
if(spiCfg->number_SPI_pins>4)
spiRegs->SPIPC0 |= CSL_SPI_SPIPC0_SCS0FUN1_MASK;
if(spiCfg->number_SPI_pins>5)
spiRegs->SPIPC0 |= CSL_SPI_SPIPC0_SCS0FUN2_MASK;
if(spiCfg->number_SPI_pins>6)
spiRegs->SPIPC0 |= CSL_SPI_SPIPC0_SCS0FUN3_MASK;

复制代码

然而SPI最终是中实现数据的发送与接收的，这样的一个函数就是KeyStone_SPI_TxRx了。

Uint32 KeyStone_SPI_TxRx(Uint8 * txBuf, Uint32 firstTxByte,
Uint32 numTxByte, Uint8 * rxBuf, Uint32 firstRxByte, Uint32 numRxByte,
SPI_Transfer_Param * transfer)
{
Int32 i;
Int32 length;
Uint32 txData, rxData;
Uint32 byteOfWord, dataFormat, lastDataFormat;
//spiRegs
/*total transfer word length is the max of the lastRxWord and lastTxWord*/
if((firstTxByte+numTxByte)>(firstRxByte+numRxByte))
length= (firstTxByte+numTxByte);
else
length= (firstRxByte+numRxByte);
/*------data format: higher 16 bit of SPIDAT1------*/
KeyStone_SPIDAT1_format(transfer, &dataFormat, &lastDataFormat);
byteOfWord= transfer->byteOfWord;
if(length==byteOfWord)
dataFormat= lastDataFormat;
/*--------write the first word--------*/
if((firstTxByte==0)&&(0
{/*only TX valid data from the "firstTxByte"*/
if(2==byteOfWord)
{/*two bytes*/
txData= *(Uint16 *)txBuf;
txBuf+=2;
}
else
{/*one byte*/
txData= *txBuf++;
}
}
else
txData= 0;
txData |= dataFormat;
/* Wait for room in TX buffer */
if(0==KeyStone_SPI_wait_flag(CSL_SPI_SPIFLG_TXINTFLG_MASK, CSL_SPI_SPIFLG_TXINTFLG_MASK))
return 0;
/* Send the word */
spiRegs->SPIDAT1 = txData;
/*--------write the word n+1 while read word n--------*/
for( i=0; i
{
if((firstTxByte<=i+byteOfWord)&&(i+byteOfWord
{/*only TX valid data from the "firstTxByte"*/
if(2==byteOfWord)
{/*two bytes*/
txData= *(Uint16 *)txBuf;
txBuf+=2;
}
else
{/*one byte*/
txData= *txBuf++;
}
}
else
txData= 0;
if(i+byteOfWord==length-byteOfWord) /*the last word*/
txData |= lastDataFormat;
else
txData |= dataFormat;
/* Wait for room in TX buffer */
if(0==KeyStone_SPI_wait_flag(CSL_SPI_SPIFLG_TXINTFLG_MASK, CSL_SPI_SPIFLG_TXINTFLG_MASK))
return i+byteOfWord;
/* Send the word */
spiRegs->SPIDAT1 = txData;
/* Wait for data in RX buffer */
if(0==KeyStone_SPI_wait_flag(CSL_SPI_SPIFLG_RXINTFLG_MASK, CSL_SPI_SPIFLG_RXINTFLG_MASK))
return i;
/* Read the next word */
rxData = spiRegs->SPIBUF&0xFFFF;
if((firstRxByte<=i)&&(i
{/*only RX valid data from the "firstRxByte"*/
if(2==byteOfWord)
{/*two bytes*/
*(Uint16 *)rxBuf= rxData;
rxBuf+=2;
}
else
{/*one byte*/
*rxBuf++= rxData;
}
}
}
/*--------read the last word--------*/
/* Wait for data in RX buffer */
if(0==KeyStone_SPI_wait_flag(CSL_SPI_SPIFLG_RXINTFLG_MASK, CSL_SPI_SPIFLG_RXINTFLG_MASK))
return length-byteOfWord;
/* Read the next word */
rxData = spiRegs->SPIBUF&0xFFFF;
if((firstRxByte<=length-byteOfWord)&&(length-byteOfWord
{/*only RX valid data from the "firstRxByte"*/
if(2==byteOfWord)
{/*two bytes*/
*(Uint16 *)rxBuf= rxData;
rxBuf+=2;
}
else
{/*one byte*/
*rxBuf++= rxData;
}
}
return length;
}