本帖最后由 hehu8 于 2010-4-9 20:26 编辑
LPC2368上有两组SSP0端口，我用P0.15等那一组可以通信。但我用LPC2368的另一组SSP0端口（p1.20等端口），测试SCK0等信号线没有波形。源程序如下：
BYTE SPIbuf[]="1234" ;
int main (void)
{
SPIInit();
while (1)
{
SPISend(SPIbuf,4);
}
return 0;
}
DWORD SPIInit( void )
{
TxCounter = 0;
PCONP |= (1 << 21); /* by default, it's enabled already, for safety reason */
S0SPCR = 0x00;
/* Port 0.15 SPI SCK, port0.16 uses GPIO SPI_SEL,
port0.17 MISO, port0.18 MOSI */
//PINSEL0 |= 0xC0000000;
//PINSEL1 |= 0x0000003C;
//IODIR0 = SPI0_SEL;
//IOSET0 = SPI0_SEL;
PINSEL3 &= 0x0003C300; //对P1.20-P1.28进行端口配置。 0x0003CF00
IODIR1 = SSP0_SEL;
IOSET1 = 0x02000000; //25-ssel 置高
/* Setting SPI0 clock, for Atmel SEEPROM, SPI clock should be no more
than 3Mhz on 4.5V~5.5V, no more than 2.1Mhz on 2.7V~5.5V */
S0SPCCR = 2; //48m/2=24M/12=2Mhz
#if INTERRUPT_MODE
if ( install_irq( SPI0_INT, (void *)SPI0Handler, HIGHEST_PRIORITY ) == FALSE )
{
return (FALSE);
}
/* 8 bit, CPOL=0,CPHA=0, master mode, MSB first, interrupt enabled */
S0SPCR = SPI0_SPIE | SPI0_MSTR ;
#else
S0SPCR = SPI0_MSTR ; //没有允许SPI???
#endif
return( TRUE );
}
void SPISend( BYTE *buf, DWORD Length )
{
DWORD i;
BYTE Dummy;
Dummy = Dummy;
if ( Length == 0 )
return;
for ( i = 0; i < Length; i++ )
{
S0SPDR = *buf;
#if INTERRUPT_MODE
/* In the interrupt, there is nothing to be done if TX_DONE, SPI transfer
complete bit, is not set, so it's polling if the flag is set or not which
is being handled inside the ISR. Not an ideal example but show how the
interrupt is being set and handled. */
while ( (SPI0Status & SPI0_TX_DONE) != SPI0_TX_DONE );
SPI0Status &= ~SPI0_TX_DONE;
#else
while ( !(S0SPSR & SPIF) );
#endif
Dummy = S0SPDR; /* Flush the RxFIFO */
buf++;
}
return;
} |
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