我用LPC2138的SPI控制TRF7960,能寫TRF7960的寄存器(通過寫寄存器,SYS_CLK輸出不同的頻率可以驗證),但讀寄存器總是讀不出來,讀出來都是0,看SPISO的波形也總是低.TRF7960在讀寄存器的時候需要切換CLK的極性.不知道哪位調(diào)試過這個,還請指教哪出了問題.下面是讀寄存器的代碼.
void
SpiReadSingle(u08_t *pbuf, u08_t number)
{? ?
//uint16 i;

SLAVE_SELECT_LOW;? ?? ? // Start SPI Mode

while(number > 0)
{
??*pbuf = (0x40 | *pbuf);? ? // address, read, single
??*pbuf = (0x5f & *pbuf);? ? // register address

? ?SPI_SPDR =*pbuf;
? ?while(!(SPI_SPSR &0x80));
??
??SPI_SPCR = 0x30;//CPOL = 1, CPHA = 0
??
??SPI_SPDR =0;
??while(!(SPI_SPSR &0x80));
??*pbuf = SPI_SPDR;
??pbuf++;
??number--;

??SPI_SPCR = 0x20;//CPOL = 0, CPHA = 0
}

SLAVE_SELECT_HIGH;
}