//前两个bit 选通道 for(i = 0; i < 2; i ++) //send the channal index { if((channal & 0x02) == 0x02) { P2OUT |= SPI_MOSI; } else { P2OUT &= ~SPI_MOSI; } P2OUT |= SPI_SCK; //Set SPI_SCK to High voltage P2OUT &= ~SPI_SCK; //Set SPI_SCK to low voltage
channal = channal << 1; }
//后八个bit 指定阻值 for(i = 0; i < 8; i ++) //send the resister value { if ((send_data & 0x80) == 0x80) { P2OUT |= SPI_MOSI; } else { P2OUT &= ~SPI_MOSI; } P2OUT |= SPI_SCK; //Set SPI_SCK to High voltage P2OUT &= ~SPI_SCK; //Set SPI_SCK to low voltage