LPC1788 SPI usage

#ifndef __SPI_H_

#define __SPI_H_

#include "common.h"

#include "delay.h"

// cs p1.21

//sck p1.20

//miso p1.23

//mosi p1.24

#define SPI_CLOCK   12000000

void spi0_select_cs(void);

void spi0_disSelect_cs(void);

u8 spi0_rw_data(u8 writeByte);

void spi0_set_speed(u8 speed);

void spi0_init(u8 divide);

#endif

#include "spi.h"

void spi0_select_cs(void)

{

    P1low(21) = 1;

}

void spi0_disSelect_cs(void)

{

    P1high(21) = 1;

}

u8 spi0_rw_data(u8 writeByte)

{

    u8 retry = 200;

    u8 readByte;

    while(!(LPC_SSP0->SR&0x01)) //Wait for sending to complete

    {

        retry--;

        DelayUs(1);

        if(retry == 0)return 1;

    }

    LPC_SSP0->DR = (u16)writeByte;

    retry = 200;

    while(!(LPC_SSP0->SR&0x04))

    {

        retry--;

        DelayUs(1);

        if(retry == 0)return 1;

    }

    readByte = (u8)LPC_SSP0->DR;

    return readByte; 

}

void spi0_set_speed(u8 divide)

{

    LPC_SSP0->CR1 &= ~(1<<1); //stop spi

    LPC_SSP0->CR0 |= ((SPI_CLOCK/(divide-1))<<8);

    LPC_SSP0->CR1 |= (1<<1); //Start spi

}

void spi0_init(u8 divide)

{

    //Turn on the SPI clock and io port clock

    LPC_SC->PCONP |= (1<<15)|(1<<21); //Turn on the clock

    // Placement cs

    LPC_IOCON->P1_21 = 0x00; //Select gpio function, disable hysteresis, non-reverse, normal push-pull

    LPC_IOCON->P1_21 |= (2<<3); //Pull up

    P1dir(21) = 1; // output

    P1high(1) = 1; // high

    LPC_IOCON->P1_20 = 0x00; //Select to disable hysteresis and non-reverse normal push-pull

    LPC_IOCON->P1_20 |= (2<<3)|(5<<0);//上拉 ssp clk

    LPC_IOCON->P1_23 = 0x00; //Select to disable hysteresis and non-reverse normal push-pull

    LPC_IOCON->P1_23 |= (2<<3)|(5<<0); //Pull up ssp miso

    LPC_IOCON->P1_24 = 0x00; //Select to disable hysteresis and non-reverse normal push-pull

    LPC_IOCON->P1_24 |= (2<<3)|(5<<0); //pull up ssp mosi

     //spi interface initialization

    LPC_SSP0->CR0 = 0x0000;

    LPC_SSP0->CR1 = 0x00000000; //Normal operation, host mode

    LPC_SSP0->CR0 |= (7<<0)|(1<<6)|(1<<7)|((SPI_CLOCK/(divide-1))<<8);//8位数据 cpol cpoa

    LPC_SSP0->CPSR = ApbClock/SPI_CLOCK;

    LPC_SSP0->IMSC = 0x00000000; //Disable interrupts

    LPC_SSP0->CR1 |= (1<<1); //Start spi

}