LPC1788的spi使用

#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))//等待发送完成

{

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);//停止spi

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

LPC_SSP0->CR1 |= (1<<1);//启动spi

}

void spi0_init(u8 divide)

{

//打开SPI时钟和io口时钟

LPC_SC->PCONP |= (1<<15)|(1<<21);//打开时钟

//配置cs

LPC_IOCON->P1_21 = 0x00;//选择gpio功能,禁止迟滞 不反向 正常推挽

LPC_IOCON->P1_21 |= (2<<3);//上拉

P1dir(21) = 1;//输出

P1high(1) = 1;//为高

LPC_IOCON->P1_20 = 0x00;//选择禁止迟滞 不反向 正常推挽

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

LPC_IOCON->P1_23 = 0x00;//选择禁止迟滞 不反向 正常推挽

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

LPC_IOCON->P1_24 = 0x00;//选择禁止迟滞 不反向 正常推挽

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

//spi接口初始化

LPC_SSP0->CR0 = 0x0000;

LPC_SSP0->CR1  = 0x00000000;//正常操作,主机模式

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;//禁止中断

LPC_SSP0->CR1 |= (1<<1);//启动spi

}