LPC2478的spi使用

LPC2748具有一个SPI控制器,可以当做SPI主机或者从机使用,有以下特性

其使用起来很方便,并且支持中断,使用的寄存器如下

基本上,使用起来就是设置控制为,CPOL CPOA等等,数据长度的配置等,设置分频率,发送数据,等待状态或者中断,发送完成,就OK了

官方给出的流程如下

操作过程见以下代码

#ifndef __SPI0_H_

#define __SPO0_H_

#include "common.h"

#include "lpc24xx.h"

#include "clock.h"

typedef enum SPI0_SPEED

{

    SPI_SPEED1 = 100000,

    SPI_SPEED2 = 500000,

    SPI_SPEED3 = 1000000,

    SPI_SPEED4 = 1500000,

    SPI_SPEED5 = 2000000,

    SPI_SPEED6 = 3125000

}SPI0_SPEED;

typedef enum SPI_BITFRIST

{

    msbFrist = 0,

    lsbFrist = 1

}SPI_BITFRIST;

void Spi0SelectCs(void);

void Spi0DisSelectCs(void);

u8 Spi0RwData(u8 writeByte,u8* readByte);

void Spi0SetSpeed(SPI0_SPEED speed);

void Spi0Init(SPI0_SPEED speed,SPI_BITFRIST bitFrist);

#endif

#include "spi.h"

#define BIT_ENABLE_POSITION     2

#define CPHA_POSITION           3

#define CPOL_POSITION           4

#define MSTR_POSITION           5

#define LSBF_POSITION           6

#define SPIE_POSITION           7

#define BITS_POSITION           8

void Spi0Init(SPI0_SPEED speed,SPI_BITFRIST bitFrist)

{

    u32 spiClock = (SystemCoreClock/4)/speed;

    PCONP |= (1 << 8);//打开SPI时钟

	SCS |= (1<<0);//设置高速寄存器组方式访问端口

    //sck

    PINSEL0 &= ~(0x03u<<30);

    PINSEL0 |= (0x03u<<30);

    PINMODE0 &= ~(0x03u<<30);

    //csn 普通GPIO 不用硬件CSN

    PINSEL1 &= ~(0x03<<0);

    PINMODE1 &= ~(0x03<<0);

    FIO0DIR |= (1<<16);

    //miso

    PINSEL0 &= ~(0x03<<2);

    PINSEL0 |= (0x03<<2);

    PINMODE0 &= ~(0x03<<2);

    //mosi

    PINSEL0 &= ~(0x03<<4);

    PINSEL0 |= (0x03<<4);

    PINMODE0 &= ~(0x03<<4);

    //spi接口初始化

    S0SPCR = (0<<BIT_ENABLE_POSITION)|(1<<CPHA_POSITION)|(1<<CPOL_POSITION)|(1<<MSTR_POSITION)|(bitFrist<<LSBF_POSITION)\

                    |(0<<SPIE_POSITION)|(0x08<<BITS_POSITION);

	//八位数据,主模式 关中断

    S0SPCCR = spiClock;

}

void Spi0SelectCs(void)

{

	FIO0CLR |= (1<<16);

}

void Spi0DisSelectCs(void)

{

    FIO0SET |= (1<<16);

}

u8 Spi0RwData(u8 writeByte,u8* readByte)

{

    u8 retry = 200;

    if((S0SPSR&0x80))

    {

        retry = S0SPDR;

        return 1;

    }

    S0SPDR = writeByte;

    retry = 200;

    while(!(S0SPSR&0x80))

    {

        retry--;

        if(retry == 0)return 1;

    }

    *readByte = S0SPDR;

    return 0;

}

void Spi0SetSpeed(SPI0_SPEED speed)

{

    u32 spiClock = (SystemCoreClock/4)/speed;

    S0SPCCR = spiClock;

}