spi.c

来自「ht1621 使用例程 驱动段码液晶 同时用诺基亚3310lcd做监控」· C语言 代码 · 共 36 行

/*****************************************************************************
*                                       SPI.c
*
*****************************************************************************/
#include <avr/io.h>  					//Included definitions for ATmega32
#include "SPI.h"

/*****************************************************************************
*           				SPI Definitions
*/
#define SPI_PORT			PORTB
#define SPI_DDR             DDRB		//Data direction register
#define SPI_PIN             PINB		//Port used for SPI
#define SPI_SS_NUM			(4)			//SPI Slave select, must be set as output
#define SPI_MOSI_NUM		(5)			//SPI CPU master output
#define SPI_MISO_NUM		(6)			//SPI CPU master input
#define SPI_SCK_NUM 		(7)			//SPI clock, CPU master

/*****************************************************************************
* WriteReadSPI: Send character to SPI and return character read back
*/
void InitSPI(void)
{
  	SPI_DDR = SPI_DDR | (1<<SPI_SCK_NUM);		//Set port as output
  	SPI_DDR = SPI_DDR | (1<<SPI_MOSI_NUM);		//Set port as output 	
  	//MISO always set as input in master mode
//  	SPI_DDR = SPI_DDR | (1<<SPI_SS_NUM);		//Set port as output, low at input will disable master mode
//  	SPI_PORT = SPI_PORT & (~(1<<SPI_MISO_NUM));	//Turn off pull-up
		/* Enable SPI, Master, set clock rate fck/16 */
		SPSR |= (1<<SPI2X);                 // 设置SPI时钟倍速
    SPCR |= (1<<SPE)|(1<<MSTR);		// 使能SPI接口，主机模式，4M时钟
 
}