www.pudn.com > armexamples.rar > spi_cmd.c

/* 
 
Module Name:	SPI_CMD.C 
 
Abstract:		Function definition for the CAN's spi command interface 
   
Notes:			Presently, only the SPI Channel 0 is supported. 
 
Environment:	MCP2515 
 
Date: 			2004/01/28 
 
By: 			Li zhongmin 
    
*/  
 
#include 	"spi.h" 
#include	"spi_cmd.h" 
 
unsigned char CAN_SPI_CMD( unsigned char cmd, unsigned long addr, unsigned char arg1, unsigned char arg2 ) 
{ 
	unsigned char ret=0; 
	unsigned char data=0;	 
 
	// Empty the spi's transfer and receive buffer 
	// SPI_TXFlush( CAN_SPI_MODULE ); 
	// SPI_RXFlush( CAN_SPI_MODULE ); 
	 
	//StartSPIClock(); 
	rGPGDAT &= CHIP_SELECT_nSS0; 
 
	switch( cmd ){ 
		case SPI_CMD_READ: 
			 
			ret = SPI_SendByte(SPI_CMD_READ, &data); 
			ret = SPI_SendByte(addr, &data);			 
			ret = SPI_SendByte(0xff, &data);	 
			 
			break; 
			 
		case SPI_CMD_WRITE: 
		 
			ret = SPI_SendByte(SPI_CMD_WRITE, &data); 
			ret = SPI_SendByte(addr, &data); 
			ret = SPI_SendByte(arg1, &data);	 
						 
			break; 
		case SPI_CMD_RTS: 
			 
			ret = SPI_SendByte(SPI_CMD_RTS, &data); 
			 
			break; 
		case SPI_CMD_READSTA: 
			 
			ret = SPI_SendByte(SPI_CMD_READSTA, &data); 
			ret = SPI_SendByte(0xff, &data);			 
			 
			break; 
		case SPI_CMD_BITMOD: 
			 
			ret = SPI_SendByte(SPI_CMD_BITMOD, &data); 
			ret = SPI_SendByte(addr, &data); 
			ret = SPI_SendByte(arg1, &data);	 
			ret = SPI_SendByte(arg2, &data);				 
			 
			break; 
		case SPI_CMD_RESET: 
			ret = SPI_SendByte(SPI_CMD_RESET, &data); 
			break; 
		default: 
			ret = 0x30;										// any value is ok 
	} 
	 
	rGPGDAT |= CHIP_DESELECT_nSS0; 
 	//StopSPIClock(); 
			  
	//SPI_RXFlush( CAN_SPI_MODULE ); 
	 
	return data; 
}