ad.c

瑞萨CAN通讯单片机程序

/*""FILE COMMENT""*****************************************************
 *	M32R C Programming		Rev. 1.00
 *		 < Sample Program for AD converter >
 *
 *	Copyright (c) 2003 Renesas Technology Corporation
 *			   And Renesas Solutions Corporation
 *			   All Rights Reserved
 *********************************************************************/

/************************************************************************/
/*		Include file						*/
/************************************************************************/

#include		"..\inc\sfr32170_pragma.h"

/************************************************************************/
/*		Function prototype declaration				*/
/************************************************************************/

	unsigned short	AD0exe( unsigned char );		/* Execute AD conversion */

/************************************************************************/
/*		Define macro						*/
/************************************************************************/

						/* 0123 4567	*/
#define	ADSIM0_ini	(unsigned char)0x01	/* 0000 0001B	*/
						/* |||| |||+---- AD conversion start		*/
						/* |||| ||+----- No operation			*/
						/* |||| |+------ don't care			*/
						/* |||| +------- No DMA transfer request	*/
						/* ||++--------- Software trigger		*/
						/* ++----------- don't care			*/

						/* 0123 4567	*/
#define	ADSIM1_ini	(unsigned char)0x40	/* 0100 0000B	*/
						/* |||| ++++---- AD0 selected			*/
						/* |||+--------- don't care			*/
						/* ||+---------- Analog extension unused	*/
						/* |+----------- Double speed			*/
						/* +------------ AD conversion mode		*/

/*""FUNC COMMENT""*******************************************************
 * Function name: AD0exe()
 *-----------------------------------------------------------------------
 * Description	: AD conversion using AD0
 *		: - Executes AD conversion on the channel specified with 
 *              :   the argument and returns the conversion result
 *-----------------------------------------------------------------------
 * Argument	: unsigned char AD0ch	AD0 converter channel number on which to convert
 *-----------------------------------------------------------------------
 * Returns	: 10-bit AD conversion result
 *-----------------------------------------------------------------------
 * Notes	: - Only the 4 low-order bits of the channel number are used
 *		: - More than 1 cycle of wait time (dummy wait cycles) is 
 *              :   required when starting AD conversion and reading out 
 *              :   the AD conversion-finished bit
 *		: - Wait until AD conversion finishes
 *""FUNC COMMENT END""***************************************************/
unsigned short	AD0exe( unsigned char AD0ch)
{
	unsigned long	j;
	unsigned short	*AdDtPtr;

	AD0ch &= 0x0f;				/* Use only the 4 low-order bits of channel number */

	AdDtPtr = (unsigned short *)&AD0DT0;	/* Start address of AD0 conversion result register */

	AD0SIM1 = ADSIM1_ini | AD0ch;		/* Select single mode and channel */
	AD0SIM0 = ADSIM0_ini;			/* Start AD conversion */

	for( j = 0; j < 1; j++);		/* Dummy wait cycle until reading out the AD conversion-finished bit */
	while( !( AD0SIM0 & AD0SCMP));		/* Wait until AD conversion finishes */

	return( *(AdDtPtr + AD0ch));		/* Read out conversion result */
}