dalib.c

Vxworks的培训教程,大家分享下啊,

#include "daLib.h"

IMPORT DAADIO daadio;

STATUS dac (channel, volts)
	int channel;
	double volts;
	{
	USHORT *pChannel;

	/* Error checking */
	if (daadio.initialized == FALSE)
		{
		printf ("Daadio not initialized\n");
		return (ERROR);
		}

	if (channel < 0 || channel > DA_MAX_CHANNELS)
		{
		printf ("Channel number out of range\n");
		return (ERROR);
		}
	if (volts < MIN_VOLTAGE || volts > MAX_VOLTAGE)
		{
		printf ("volts out of range\n");
		return (ERROR);
		}
	
	/* Initializes <pChannel> to point to appropriate channel */
	pChannel = (USHORT *) (daadio.baseAddr + DA_OFFSET) + channel;

	/* Convert <volts> to 12-bit value and assign to channel register */
	*pChannel = (USHORT) (volts / 10 * 4095);

	return (OK);
	}