/**************************************************************************
**                                                                        *
**  FILE        :  pwm.c                                                  *
**                                                                        *
**  DESCRIPTION :  Routines for controlling PWM	input to DC Drive motor	  *
**                 controller							                  *
**                                                                        *
**  COPYRIGHT   :  2000 Monterey Bay Aquarium Research Institute          *
**                                                                        *
**	REVISION HISTORY:													  *
**		1.0.0	Initial release (prm)									  *
**************************************************************************/

#ifndef PRECOMPHDRS
#include	<TT8.h>			/* Tattletale Model 8 Definitions */
#include	<tat332.h>		/* 68332 Tattletale (7,8) Hardware Definitions */
#include	<tpu332.h>		/* 68332 Time Processing Unit Definitions */

#include	<tt8lib.h>		/* definitions and prototypes for Model 8 library */
#endif
#include	<pwm.h>
#include	<instrument.h>


/*******************************************************************************
**	TPUSetupPWM			Setup TPU channel for Pulse-Width Modulation
**	
**	Notes:
**		pwmper = period in tcr1 cycles [call TPUGetTCR1() for current cycles/sec]
**		with default TPU setup and TT8 clock at 16 MHz, one tcr1 cycle is 250 ns
**		pwmhi = time high in tcr1 cycles
**		priority = LowPrior, MiddlePrior, or HighPrior [defined in tpu.h]
**		read about value limitations in the TPU Reference Manual
*******************************************************************************/
void TPUSetupPWM(short chan, short pwmhi, short pwmper, short priority)
	{
	
	CHANPRIOR(chan, Disabled);			/* stop what it's doing */
	if (priority == Disabled)			/* just shutting it down */
		return;
	*CIER &= ~(1 << chan);				/* don't want interrupts enabled */
	FUNSEL(chan, PWM);					/* channel function select */
	PRAM[chan][0] = OutputChan | NoChangePAC | (pwmhi ? ForceHigh : ForceLow);
	PRAM[chan][2] = pwmhi;				/* time hi */
	PRAM[chan][3] = pwmper;				/* period */

	HOSTSERVREQ(chan, 2);				/* issue request */
	CHANPRIOR(chan, priority);			/* set channel priority */
	while (HOSTSERVSTAT(chan) & 3)		/* await reply */
		;
	
	} /* TPUSetupPWM() */


/*******************************************************************************
**	TPUChangePWM			Change PWM values for inited TPU channel
**	
**	Notes:
**		pwmper = period in tcr1 cycles [call TPUGetTCR1() for current value]
**		pwmhi = time high in tcr1 cycles
*******************************************************************************/
void TPUChangePWM(short chan, short pwmhi, short pwmper)
	{

/*
**	NEED TO DO THIS WRITE COHERENTLY (AS DOUBLE WRITE)
*/
	* (ulong *) &PRAM[chan][2] = ((ulong) pwmhi << 16L) | (ulong) pwmper;
	HOSTSERVREQ(chan, 1);				/* issue request */
	while (HOSTSERVSTAT(chan) & 3)		/* await reply */
		;

	} /* TPUChangePWM() */