etpuc_pwm.c

mpc55**系列芯片的例程 包括SCI,SPI,TIMER,FIT,EDMA等几乎所有功能的实现

/****************************************************************************
 * FILE NAME: etpuc_pwm.c                      COPYRIGHT (c) Freescale 2004 *
 * DESCRIPTION:                                     All Rights Reserved     *
 * This function generals a PWM (Pulse Width Modulated) waveform in which   *
 * the frequency and duty can be changed at any time by the CPU. The        *
 * function can generate 0% and 100% output. The function uses both actions *
 * on the channel hardware so it can generate small output pulses.          *
 *==========================================================================*
 * ORIGINAL AUTHOR: Jeff Loeliger [r12110] ([e-mail])    *
 * $Log: etpuc_pwm.c,v $
 * Revision 1.5  2004/11/02 14:11:16  r12110
 * -Fixed possible problem with comments in auto generated file.
 *
 * Revision 1.4  2004/11/02 13:49:59  r12110
 * -Added standard support for building function stand alone or in a set.
 * -Updated comments in auto generated file to include version number.
 *
 * Revision 1.3  2004/11/02 10:20:27  r12110
 * -Added support for building function stand alone or in a set.
 *   -This includes using the global error function if avaialable.
 * -Change PWM_flag to just Flag, since it is local to function.
 * -Added comments about Flag parameter.
 * -Updated comments in auto generated file to include version number.
 *
 * Revision 1.2  2004/11/01 15:13:46  r12110
 * Updated with new CVS log style comments.
 *
 *..........................................................................*
 * 0.01  J. Loeliger  02/Feb/04  Initial version of file.                   *
 * 0.02  J. Loeliger  12/Feb/04  Updated comments. Removed clear trans-     *
 *                                 latch in S6, it is better if this is     *
 *                                 handled by the error function.           *
 * 0.03  J. Loeliger  17/Feb/04  Updated after review/feedback from Milan   *
 *                                Added mrlA test in S2 and added code in S3*
 *                                because of compiler issue.                *
 * 1.00  J. Loeliger  25/May/04  Changed from Motorola to Freescale.        *
 *                               Changed all comments to standard C style.  *
 *                               Fixed problem in S0 when using TCR2, first *
 *                                edge was based on TCR1.                   *
 *                               Added EnableOutputBuffer(); in S0.         *
 *                               Added PWM_ prefix to macros to prevent     *
 *                                problems when used with other functions.  *
 *                               Changed to standard error routine for      *
 *                                unused entry points.                      *
 *                               Combined S1 & S2. The pin condition can not*
 *                                be used in the entry because it might not *
 *                                be connected to the output.               *
 *                               Fixed problem if 0% was selected during    *
 *                                init. 100% was generated for first period.*
 *                                Reworked S0 and combined with S4 & S5.    *
 * 1.01  J. Loeliger   1/Jun/04  Changed the idle state if the selected TCR *
 *                                is not running from active state to in-   *
 *                                active state [erta=tcrx->erta=tcrx+1]     *
 * 1.02  J. Loeliger  21/Jun/04  Swapped flag0 & flag1 to fix problem with  *
 *                                immediate update mode. More optimizations.*
 * 1.03  J. Loeliger  25/Jun/04  Added option comment in auto generated file*
 *                                for the CGT.                              *
 * 1.04  J. Loeliger  16/Jul/04  Added S2 back in. It recalcuates the edge  *
 *                                for the next frame.                       *
 * 1.05  J. Loeliger  19/Jul/04  Coherent update fix. Had to add a new flag *
 *                                parameter so coherent update can test the *
 *                                value in flag0.                           *
 * 1.1   J. Loeliger  25/Oct/04    Initial version checked into CVS.        *
 ****************************************************************************/
#ifndef __ETPUC_H
#include <etpuc.h>          /*Defines eTPU hardware*/
#endif

#ifndef __ETPUC_COMMON_H
#include <eTPUc_common.h>   /*Standard way to use eTPU*/
#endif

#ifdef PWM_FUNCTION_NUMBER    /* function is being compiled as part a set? */
#pragma ETPU_function PWM, alternate @ PWM_FUNCTION_NUMBER;
#else
#pragma ETPU_function PWM, alternate; /* stand alone */
#endif

/* Macros to make the code easier to understand. */
/* These are specific to this PWM function */
/* Host service requests */
#define PWM_INIT            7
#define PWM_IMMED_UPDATE    3
#define PWM_COHERENT_UPDATE 5

/*Function Modes */
#define PWM_USE_TCR1    0
#define PWM_ACTIVE_HIGH 1
#define PWM_ACTIVE_LOW  0

/****************************************************************************
* General Notes:
* 1. This function works with high and low active times so the edges are
*       called FrameEdge which determines the frequency and ActiveEdge
*       which determines the active time of the signal.
*
* Channel Flag usage
* Flag1 is a mirror of FunctionMode0 and defines if the PWM is active high
*    or active low. It is used an entry condition. Flag1=1 for normal high
*    active PWM.
* Flag0 is used to define which edge should occur next. The problem is that
*    for very small high or low pulses both matches can get set and they
*    need to be serviced in a particular order.
*    0 = Match2 next and 1 = Match1 next.
****************************************************************************/

/*--------------------------------------------------------------------------+
| FUNCTION PARAMETERS:                                                      |
| Flag: Is a mirror of Flag0 so that it can be testing in a thread.         |
| Period: Determines the period of the output signal. It is the number of   |
|     selected TCR tick. The maximum valid value is 0x80 0000 and the       |
|     minimum useful value will depend on eTPU loading.                     |
| ActiveTime: Determines the active time of the output signal. It is the    |
|     number of TCR ticks. The maximum valid value is equal to the Period   |
|     and the minimum value is 0.                                           |
| Coherent_Period: Period value used for coherent update of period and      |
|     active time.                                                          |
| Coherent_ActiveTime: Period value used for coherent update of period and  |
|     active time.                                                          |
+--------------------------------------------------------------------------*/
void PWM(int8 Flag, int24 Period, int24 ActiveTime, int24 Coherent_Period,
        int24 Coherent_ActiveTime )
{
	static int24 LastFrame;
	static int24 NextEdge;

/*--------------------------------------------------------------------------+
| THREAD NAME: Initialize (S0)                                              |
| DESCRIPTION: Initialize a channel to run the PWM function.                |
|              1. Disable matches in thread in case there are any previous  |
|                  pending matches. This could happen if the channel was    |
|                  running another function before this one.                |
|              2. Configure channel for active high or low signal.          |
|              3. Configure channel to use TCR1 or TCR2.                    |
|              4. Configure first match and channel mode.                   |
|              5. Clear latches.                                            |
|              6. Set flag0 to do match1 next. This will happen immediately |
|                  because it has been scheduled for the current TCR count. |
+--------------------------------------------------------------------------*/
	if ( HostServiceRequest == PWM_INIT )
	{
		DisableMatchesInThread();
		OnTransA( NoDetect );
		OnTransB( NoDetect );
		Clear ( TransLatch );
		Clear ( LSRLatch );
		EitherMatchNonBlockingSingleTransition();
		Set (flag0);			/*after init frame edge should be serviced 1st*/
		Flag = Flag | 1;

		ActionUnitA( MatchTCR2, CaptureTCR2, GreaterEqual);
		ActionUnitB( MatchTCR2, CaptureTCR2, GreaterEqual);
		erta = tcr2 + 1;
		if ( FunctionMode1 == PWM_USE_TCR1 )
		{
				ActionUnitA( MatchTCR1, CaptureTCR1, GreaterEqual);
				ActionUnitB( MatchTCR1, CaptureTCR1, GreaterEqual);
				erta = tcr1 + 1;
		}
		ertb = erta + ActiveTime;
		NextEdge = ertb;
		ConfigMatch_AB();
		if ( FunctionMode0 == PWM_ACTIVE_HIGH )
		{
			SetPinLow(); /*Active high so set pin low to start.*/
 		    EnableOutputBuffer();
			OnMatchB( PinLow );
			Set( flag1 );
			goto PWM_Frame;
		}
		else
		{
			SetPinHigh(); /*Active low so set pin low to start.*/
   		    EnableOutputBuffer();
			Clear( flag1 );
			OnMatchB( PinHigh );
			goto PWM_Frame2;
		}
	}
/*--------------------------------------------------------------------------+
| THREAD NAME: Immediate Update (S1)                                        |
| DESCRIPTION: This is used to change the active time of a channel during   |
|                 the current period. The NextEdge time is calculated and   |
|                 then scheduled.                                           |
|              1. Check if ActiveEdge match has occured, if so just end.    |
|              2. Reschedule the ActiveEdge.                                |
+--------------------------------------------------------------------------*/
	else if ( HostServiceRequest == PWM_IMMED_UPDATE  && flag0==0)
	{
		NextEdge = LastFrame + ActiveTime;
		ertb = NextEdge - Period;
		WriteErtBToMatchBAndEnable();