/* -*- mode: C++; tab-width: 4 -*- */
/* ===================================================================== *\
	Copyright (c) 2000-2001 Palm, Inc. or its subsidiaries.
	All rights reserved.

	This file is part of the Palm OS Emulator.

	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.
\* ===================================================================== */

#include "EmCommon.h"
#include "EmSPISlave330Current.h"

#include "Logging.h"
#define PRINTF	if (1) ; else LogAppendMsg


/*****************************************************************************
 * The HandEra 330 includes a battery current sense.  It is switched in and
 * out of channel 2 of the ADC.
 ****************************************************************************/

// ---------------------------------------------------------------------------
//		¥ EmSPISlave330Current::EmSPISlave330Current
// ---------------------------------------------------------------------------

EmSPISlave330Current::EmSPISlave330Current () :
	EmSPISlave (),
	fBitBufferIn (0),
	fBitBufferOut (0),
	fNumBitsIn (0),
	fPendingResult (0),
	fHavePending (false),
	fCommandBitsSeen (0),
    fPowerConnected(false)
{
}


// ---------------------------------------------------------------------------
//		¥ EmSPISlave330Current::~EmSPISlave330Current
// ---------------------------------------------------------------------------

EmSPISlave330Current::~EmSPISlave330Current (void)
{
}

// ---------------------------------------------------------------------------
//		¥ EmSPISlave330Current::DoExchange
// ---------------------------------------------------------------------------

uint16 EmSPISlave330Current::DoExchange (uint16 control, uint16 data)
{
	PRINTF ("");
	PRINTF ("EmSPISlave330Current::DoExchange");
	PRINTF ("control = 0x%04X, data = 0x%04X", control, data);

	// -----------------------------------------------------------------------
	// Merge the incoming bits with our current buffer.
	// -----------------------------------------------------------------------

	uint16	numBits			= (control & hwrVZ328SPIMControlBitsMask) + 1;
	uint32	oldBitsMask		= ~0 << numBits;
	uint32	newBitsMask		= ~oldBitsMask;

	PRINTF ("Before merging input:   fBitBufferIn = 0x%04X, fNumBitsIn = 0x%04X", fBitBufferIn, fNumBitsIn);

	fBitBufferIn = ((fBitBufferIn << numBits) & oldBitsMask) | (data & newBitsMask);
	fNumBitsIn += numBits;

	PRINTF ("After merging input:    fBitBufferIn = 0x%04X, fNumBitsIn = 0x%04X", fBitBufferIn, fNumBitsIn);

	// -----------------------------------------------------------------------
	// Start processing the command bits.
	// -----------------------------------------------------------------------

	EmAssert (fNumBitsIn - fCommandBitsSeen - 1 >= 0);

	uint16	result	= 0;
	uint32	mask	= 1 << (fNumBitsIn - fCommandBitsSeen - 1);

	while (mask)
	{
		// Shift out a bit.

		{
			result = (result << 1) | (fBitBufferOut >> 15);
			fBitBufferOut <<= 1;
		}

		// If we haven't seen the Start bit yet, look for it.

		if (fCommandBitsSeen == 0)
		{
			// If we found the Start bit, start counting the
			// number of command bits as we stream through them.

			if ((mask & fBitBufferIn) != 0)
			{
				fCommandBitsSeen++;
			}

			// Otherwise, adjust fNumBitsIn so that when we *do*
			// find the Start bit, we know where it is.

			else
			{
				fNumBitsIn--;
			}

			// If there's a pending conversion, load it into the
			// output shift register after receiving the first
			// bit after the last bit of the previous command.

			this->LoadPendingConversion ();
		}
		else
		{
			fCommandBitsSeen++;

			// If we've seen 8 bits, process the command, and then
			// prepare for the next one.

			if (fCommandBitsSeen == 8)
			{
				fNumBitsIn			-= 8;
				fCommandBitsSeen	= 0;

				uint8	command		= fBitBufferIn >> fNumBitsIn;
				this->ProcessCommand (command);

				PRINTF ("After ProcessCommand:   fPendingResult = 0x%04X", fPendingResult);
			}
		}

		mask >>= 1;
	}


	// ----------------------------------------------------------------------
	// Return the result.
	// ----------------------------------------------------------------------

	PRINTF ("result = 0x%04X", result);

	return result;
}


// ---------------------------------------------------------------------------
//		¥ EmSPISlave330Current::ProcessCommand
// ---------------------------------------------------------------------------

void EmSPISlave330Current::ProcessCommand (uint8 command)
{
	uint16	result = 0;

    // we should only get here for channel 2
	EmAssert (((command & kChannelBits) >> 4) == 2);

    if (fPowerConnected)
        result = 0;    // no battery current with ext power connected.
    else
        result = 0x60; // just hard code some current for now.

	fPendingResult = result << 4;
	fHavePending = true;
}


// ---------------------------------------------------------------------------
//		¥ EmSPISlave330Current::LoadPendingConversion
// ---------------------------------------------------------------------------

void EmSPISlave330Current::LoadPendingConversion (void)
{
	// -----------------------------------------------------------------------
	// If there's a pending conversion, move it into the output shift register.
	// -----------------------------------------------------------------------
	if (fHavePending)
	{
		fHavePending	= false;
		fBitBufferOut	= fPendingResult;
	}
}