hndshake.c

CML CMX868 modem

//---------------------------------------------------------------------------------------------------
//	Project:-	DE8681
//  	Filename:-	HNDSHAKE.C
//	Description:-	Handshaking Routines for CMX868.
//	Programmer:-	D.T.F	
//	Version:-	2.0
//	Created:-	28th February 2002
//	Last modified:- 
//---------------------------------------------------------------------------------------------------
//	(C) Consumer Microcircuits Ltd 2002
//
//	This firmware was designed by:-
//			Consumer Microcircuits Ltd,
//			Langford, Maldon,
//			ESSEX
//			CM9 6WG.
//	in the UK for use with CML evaluation kits only and is based on UK originated technology.
//	Please contact
//			[e-mail]
//			[phone]
//	for licensing details.
//---------------------------------------------------------------------------------------------------

#define HNDSHAKE_C

#include	"ef8681.h"

void hndshake_init()
{
	reset_cbus();						// Reset the CBUS before we start, will clear all shadow write registers
	pwrup();						// Power Up CMX868 with correct Xtal and fixed equalisers initially enabled.

	CMXTXMODE ^= (((int) S25) << 9) & 0x0E00;		// Extract required Tx level from S25.
	wr16_cbus(CMXTXMODE_ADDR, CMXTXMODE);			// Update CBUS register

	CMXRXMODE ^= (((int) S26) << 9) & 0x0E00;		// Extract required Rx level from S26.
	wr16_cbus(CMXRXMODE_ADDR, CMXRXMODE);			// Update CBUS register

	FIX_EQU = USER_FIX_EQU;					// Extract required Tx and Rx Fixed Equaliser settings from S24.
	wr16_cbus(CMXGENCTRL_ADDR, CMXGENCTRL);			// Update CBUS register
}

unsigned char hndshake_go()
{
	unsigned char	tmpresult;

	if (ANSORIG)						// Check S14 Bit 7, if set we are originating a call
	{
		GPT6 = S7;					// Load GPT6 (1s) with Wait for carrier after dial S-Register

		switch(S27 & 0b11110000)
		{
			case PROTB0: case PROTB1:
				tmpresult = orig_V22bis();
				break;
			case PROTB2:
				tmpresult = orig_V23();
				break;
			case PROTB3:
				tmpresult = orig_V23r();
				break;
			case PROTB4:
				tmpresult = orig_V22_600();
				break;
			case PROTB5:
				tmpresult = orig_V21();
				break;
			case PROTB6:
				tmpresult = orig_212a();
				break;
			case PROTB7:
				tmpresult = orig_202();
				break;
			case PROTB8:
				tmpresult = orig_202r();
				break;
			case PROTB9:
				tmpresult = orig_103();
				break;
			default:
				return(ERROR);			// Indicate Error has occured 
		}
	}
	else
	{
		GPT6 = S18;					// Load GPT6 (1s) with General Purpose timer setting

		switch(S27 & 0b11110000)
		{
			case PROTB0: case PROTB1:
				ans_tone();
				tmpresult = ans_V22bis();
				break;
			case PROTB2:
				ans_tone();
				tmpresult = ans_V23();
				break;
			case PROTB3:
				ans_tone();
				tmpresult = ans_V23r();
				break;
			case PROTB4:
				ans_tone();
				tmpresult = ans_V22_600();
				break;
			case PROTB5:
				ans_tone();
				tmpresult = ans_V21();
				break;
			case PROTB6:
				tmpresult = ans_212a();
				break;
			case PROTB7:
				tmpresult = ans_202();
				break;
			case PROTB8:
				tmpresult = ans_202r();
				break;
			case PROTB9:
				tmpresult = ans_103();
				break;
			default:
				return(ERROR);			// Indicate Error has occured
		}
	}
	if ((tmpresult != NYI) && (tmpresult != NOCARRIER))
	{
		DATAXFER = 1;
		ATCMDMODE = 0;

		switch(S22 & 0b11100000)
		{
			case X0CALLING:
				return(CONNECT);
			default:
				return(tmpresult);
		}
	}
	else
	{
		return(tmpresult);	
	}
}

unsigned char orig_V22bis()
{
	unsigned char det32ones = 0;
	unsigned char tx2400flag = 0;
	unsigned char gotS1pattern = 0;

// Stage 1 Look for unscrambled 1's or 2225Hz tone
	CMXRXMODE &= 0x0E00;					// Mask Rx Gain settings 
	CMXRXMODE ^= 0x1002;					// Setup Rx for 2225Hz Answer Tone Detection (will detect unscram 1's)
	wr16_cbus(CMXRXMODE_ADDR, CMXRXMODE);			// Update Rx Mode CBUS register

	GPT1 = 12;						// Start 150ms timer (Answer Tone detector has approx 30ms response time)

	do {
		DelayMs(5);					// Insert 5ms polling delay 
		if (KEYABORT || (GPT6 == 0))
		{						// Return No Carrier message if key pushed or
			return(NOCARRIER);			// if wait carrier after dial timer has expired
		}
		CMXSTAT = rd16_cbus(CMXSTAT_ADDR);		// Read status register and update shadow register
		if (!ANS2225DET)				// If 2225Hz Answer Tone is not detected
		{
			GPT1 = 12;				// Restart 2225Hz Answer Tone detect timer
		}
	} while(GPT1 != 0);					// Continue to loop until unscram 1's detected for approx 150ms

// Stage 2 Wait for 450ms
	CMXRXMODE &= 0x0E00;					// Mask Rx Gain settings 
	CMXRXMODE ^= 0xD0F8;					// Setup Rx for high band V.22 1200bps, auto-equaliser disabled,
								// Descrambler enabled and synchronous operation
	wr16_cbus(CMXRXMODE_ADDR,CMXRXMODE);			// Update Rx Mode CBUS register

	GPT1 = 45;						// Start 450ms timer

	do {
		if (KEYABORT || (GPT6 == 0))
		{						// Return No Carrier message if key pushed or
			return(NOCARRIER);			// if wait carrier after dial timer has expired
		}
	} while (GPT1 != 0);

// Stage 3 Tx S1 Pattern if V22bis selected
	if ((S27 & 0b11110000) == PROTB0) 
	{
		CMXTXMODE &= 0x0E00;				// Mask Tx Gain settings 
		CMXTXMODE ^= 0xC018;				// Initially setup Tx for low band V.22 1200bps, no guard tone
								// No Guard tone, scrambler Disabled, synchronous operation and Tx S1 pattern
		wr16_cbus(CMXTXMODE_ADDR, CMXTXMODE);		// Update Tx Mode CBUS register

		GPT1 = 10;					// Start 100ms timer
		do {
			if (KEYABORT || (GPT6 == 0))
			{					// Return No Carrier message if key pushed or
				return(NOCARRIER);		// if wait carrier after dial timer has expired
			}
		} while(GPT1 !=0);				// Wait for 100ms timer to expire
	}

// Stage 4 Tx 1200bps scrambled 1's
	CMXTXDATA = 0xFF;
	wr_cbus(CMXTXDATA_ADDR, CMXTXDATA);			// Ensure Tx data reg is all 1's

	CMXTXMODE &= 0x0E00;					// Mask Tx gain settings
	CMXTXMODE ^= 0xC07F;					// Setup Tx for low band V.22 1200bps, no guard tone
								// Scrambler enabled, sync operation and Tx data byte reg
	wr16_cbus(CMXTXMODE_ADDR,CMXTXMODE);			// Update Tx Mode CBUS register

// Stage 5 Look for S1 pattern if V22bis selected
	if ((S27 & 0b11110000) == PROTB0)
	{
		GPT1 = 27;					// Start 270ms timer

		do {
			DelayMs(5);				// Insert 5ms polling delay 
			if (KEYABORT || (GPT6 == 0))
			{					// Return No Carrier message if key pushed or
				return(NOCARRIER);		// if wait carrier after dial timer has expired
			}
			CMXSTAT = rd16_cbus(CMXSTAT_ADDR);	// Read status register and update shadow register
			if (RXENERGYDET && S1DET)
			{
				gotS1pattern = 1;		// Set flag to indicate S1 pattern was found
			}
		} while((GPT1 != 0) && !gotS1pattern);		// Continue to loop until timer expires or S1 pattern is detected
	}

	if (gotS1pattern)
	{
// Stage 6 If the S1 pattern was detected wait until it goes away 
		do {
			DelayMs(5);				// Insert 5ms polling delay 
			if (KEYABORT || (GPT6 == 0))
			{					// Return No Carrier message if key pushed or
				return(NOCARRIER);		// if wait carrier after dial timer has expired
			}
			CMXSTAT = rd16_cbus(CMXSTAT_ADDR);	// Read status register and update shadow register
		} while(S1DET);					// Wait until S1 Pattern has gone
// Stage 7
		GPT1 = 60;					// Start 600ms timer

		do {
			if (KEYABORT || (GPT6 == 0))
			{					// Return No Carrier message if key pushed or
				return(NOCARRIER);		// if general purpose timer (S18) has expired
			}
		} while (GPT1 >= 30);				// Wait until 300ms has expired

		AUTO_EQU = 1;					// Enable Rx Auto-Equaliser for training (must be enabled for 2400bps operation)
		wr16_cbus(CMXRXMODE_ADDR, CMXRXMODE);		// Update Rx Mode CBUS register	

		do {
			if (KEYABORT || (GPT6 == 0))
			{					// Return No Carrier message if key pushed or
				return(NOCARRIER);		// if wait carrier after dial timer has expired
			}
		} while (GPT1 >= 15);				// Wait until 450ms has expired

// Stage 8 Switch Rx Mode to 2400bps (Detectors and associated status flags will be reset)
		CMXRXMODE &= 0x0FFF;				// Unmask Rx Mode bit settings
		CMXRXMODE ^= 0xF000;				// Setup Rx for high band V.22bis 2400bps
		wr16_cbus(CMXRXMODE_ADDR, CMXRXMODE);		// Update Rx Mode CBUS register

// Stage 9 Wait until 32 continuous 1's are detected and transmitter has switched to 2400bps scram 1's
		do {
			DelayMs(5);				// Insert 5ms polling delay 
			if (KEYABORT || (GPT6 == 0))
			{					// Return No Carrier message if key pushed or
				return(NOCARRIER);		// if wait carrier after dial timer has expired
			}
			if (!tx2400flag)
			{
				if (GPT1 == 0)			// Check if 600ms timer has expired
				{
					CMXTXMODE &= 0x0FFF;	// Unmask Tx Mode bit settings
					CMXTXMODE ^= 0xE000;	// Setup Tx for low band V.22 bis 2400bps
					wr16_cbus(CMXTXMODE_ADDR, CMXTXMODE);	// Update Tx Mode CBUS register	

					GPT1 = 20;		// Load 200ms Timer
					tx2400flag = 1;
				}
			}
			CMXSTAT = rd16_cbus(CMXSTAT_ADDR);	// Read status register and update shadow register

			if (RXENERGYDET && CONTA && CONTB && !det32ones)
			{
				DCDN = 0;			// Clear DCDN line.
				DCDIND = 1;			// Turn on CD LED.
				det32ones = 1;			// Set detect 32 1's flag
			}
		} while(!RXENERGYDET || !CONTA || !CONTB || !tx2400flag);	// Wait until 2400bps cont 1's is detected and
										// 2400bps has started transmitting
// Stage 10 Ensure final 200ms timer has expired
		do {
			if (KEYABORT || (GPT6 == 0))
			{					// Return No Carrier message if key pushed or
				return(NOCARRIER);		// if wait carrier after dial timer has expired
			}
		} while (GPT1 != 0);				// Ensure 200ms timer has expired
	}
	else
	{
		if (((S27 & 0b11110000) == PROTB0) && !FALLBACK)
		{
			return(NOCARRIER);			// Return No Carrier message
		}

// Stage 11 Detect scrambled 1's for 270ms
		GPT1 = 24;					// Start 270ms timer (scram 1's detect has approx 30ms (32 bits) response time)

		do {
			DelayMs(5);				// Insert 5ms polling delay 
			if (KEYABORT || (GPT6 == 0))
			{					// Return No Carrier message if key pushed or
				return(NOCARRIER);		// if wait carrier after dial timer has expired
			}
			CMXSTAT = rd16_cbus(CMXSTAT_ADDR);	// Read status register and update shadow register
			if (!RXENERGYDET || !CONTA || !CONTB)	// If rx energy or scram 1's are not detected
			{
				GPT1 = 24;			// Restart scram 1's detect timer
			}
		} while(GPT1 != 0);				// Continue to loop until scram 1's detected for approx 270ms

		AUTO_EQU = USER_AUTO_EQU;			// Extract Auto Equaliser setting from S24.
		wr16_cbus(CMXRXMODE_ADDR,CMXRXMODE);		// Update Rx Mode CBUS register	

		DCDN = 0;					// Clear DCDN line.
		DCDIND = 1;					// Turn on CD LED.

// Stage 12 Start 770ms timer
		GPT1 = 77;
		do {
			if (KEYABORT || (GPT6 == 0))
			{					// Return No Carrier message if key pushed or
				return(NOCARRIER);		// if wait carrier after dial timer has expired
			}
		} while (GPT1 != 0);				// Wait until 770ms has expired
	}
// Stage 13
	async_setup();						// Configure Tx/Rx for async operation (settings extracted from S25 and S26)

	if (!gotS1pattern)
	{
		return(CON1200);				// Return Connect 1200
	}
	else
	{
		return(CON2400);				// Return Connect 2400
	}
}

unsigned char orig_V23()
{
// Stage 1
	CMXRXMODE &= 0x0E00;					// Mask Rx Gain settings
	CMXRXMODE ^= 0x5038;					// Setup Rx for V23 1200bps and auto-equaliser disabled
								// Descrambler Disabled, synchronous operation
	wr16_cbus(CMXRXMODE_ADDR,CMXRXMODE);			// Update Rx Mode CBUS register

	if (unscram1sdet(12) != OK) return(NOCARRIER);		// Detect unscram 1's for 150ms (1's detect has approx 30ms (32bits) response time)

// Stage 2
	DCDN = 0;						// Clear DCDN line.
	DCDIND = 1;						// Turn on CD LED.

	GPT1 = 77;						// Start 770ms timer

	do {
		if (KEYABORT || (GPT6 == 0))
		{						// Return No Carrier message if key pushed or
			return(NOCARRIER);			// if wait carrier after dial timer has expired
		}
	} while (GPT1 >= 32);					// Wait until 450ms has expired

// Stage 3
	CMXTXDATA = 0xFF;
	wr_cbus(CMXTXDATA_ADDR,CMXTXDATA);			// Ensure Tx data reg is all 1's

	CMXTXMODE &= 0x0E00;					// Mask Tx Gain Settings
	CMXTXMODE ^= 0x401F;					// Setup Tx for V23 75bps, no guard tone
								// No Guard tone, scram disabled, sync operation, Tx data byte reg
	wr16_cbus(CMXTXMODE_ADDR,CMXTXMODE);			// Update Tx Mode CBUS register
// Stage 4
	do {
		if (KEYABORT || (GPT6 == 0))
		{						// Return No Carrier message if key pushed or
			return(NOCARRIER);			// if wait carrier after dial timer has expired
		}
	} while (GPT1 != 0);					// Ensure 770ms timer has expired

// Stage 5
	async_setup();						// Configure Tx/Rx for async operation (settings extracted from S25 and S26)

	return(CON751200);					// Return Connect 75/1200
}

unsigned char orig_V23r()
{
	return(NYI);
}