mirror of https://github.com/stella-emu/stella.git
Preliminary WIP for the Microchip Technology Inc. 24LC256, the EEPROM
used in the AtariVox and SaveKey. It isn't actually connected yet, and is basically a C++ wrapper around the I2C routines provided by J. Payson (aka Supercat). git-svn-id: svn://svn.code.sf.net/p/stella/code/trunk@1469 8b62c5a3-ac7e-4cc8-8f21-d9a121418aba
This commit is contained in:
stephena
parent
9608280880
commit
86a2a1dceb
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//============================================================================
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//
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// SSSS tt lll lll
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// SS SS tt ll ll
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// SS tttttt eeee ll ll aaaa
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// SSSS tt ee ee ll ll aa
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// SS tt eeeeee ll ll aaaaa -- "An Atari 2600 VCS Emulator"
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// SS SS tt ee ll ll aa aa
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// SSSS ttt eeeee llll llll aaaaa
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//
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// Copyright (c) 1995-2008 by Bradford W. Mott and the Stella team
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//
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// See the file "license" for information on usage and redistribution of
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// this file, and for a DISCLAIMER OF ALL WARRANTIES.
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//
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// $Id: MT24LC256.cxx,v 1.1 2008-04-13 15:05:58 stephena Exp $
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//============================================================================
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#include <cassert>
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#include <fstream>
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#include "Control.hxx"
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#include "System.hxx"
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#include "MT24LC256.hxx"
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/*
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State values for I2C:
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0 - Idle
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1 - Byte going to chip (shift left until bit 8 is set)
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2 - Chip outputting acknowledgement
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3 - Byte coming in from chip (shift left until lower 8 bits are clear)
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4 - Chip waiting for acknowledgement
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*/
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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MT24LC256::MT24LC256(const string& filename, const Controller* controller)
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: myController(controller),
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myDataFile(filename)
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{
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// First initialize the I2C state
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jpee_init();
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// Now load the data from an external file (if it exists)
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ifstream in;
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in.open(myDataFile.c_str(), ios_base::binary);
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if(in.is_open())
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{
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// Get length of file; it must be 32768
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in.seekg(0, ios::end);
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if((int)in.tellg() == 32768)
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{
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in.seekg(0, ios::beg);
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in.read((char*)myData, 32768);
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}
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in.close();
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}
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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MT24LC256::~MT24LC256()
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{
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// Save EEPROM data to external file
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ofstream out;
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out.open(myDataFile.c_str(), ios_base::binary);
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if(out.is_open())
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{
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out.write((char*)myData, 32768);
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out.close();
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}
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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bool MT24LC256::readSDA()
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{
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return jpee_mdat && jpee_sdat;
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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void MT24LC256::writeSDA(bool state)
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{
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#if 0
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if(state)
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(!jpee_mdat && jpee_sdat && jpee_mclk && (jpee_data_stop(),1), jpee_mdat = 1)
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else
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(jpee_mdat && jpee_sdat && jpee_mclk && (jpee_data_start(),1), jpee_mdat = 0))
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#endif
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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void MT24LC256::writeSCL(bool state)
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{
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#if 0
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if(state)
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jpee_mclk = 1;
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else
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(jpee_mclk && (jpee_clock_fall(),1), jpee_mclk = 0))
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#endif
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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void MT24LC256::jpee_init()
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{
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jpee_sdat = 1;
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jpee_address = 0;
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jpee_state=0;
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jpee_sizemask = 32767;
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jpee_pagemask = 63;
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jpee_smallmode = 0;
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jpee_logmode = -1;
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for(int i = 0; i < 256; i++)
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for(int j = 0; j < 128; j++)
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myData[i + j*256] = (i+1)*(j+1);
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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void MT24LC256::jpee_data_start()
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{
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/* We have a start condition */
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if (jpee_state == 1 && (jpee_nb != 1 || jpee_pptr != 3))
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{
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// JPEE_LOG0(LOG_UNCLEAN,"I2C_WARNING ABANDON WRITE");
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jpee_ad_known = 0;
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}
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if (jpee_state == 3)
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{
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// JPEE_LOG0(LOG_UNCLEAN,"I2C_WARNING ABANDON READ");
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}
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if (!jpee_timercheck(0))
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{
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// JPEE_LOG0(LOG_EVENTS,"I2C_START");
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jpee_state = 2;
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}
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else
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{
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// JPEE_LOG0(LOG_BUSY,"I2C_BUSY");
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jpee_state = 0;
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}
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jpee_pptr = 0;
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jpee_nb = 0;
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jpee_packet[0] = 0;
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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void MT24LC256::jpee_data_stop()
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{
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int i;
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if (jpee_state == 1 && jpee_nb != 1)
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{
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// JPEE_LOG0(LOG_UNCLEAN,"I2C_WARNING ABANDON_WRITE");
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jpee_ad_known = 0;
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}
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if (jpee_state == 3)
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{
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// JPEE_LOG0(LOG_UNCLEAN,"I2C_WARNING ABANDON_READ");
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jpee_ad_known = 0;
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}
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/* We have a stop condition. */
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if (jpee_state == 1 && jpee_nb == 1 && jpee_pptr > 3)
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{
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jpee_timercheck(1);
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// JPEE_LOG2(LOG_EVENTS,"I2C_STOP(Write %d bytes at %04X)",jpee_pptr-3,jpee_address);
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if (((jpee_address + jpee_pptr-4) ^ jpee_address) & ~jpee_pagemask)
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{
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jpee_pptr = 4+jpee_pagemask-(jpee_address & jpee_pagemask);
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// JPEE_LOG1(LOG_ODDBALL,"I2C_WARNING PAGECROSSING!(Truncate to %d bytes)",jpee_pptr-3);
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}
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for (i=3; i<jpee_pptr; i++)
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{
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myData[(jpee_address++) & jpee_sizemask] = jpee_packet[i];
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if (!(jpee_address & jpee_pagemask))
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break; /* Writes can't cross page boundary! */
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}
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jpee_ad_known = 0;
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}
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else
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;// JPEE_LOG0(LOG_EVENTS,"I2C_STOP");
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jpee_state = 0;
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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void MT24LC256::jpee_clock_fall()
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{
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switch(jpee_state)
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{
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case 1:
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jpee_nb <<= 1;
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jpee_nb |= jpee_mdat;
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if (jpee_nb & 256)
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{
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if (!jpee_pptr)
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{
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jpee_packet[0] = (unsigned char)jpee_nb;
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if (jpee_smallmode && ((jpee_nb & 0xF0) == 0xA0))
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{
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jpee_packet[1] = (jpee_nb >> 1) & 7;
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// if (jpee_packet[1] != (jpee_address >> 8) && (jpee_packet[0] & 1))
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// JPEE_LOG0(LOG_ODDBALL,"I2C_WARNING ADDRESS MSB CHANGED");
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jpee_nb &= 0x1A1;
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}
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if (jpee_nb == 0x1A0)
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{
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// JPEE_LOG1(LOG_EVENTS,"I2C_SENT(%02X--start write)",jpee_packet[0]);
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jpee_state = 2;
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jpee_sdat = 0;
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}
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else if (jpee_nb == 0x1A1)
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{
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jpee_state = 4;
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// JPEE_LOG2(LOG_EVENTS,"I2C_SENT(%02X--start read @%04X)",
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// jpee_packet[0],jpee_address);
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// if (!jpee_ad_known)
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// JPEE_LOG0(LOG_ODDBALL,"I2C_WARNING ADDRESS IS UNKNOWN");
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jpee_sdat = 0;
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}
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else
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{
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// JPEE_LOG1(LOG_ODDBALL,"I2C_WARNING ODDBALL FIRST BYTE!(%02X)",jpee_nb & 0xFF);
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jpee_state = 0;
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}
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}
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else
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{
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jpee_state = 2;
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jpee_sdat = 0;
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}
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}
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break;
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case 2:
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if (jpee_nb)
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{
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if (!jpee_pptr)
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{
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jpee_packet[0] = (unsigned char)jpee_nb;
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if (jpee_smallmode)
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jpee_pptr=2;
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else
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jpee_pptr=1;
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}
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else if (jpee_pptr < 70)
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{
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// JPEE_LOG1(LOG_EVENTS,"I2C_SENT(%02X)",jpee_nb & 0xFF);
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jpee_packet[jpee_pptr++] = (unsigned char)jpee_nb;
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jpee_address = (jpee_packet[1] << 8) | jpee_packet[2];
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if (jpee_pptr > 2)
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jpee_ad_known = 1;
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}
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// else
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// JPEE_LOG0(LOG_ODDBALL,"I2C_WARNING OUTPUT_OVERFLOW!");
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}
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jpee_sdat = 1;
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jpee_nb = 1;
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jpee_state=1;
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break;
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case 4:
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if (jpee_mdat && jpee_sdat)
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{
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// JPEE_LOG0(LOG_EVENTS,"I2C_READ_NAK");
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jpee_state=0;
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break;
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}
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jpee_state=3;
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jpee_nb = (myData[jpee_address & jpee_sizemask] << 1) | 1; /* Fall through */
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// JPEE_LOG2(LOG_EVENTS,"I2C_READ(%04X=%02X)",jpee_address,jpee_nb/2);
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case 3:
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jpee_sdat = !!(jpee_nb & 256);
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jpee_nb <<= 1;
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if (!(jpee_nb & 510))
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{
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jpee_state = 4;
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jpee_sdat = 1;
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jpee_address++;
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}
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break;
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default:
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/* Do nothing */
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break;
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}
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// JPEE_LOG2(LOG_EDGES,"I2C_CLOCK (dat=%d/%d)",jpee_mdat,jpee_sdat);
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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int MT24LC256::jpee_timercheck(int mode)
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{
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// TODO - implement a timer emulating the delay in accessing the EEPROM
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// For now, we assume it's always ready
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/*
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The application should define a function jpee_timercheck() which is used to
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evaluate how long the EEPROM is busy. When invoked with an argument of 1,
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the system should start a timer (probably about 5 milliseconds); when invoked
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with an argument of 0, it should return zero if the timer has expired or
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non-zero if it is still running.
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*/
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return 0;
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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MT24LC256::MT24LC256(const MT24LC256& c)
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: myController(c.myController),
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myDataFile(c.myDataFile)
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{
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assert(false);
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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MT24LC256& MT24LC256::operator = (const MT24LC256&)
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{
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assert(false);
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return *this;
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}
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@ -0,0 +1,92 @@
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//============================================================================
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//
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// SSSS tt lll lll
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// SS SS tt ll ll
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// SS tttttt eeee ll ll aaaa
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// SSSS tt ee ee ll ll aa
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// SS tt eeeeee ll ll aaaaa -- "An Atari 2600 VCS Emulator"
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// SS SS tt ee ll ll aa aa
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// SSSS ttt eeeee llll llll aaaaa
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//
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// Copyright (c) 1995-2008 by Bradford W. Mott and the Stella team
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//
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// See the file "license" for information on usage and redistribution of
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// this file, and for a DISCLAIMER OF ALL WARRANTIES.
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//
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// $Id: MT24LC256.hxx,v 1.1 2008-04-13 15:05:58 stephena Exp $
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//============================================================================
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#ifndef MT24LC256_HXX
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#define MT24LC256_HXX
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class Controller;
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#include "bspf.hxx"
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/**
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Emulates a Microchip Technology Inc. 24LC256, a 32KB Serial Electrically
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Erasable PROM accessed using the I2C protocol. Thanks to J. Payson
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(aka Supercat) for the bulk of this code.
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@author Stephen Anthony & J. Payson
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@version $Id: MT24LC256.hxx,v 1.1 2008-04-13 15:05:58 stephena Exp $
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*/
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class MT24LC256
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{
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public:
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/**
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Create a new 24LC256 with its data stored in the given file
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@param filename Data file representing the EEPROM data
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@param controller The controller attached to this device
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*/
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MT24LC256(const string& filename, const Controller* controller);
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/**
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Destructor
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*/
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virtual ~MT24LC256();
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public:
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/** Read boolean data from the SDA line */
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bool readSDA();
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/** Write boolean data to the SDA and SCL lines */
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void writeSDA(bool state);
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void writeSCL(bool state);
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private:
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// I2C access code provided by Supercat
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void jpee_init();
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void jpee_data_start();
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void jpee_data_stop();
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void jpee_clock_fall();
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// int jpee_logproc(char const *st);
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int jpee_timercheck(int mode);
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private:
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// The controller attached to this device
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const Controller* myController;
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// The EEPROM data
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uInt8 myData[32768];
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// The file containing the EEPROM data
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string myDataFile;
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// Required for I2C functionality
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int jpee_mdat, jpee_sdat, jpee_mclk;
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int jpee_sizemask, jpee_pagemask, jpee_smallmode, jpee_logmode;
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int jpee_pptr, jpee_state, jpee_nb;
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unsigned int jpee_address, jpee_ad_known;
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uInt8 jpee_packet[70];
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private:
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// Copy constructor isn't supported by this class so make it private
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MT24LC256(const MT24LC256&);
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// Assignment operator isn't supported by this class so make it private
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MT24LC256& operator = (const MT24LC256&);
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};
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#endif
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@ -39,6 +39,7 @@ MODULE_OBJS := \
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src/emucore/Joystick.o \
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src/emucore/Keyboard.o \
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src/emucore/M6532.o \
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src/emucore/MT24LC256.o \
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src/emucore/MD5.o \
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src/emucore/MediaSrc.o \
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src/emucore/OSystem.o \
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