mirror of
https://github.com/sanni/cartreader.git
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255 lines
6.4 KiB
C++
255 lines
6.4 KiB
C++
//******************************************
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// ATARI LYNX MODULE
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//******************************************
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//
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// For use with SNES-Lynx adapter
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// +----+
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// | 1 |- GND
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// | 2 |- D3
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// | 3 |- D2
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// | 4 |- D4
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// | 5 |- D1
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// | 6 |- D5
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// | 7 |- D0
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// | 8 |- D6
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// | 9 |- D7
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// | 10 |- /OE
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// | 11 |- A1
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// | 12 |- A2
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// | 13 |- A3
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// | 14 |- A6
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// | 15 |- A4
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// | 16 |- A5
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// | 17 |- A0
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// | 18 |- A7
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// | 19 |- A16
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// | 20 |- A17
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// | 21 |- A18
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// | 22 |- A19
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// | 23 |- A15
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// | 24 |- A14
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// | 25 |- A13
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// | 26 |- A12
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// | 27 |- /WE
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// | 28 |- A8
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// | 29 |- A9
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// | 30 |- A10
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// | 31 |- VCC
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// | 32 |- AUDIN
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// | 33 |- VCC
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// | 34 |- SWVCC
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// +----+
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//
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// By @partlyhuman
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// This implementation would not be possible without the invaluable
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// documentation on
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// https://atarilynxvault.com/
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// by Igor (@theatarigamer) of K-Retro Gaming / Atari Lynx Vault
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// and the reference implementation of the Lynx Cart Programmer Pi-Hat
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// https://bitbucket.org/atarilynx/lynx/src/master/
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// by Karri Kaksonen (whitelynx.fi) and Igor as well as countless contributions
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// by the Atari Lynx community
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//
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// Version 1.0
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// Future enhancements
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// 1. EEPROM read/write
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// 2. Homebrew flash cart programming
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//
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#ifdef ENABLE_LYNX
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#pragma region DEFS
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#define LYNX_HEADER_SIZE 64
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#define LYNX_WE 8
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#define LYNX_OE 9
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#define LYNX_AUDIN 46
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#define LYNX_BLOCKADDR 2048UL
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#define LYNX_BLOCKCOUNT 256UL
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// Includes \0
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static const char LYNX[5] = "LYNX";
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// Cart information
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static bool lynxUseAudin;
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static uint16_t lynxBlockSize;
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#pragma region LOWLEVEL
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void setup_LYNX() {
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setVoltage(VOLTS_SET_5V);
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// Address pins output
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// A0-7, A8-A16 (A11 doesn't exist)
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DDRF = 0xff;
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DDRK = 0xff;
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DDRL = 0xff;
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// Data pins input
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DDRC = 0x00;
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// Control pins output
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// CE is tied low, not accessible
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pinMode(LYNX_WE, OUTPUT);
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pinMode(LYNX_OE, OUTPUT);
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pinMode(LYNX_AUDIN, OUTPUT);
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digitalWrite(LYNX_WE, HIGH);
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digitalWrite(LYNX_OE, HIGH);
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digitalWrite(LYNX_AUDIN, HIGH);
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strcpy(romName, LYNX);
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mode = CORE_LYNX;
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}
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static void dataDir_LYNX(byte direction) {
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DDRC = (direction == OUTPUT) ? 0xff : 0x00;
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}
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static uint8_t readByte_LYNX(uint32_t addr, uint8_t audin = 0) {
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digitalWrite(LYNX_OE, HIGH);
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PORTF = addr & 0xff;
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PORTK = (addr >> 8) & 0xff;
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PORTL = ((addr >> 16) & 0b111) | (audin << 3);
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digitalWrite(LYNX_OE, LOW);
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delayMicroseconds(20);
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uint8_t data = PINC;
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digitalWrite(LYNX_OE, HIGH);
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return data;
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}
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#pragma region HIGHLEVEL
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static bool detectCart_LYNX() {
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// Could omit logging to save a few bytes
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display_Clear();
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println_Msg(F("Identifying..."));
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lynxUseAudin = false;
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lynxBlockSize = 0;
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// Somewhat arbitrary, however many bytes would be unlikely to be
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// coincidentally mirrored
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const size_t DETECT_BYTES = 128;
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for (int i = 0; i < DETECT_BYTES; i++) {
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uint8_t b = readByte_LYNX(i);
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// If any differences are detected when AUDIN=1, AUDIN is used to bankswitch
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// meaning we also use the maximum block size
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// (1024kb cart / 256 blocks = 4kb block bank switched between lower/upper 2kb blocks)
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if (b != readByte_LYNX(i, 1)) {
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lynxUseAudin = true;
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lynxBlockSize = 2048;
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break;
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}
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// Identify mirroring of largest stride
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// Valid cart sizes of 128kb, 256kb, 512kb / 256 blocks = block sizes of 512b, 1024b, 2048b
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if (b != readByte_LYNX(i + 1024)) {
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lynxBlockSize = max(lynxBlockSize, 2048);
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} else if (b != readByte_LYNX(i + 512)) {
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lynxBlockSize = max(lynxBlockSize, 1024);
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} else if (b != readByte_LYNX(i + 256)) {
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lynxBlockSize = max(lynxBlockSize, 512);
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}
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}
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if (lynxBlockSize == 0) {
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print_STR(error_STR, false);
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display_Update();
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wait();
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resetArduino();
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}
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print_Msg(F("AUDIN="));
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print_Msg(lynxUseAudin);
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print_Msg(F(" BLOCK="));
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println_Msg(lynxBlockSize);
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display_Update();
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}
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static void writeHeader_LYNX() {
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char header[LYNX_HEADER_SIZE] = {};
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// Magic number
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strcpy(header, LYNX);
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// Cart name (dummy)
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strcpy(header + 10, LYNX);
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// Manufacturer (dummy)
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strcpy(header + 42, LYNX);
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// Version
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header[8] = 1;
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// Bank 0 page size
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header[4] = lynxBlockSize & 0xff;
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// Bank 1 page size
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header[5] = (lynxBlockSize >> 8) & 0xff;
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// AUDIN used
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header[59] = lynxUseAudin;
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// TODO detect EEPROM?
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// header[60] = lynxUseEeprom;
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myFile.write(header, LYNX_HEADER_SIZE);
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}
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// Saves memory by using existing sd buffer instead of a second block-sized buffer (which could be up to 2KB)
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// Minimum block size is 512b, size of sdBuffer is 512b, all block sizes multiples of 512b,
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// so we shouldn't need to check for leftovers...
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static inline void ringBufferWrite_LYNX(uint32_t blocki, uint8_t byte) {
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sdBuffer[blocki % 512] = byte;
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if ((blocki + 1) % 512 == 0) {
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myFile.write(sdBuffer, 512);
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}
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}
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static void readROM_LYNX() {
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dataDir_LYNX(INPUT);
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// The upper part of the address is used as a block address
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// There are always 256 blocks, but the size of the block can vary
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// So outer loop always steps through block addresses
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uint32_t i;
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const uint32_t upto = LYNX_BLOCKCOUNT * LYNX_BLOCKADDR;
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for (uint32_t blockAddr = 0; blockAddr < upto; blockAddr += LYNX_BLOCKADDR) {
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draw_progressbar(blockAddr, upto);
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blinkLED();
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if (lynxUseAudin) {
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// AUDIN bank switching uses a 4kb block split to 2 banks
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for (i = 0; i < lynxBlockSize / 2; i++) {
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ringBufferWrite_LYNX(i, readByte_LYNX(blockAddr + i, 0));
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}
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for (; i < lynxBlockSize; i++) {
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ringBufferWrite_LYNX(i, readByte_LYNX(blockAddr + i - (lynxBlockSize / 2), 1));
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}
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} else {
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for (i = 0; i < lynxBlockSize; i++) {
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ringBufferWrite_LYNX(i, readByte_LYNX(i + blockAddr));
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}
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}
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}
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draw_progressbar(upto, upto);
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}
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#pragma region MENU
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static const char* const menuOptionsLYNX[] PROGMEM = {FSTRING_READ_ROM, FSTRING_RESET};
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void lynxMenu() {
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size_t menuCount = sizeof(menuOptionsLYNX) / sizeof(menuOptionsLYNX[0]);
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convertPgm(menuOptionsLYNX, menuCount);
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uint8_t mainMenu = question_box(F("LYNX MENU"), menuOptions, menuCount, 0);
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display_Clear();
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display_Update();
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switch (mainMenu) {
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case 0:
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sd.chdir("/");
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createFolderAndOpenFile(LYNX, "ROM", romName, "lnx");
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detectCart_LYNX();
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writeHeader_LYNX();
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readROM_LYNX();
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myFile.close();
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sd.chdir("/");
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compareCRC("lynx.txt", 0, true, LYNX_HEADER_SIZE);
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print_STR(done_STR, true);
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display_Update();
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wait();
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break;
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}
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}
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#endif |