V27A: Add Mega Drive SRAM read/write

Only tested with the game STRIKER. There are probably multiple types of SRAM games so not all will work yet.

Cart_Reader/Cart_Reader.ino

@@ -2,8 +2,8 @@
                     Cartridge Reader for Arduino Mega2560
 
    Author:           sanni
-   Date:             2017-06-26
+   Date:             2017-06-27
-   Version:          V27
+   Version:          V27A
 
    SD  lib:         https://github.com/greiman/SdFat
    LCD lib:         https://github.com/adafruit/Adafruit_SSD1306
@@ -34,7 +34,7 @@
    YamaArashi - GBA flashrom bank switch command
 
 **********************************************************************************/
-char ver[5] = "V27";
+char ver[5] = "V27A";
 
 /******************************************
    Define Output
@@ -192,6 +192,7 @@ char cartID[5];
 unsigned long cartSize;
 char flashid[5];
 unsigned long fileSize;
+unsigned long sramBase;
 
 // Variable to count errors
 unsigned long writeErrors;

Cart_Reader/MD.ino

@@ -2,6 +2,11 @@
 // SEGA MEGA DRIVE
 //******************************************
 
+/******************************************
+   Variables
+ *****************************************/
+unsigned long sramEnd;
+
 /******************************************
    Menu
  *****************************************/
@@ -18,7 +23,7 @@ void mdMenu() {
   unsigned char mainMenu;
   // Copy menuOptions out of progmem
   convertPgm(menuOptionsMD, 5);
-  mainMenu = question_box("MEGA DRIVE Reader", menuOptions, 1, 0);
+  mainMenu = question_box("MEGA DRIVE Reader", menuOptions, 3, 0);
 
   // wait for user choice to come back from the question box menu
   switch (mainMenu)
@@ -31,45 +36,50 @@ void mdMenu() {
       //compare_checksum_MD();
       break;
 
-      /*case 1:
+    case 1:
+      display_Clear();
+      // Does cartridge have SRAM
+      if ((saveType == 1) || (saveType == 2)) {
+        // Change working dir to root
+        sd.chdir("/");
+        println_Msg(F("Reading Sram..."));
+        display_Update();
+        readSram_MD();
+      }
+      else {
+        print_Error(F("Cart has no Sram"), false);
+      }
+      break;
+
+    case 2:
+      display_Clear();
+      // Does cartridge have SRAM
+      if ((saveType == 1) || (saveType == 2)) {
+        // Change working dir to root
+        sd.chdir("/");
+        // Launch file browser
+        fileBrowser("Select srm file");
         display_Clear();
-        // Does cartridge have SRAM
+
-        if () {
+        writeSram_MD();
-          // Change working dir to root
+        writeErrors = verifySram_MD();
-          sd.chdir("/");
+        if (writeErrors == 0) {
-          readSRAM_MD();
+          println_Msg(F("Sram verified OK"));
+          display_Update();
         }
         else {
-          print_Error(F("Cart has no Sram"), false);
+          print_Msg(F("Error: "));
+          print_Msg(writeErrors);
+          println_Msg(F(" bytes "));
+          print_Error(F("did not verify."), false);
         }
-        break;
+      }
+      else {
+        print_Error(F("Cart has no Sram"), false);
+      }
+      break;
 
-        case 2:
+      /*case 3:
-        display_Clear();
-        // Does cartridge have SRAM
-        if () {
-          // Change working dir to root
-          sd.chdir("/");
-          writeSRAM_MD();
-          unsigned long wrErrors;
-          wrErrors = verifySRAM_MD();
-          if (wrErrors == 0) {
-            println_Msg(F("Verified OK"));
-            display_Update();
-          }
-          else {
-            print_Msg(F("Error: "));
-            print_Msg(wrErrors);
-            println_Msg(F(" bytes "));
-            print_Error(F("did not verify."), false);
-          }
-        }
-        else {
-          print_Error(F("Cart has no Sram"), false);
-        }
-        break;
-
-        case 3:
         // Change working dir to root
         sd.chdir("/");
         writeFlash_MD();
@@ -134,7 +144,7 @@ void writeWord_MD(unsigned long myAddress, word myData) {
 
   // Arduino running at 16Mhz -> one nop = 62.5ns
   // Wait till output is stable
-  __asm__("nop\n\t");
+  __asm__("nop\n\t""nop\n\t");
 
   // Switch WR(PH5) to LOW
   PORTH &= ~(1 << 5);
@@ -155,7 +165,7 @@ word readWord_MD(unsigned long myAddress) {
   PORTL = (myAddress >> 16) & 0xFF;
 
   // Arduino running at 16Mhz -> one nop = 62.5ns
-  __asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t""nop\n\t");
+  __asm__("nop\n\t""nop\n\t");
 
   // Setting OE(PH6) LOW
   PORTH &= ~(1 << 6);
@@ -188,8 +198,40 @@ void dataIn_MD() {
   MEGA DRIVE functions
 *****************************************/
 void getCartInfo_MD() {
+  // Set control
+  dataIn_MD();
+
   cartSize = ((long(readWord_MD(0xD2)) << 16) | readWord_MD(0xD3)) + 1;
-  sramSize = ((long(readWord_MD(0xDC)) << 16) | readWord_MD(0xDD)) - ((long(readWord_MD(0xDA)) << 16) | readWord_MD(0xDB)) + 2;
+
+  // Check if cart has sram
+  if ((readWord_MD(0xD8) == 0x5241) && (readWord_MD(0xD9) == 0xF820)) {
+    // Get sram start and end
+    sramBase = ((long(readWord_MD(0xDA)) << 16) | readWord_MD(0xDB));
+    sramEnd = ((long(readWord_MD(0xDC)) << 16) | readWord_MD(0xDD));
+
+    // Check alignment of sram
+    if (sramBase == 0x200001) {
+      // low byte
+      saveType = 1;
+      sramSize = (sramEnd - sramBase + 2) / 2;
+      // Right shift sram base address so [A21] is set to high 0x200000 = 0b001[0]00000000000000000000
+      sramBase = sramBase >> 1;
+    }
+    else if (sramBase == 0x200000) {
+      // high byte
+      saveType = 2;
+      sramSize = (sramEnd - sramBase + 1) / 2;
+      // Right shift sram base address so [A21] is set to high 0x200000 = 0b001[0]00000000000000000000
+      sramBase = sramBase / 2;
+    }
+    else
+      print_Error(F("Unknown Sram Base"), true);
+  }
+  else {
+    // Either no save or eeprom save
+    saveType = 0;
+    sramSize = 0;
+  }
 
   // Get name
   for (byte c = 0; c < 48; c += 2) {
@@ -219,12 +261,16 @@ void getCartInfo_MD() {
   print_Msg(cartSize / 1024 / 1024);
   println_Msg(F("MB"));
   print_Msg(F("Sram: "));
-  print_Msg(sramSize / 1024);
+  if (sramSize > 0) {
-  println_Msg(F("KB"));
+    print_Msg(sramSize / 1024);
+    println_Msg(F("KB"));
+  }
+  else
+    println_Msg(F("None"));
+  println_Msg(F(" "));
 
   // Wait for user input
   if (enable_OLED) {
-    println_Msg(F(" "));
     println_Msg(F("Press Button..."));
     display_Update();
     wait();
@@ -233,6 +279,9 @@ void getCartInfo_MD() {
 
 // Read rom and save to the SD card
 void readROM_MD() {
+  // Set control
+  dataIn_MD();
+
   // Get name, add extension and convert to char array for sd lib
   strcpy(fileName, romName);
   strcat(fileName, ".MD");
@@ -280,3 +329,126 @@ void readROM_MD() {
   myFile.close();
 }
 
+/******************************************
+  SRAM functions
+*****************************************/
+// Write sram to cartridge
+void writeSram_MD() {
+  dataOut_MD();
+
+  // Create filepath
+  sprintf(filePath, "%s/%s", filePath, fileName);
+  println_Msg(F("Writing..."));
+  println_Msg(filePath);
+  display_Update();
+
+  // Open file on sd card
+  if (myFile.open(filePath, O_READ)) {
+    // Write to the lower byte
+    if (saveType == 1) {
+      for (unsigned long currByte = sramBase; currByte < sramBase + sramSize; currByte++) {
+        writeWord_MD(currByte, (myFile.read() & 0xFF));
+      }
+    }
+    // Write to the upper byte
+    else if (saveType == 2) {
+      for (unsigned long currByte = sramBase; currByte < sramBase + sramSize; currByte++) {
+        writeWord_MD(currByte, ((myFile.read() << 8 ) & 0xFF));
+      }
+    }
+    else
+      print_Error(F("Unknown save type"), false);
+
+    // Close the file:
+    myFile.close();
+    println_Msg(F("Done"));
+    display_Update();
+  }
+  else {
+    print_Error(F("SD Error"), true);
+  }
+  dataIn_MD();
+}
+
+// Read sram and save to the SD card
+void readSram_MD() {
+  dataIn_MD();
+
+  // Get name, add extension and convert to char array for sd lib
+  strcpy(fileName, romName);
+  strcat(fileName, ".srm");
+
+  // create a new folder for the save file
+  EEPROM_readAnything(10, foldern);
+  sprintf(folder, "MD/SAVE/%s/%d", romName, foldern);
+  sd.mkdir(folder, true);
+  sd.chdir(folder);
+
+  // write new folder number back to eeprom
+  foldern = foldern + 1;
+  EEPROM_writeAnything(10, foldern);
+
+  // Open file on sd card
+  if (!myFile.open(fileName, O_RDWR | O_CREAT)) {
+    print_Error(F("SD Error"), true);
+  }
+
+  for (unsigned long currBuffer = sramBase; currBuffer < sramBase + sramSize; currBuffer += 512) {
+    for (int currWord = 0; currWord < 512; currWord++) {
+      word myWord = readWord_MD(currBuffer + currWord);
+
+      if (saveType == 2) {
+        // Only use the upper byte
+        sdBuffer[currWord] = (( myWord >> 8 ) & 0xFF);
+      }
+      else if (saveType == 1) {
+        // Only use the lower byte
+        sdBuffer[currWord] = (myWord & 0xFF);
+      }
+    }
+    myFile.write(sdBuffer, 512);
+  }
+  // Close the file:
+  myFile.close();
+  print_Msg(F("Saved to "));
+  print_Msg(folder);
+  println_Msg(F("/"));
+  display_Update();
+}
+
+unsigned long verifySram_MD() {
+  dataIn_MD();
+  writeErrors = 0;
+
+  // Open file on sd card
+  if (myFile.open(filePath, O_READ)) {
+    for (unsigned long currBuffer = sramBase; currBuffer < sramBase + sramSize; currBuffer += 512) {
+      for (int currWord = 0; currWord < 512; currWord++) {
+        word myWord = readWord_MD(currBuffer + currWord);
+
+        if (saveType == 2) {
+          // Only use the upper byte
+          sdBuffer[currWord] = (( myWord >> 8 ) & 0xFF);
+        }
+        else if (saveType == 1) {
+          // Only use the lower byte
+          sdBuffer[currWord] = (myWord & 0xFF);
+        }
+      }
+      // Check sdBuffer content against file on sd card
+      for (int i = 0; i < 512; i++) {
+        if (myFile.read() != sdBuffer[i]) {
+          writeErrors++;
+        }
+      }
+    }
+
+    // Close the file:
+    myFile.close();
+  }
+  else {
+    print_Error(F("SD Error"), true);
+  }
+  // Return 0 if verified ok, or number of errors
+  return writeErrors;
+}

Cart_Reader/N64.ino

@@ -37,7 +37,6 @@ String lastbutton = "N/A";
 
 // Rom base address
 unsigned long romBase = 0x10000000;
-unsigned long sramBase = 0x08000000;
 
 // Flashram type
 byte flashramType = 1;
@@ -277,6 +276,9 @@ void setup_N64_Cart() {
   // Activate Internal Pullup Resistors
   //PORTH |= (1 << 4);
 
+  // Set sram base address
+  sramBase = 0x08000000;
+
   // Wait until all is stable
   delay(300);