V17B: Read header info even if checksum is corrupt

Some prototypes or hacked roms don't have a valid checksum in the header but still provide useful information like rom size.

Cart_Reader/Cart_Reader.ino

@@ -2,8 +2,8 @@
                   Nintendo Cart Reader for Arduino Mega2560
 
    Author:           sanni
-   Date:             2016-07-11
+   Date:             2016-07-13
-   Version:          V17A
+   Version:          V17B
 
    SD  lib:          https://github.com/greiman/SdFat
    LCD lib:          https://github.com/adafruit/Adafruit_SSD1306
@@ -29,7 +29,7 @@
    Snes9x - SuperFX Sram Fix
 
 **********************************************************************************/
-char ver[5] = "V17A";
+char ver[5] = "V17B";
 
 /******************************************
    Choose Output
@@ -403,7 +403,6 @@ void mainMenu() {
           // get input button
           int b = checkButton();
 
-          // Send some clock pulses to the Eeprom in case it locked up
           // if the cart readers input button is pressed shortly
           if (b == 1) {
             asm volatile ("  jmp 0");

Cart_Reader/NP.ino

@@ -126,7 +126,7 @@ void NPGameMenu() {
       strcpy(romName, gameCode[gameSubMenu + 1]);
 
       // Print info
-      printStartPage();
+      getCartInfo_SNES();
       mode = mode_NPGame;
     }
     else {
@@ -139,7 +139,7 @@ void NPGameMenu() {
       strcpy(romName, gameCode[0]);
 
       // Print info
-      printStartPage();
+      getCartInfo_SNES();
       mode = mode_NPGame;
     }
   }

Cart_Reader/SNS.ino

@@ -34,11 +34,12 @@ const char SnesMenuItem5[] PROGMEM = "Reset";
 const char* const menuOptionsSNES[] PROGMEM = {SnesMenuItem1, SnesMenuItem2, SnesMenuItem3, SnesMenuItem4, SnesMenuItem5};
 
 // Manual config menu items
-const char confMenuItem1[] PROGMEM = "4MB LoRom 256K Sram";
+const char confMenuItem1[] PROGMEM = "Use header info";
-const char confMenuItem2[] PROGMEM = "4MB HiRom 64K Sram";
+const char confMenuItem2[] PROGMEM = "4MB LoRom 256K Sram";
-const char confMenuItem3[] PROGMEM = "6MB ExRom 256K Sram";
+const char confMenuItem3[] PROGMEM = "4MB HiRom 64K Sram";
-const char confMenuItem4[] PROGMEM = "Reset";
+const char confMenuItem4[] PROGMEM = "6MB ExRom 256K Sram";
-const char* const menuOptionsConf[] PROGMEM = {confMenuItem1, confMenuItem2, confMenuItem3, confMenuItem4};
+const char confMenuItem5[] PROGMEM = "Reset";
+const char* const menuOptionsConf[] PROGMEM = {confMenuItem1, confMenuItem2, confMenuItem3, confMenuItem4, confMenuItem5};
 
 // SNES Menu
 void snesMenu() {
@@ -118,37 +119,40 @@ void snesMenu() {
 
 // Menu for manual configuration
 void confMenu() {
-  // create menu with title and 4 options to choose from
+  // create menu with title and 5 options to choose from
   unsigned char subMenu;
   // Copy menuOptions of of progmem
-  convertPgm(menuOptionsConf, 4);
+  convertPgm(menuOptionsConf, 5);
-  subMenu = question_box("Choose mapping", menuOptions, 4, 0);
+  subMenu = question_box("Choose mapping", menuOptions, 5, 0);
 
   // wait for user choice to come back from the question box menu
   switch (subMenu)
   {
     case 0:
+      break;
+
+    case 1:
       romType = LO;
       numBanks = 128;
       sramSize = 256;
       strcpy(romName, "LOROM");
       break;
 
-    case 1:
+    case 2:
       romType = HI;
       numBanks = 64;
       sramSize = 64;
       strcpy(romName, "HIROM");
       break;
 
-    case 2:
+    case 3:
       romType = EX;
       numBanks = 96;
       sramSize = 256;
       strcpy(romName, "EXROM");
       break;
 
-    case 3:
+    case 4:
       // Reset
       asm volatile ("  jmp 0");
       break;
@@ -237,7 +241,7 @@ void setup_Snes() {
   delay(1000);
 
   // Print all the info
-  printStartPage();
+  getCartInfo_SNES();
 }
 
 /******************************************
@@ -303,11 +307,17 @@ byte readBank_SNES(byte myBank, word myAddress) {
 /******************************************
   SNES ROM Functions
 ******************************************/
-void printStartPage() {
+void getCartInfo_SNES() {
+  boolean manualConfig = 0;
+
   // Print start page
-  if (checkcart() == 0) {
+  if (checkcart_SNES() == 0) {
-    display_Clear();
+    // Checksum either corrupt or 0000
+    manualConfig = 1;
+    errorLvl = 1;
     rgb.setColor(255, 0, 0);
+
+    display_Clear();
     println_Msg(F("ERROR"));
     println_Msg(F("Rom header corrupt"));
     println_Msg(F("or missing"));
@@ -318,9 +328,10 @@ void printStartPage() {
     println_Msg(F("or powercycle if SA1"));
     display_Update();
     wait();
-    confMenu();
+    // Wait() clears errors but in this case we still have an error
+    errorLvl = 1;
   }
-  else {
+
   display_Clear();
   print_Msg(F("Rom Name: "));
   println_Msg(romName);
@@ -398,6 +409,10 @@ void printStartPage() {
   println_Msg(F("Press Button..."));
   display_Update();
   wait();
+
+  // Start manual config
+  if (manualConfig == 1) {
+    confMenu();
   }
 }
 
@@ -447,7 +462,7 @@ void checkAltConf() {
 }
 
 // Read header information
-void getCartInfo_SNES() {
+boolean checkcart_SNES() {
   // set control to read
   dataIn();
 
@@ -533,17 +548,18 @@ void getCartInfo_SNES() {
 
   // ROM Version
   romVersion = readBank_SNES(0, 65499);
-}
 
-boolean checkcart() {
+  // Test if checksum is equal to reverse checksum
-  // If cart is present and checksum is equal to reverse checksum
   if (((word(readBank_SNES(0, 65500)) + (word(readBank_SNES(0, 65501)) * 256)) + (word(readBank_SNES(0, 65502)) + (word(readBank_SNES(0, 65503)) * 256))) == 65535 ) {
-    getCartInfo_SNES();
+    if (strcmp("0000", checksumStr) == 0) {
+      return 0;
+    }
+    else {
       return 1;
     }
+  }
   // Either rom checksum is wrong or no cart is inserted
   else {
-    errorLvl = 1;
     return 0;
   }
 }