Add lock command for 28C devices

README.md

@@ -47,6 +47,13 @@ The READ and WRITE command both use XMODEM CRC to complete the file transfers.
 
 The files used for READ and WRITE are simple binary images. This can be created directly by [asm85](http://github.com/TomNisbet/asm85) or can be converted from S-record or Intel HEX using an external utility.
 
+## Troubleshooting
+* If the code doesn't appear to be working, concentrate on the read operations first to verify that the data and address paths are good.
+* Re-check all hardware connections and verify the the control pins are going to the Arduino pins that match the definitions in the code.
+* Verify that the ARDUINO_IS_xxx line in Configure.h matches the Arduino type you are using. Many Arduino boards other than those listed in
+the file may work as well by commenting out all of the ARDUINO_IS_xxx lines.  This will use the slower bit-at-a-time code for that data bus instead of the board-specific code.
+* 28C series EEPROMS, like the 28C256, sometimes ship from the factory with Data Protection enabled.  Use the UNLOCK command to disable this.
+
 ## Further Work
 * Add a new PromDevice class for 27 series EPROMS.
 * Additional error checking in the CmdLine code.

TommyPROM/Configure.h

@@ -1,13 +1,16 @@
-// Uncomment only one of these to use the fast I/O code for the data bus, or
-// comment them all out to use the slower bit-at-a-time code.
+// Uncomment only one of the ARDUINO_IS_ lines to use the fast I/O code for
+// the data bus, or comment them all out to use the slower bit-at-a-time code.
 
 //#define ARDUINO_IS_MICRO
-//#define ARDUINO_IS_UNO
-#define ARDUINO_IS_NANO
+#define ARDUINO_IS_UNO
+//#define ARDUINO_IS_NANO
+
 
 // Comment this out to remove extra debugging commands and code
+
 #define ENABLE_DEBUG_COMMANDS
 
+
 // Uncomment only one of these to choose the PROM device code that will be
 // compiled in.
 
@@ -15,6 +18,7 @@
 //#define PROM_IS_8755A
 
 
+// Don't change anything below this comment unless you are adding support for a new device type.
 #if defined(PROM_IS_28C)
 #include "PromDevice28C.h"
 #elif defined(PROM_IS_8755A)

TommyPROM/PromDevice.h

@@ -22,7 +22,9 @@ class PromDevice
     byte readData(word address) { return readByte(address); }
 
     virtual void begin() = 0;
+    virtual const char * getName() = 0;
     virtual void disableSoftwareWriteProtect() {}
+    virtual void enableSoftwareWriteProtect() {}
 
   protected:
     unsigned int mSize;             // Size of the device, in bytes

TommyPROM/PromDevice28C.cpp

@@ -64,6 +64,23 @@ void PromDevice28C::disableSoftwareWriteProtect()
 }
 
 
+// Write the special three-byte code to turn on Software Data Protection.
+void PromDevice28C::enableSoftwareWriteProtect()
+{
+    disableOutput();
+    disableWrite();
+    enableChip();
+    setDataBusMode(OUTPUT);
+
+    setByte(0xaa, 0x5555);
+    setByte(0x55, 0x2aaa);
+    setByte(0xa0, 0x5555);
+
+    setDataBusMode(INPUT);
+    disableChip();
+}
+
+
 // BEGIN PRIVATE METHODS
 //
 

TommyPROM/PromDevice28C.h

@@ -20,7 +20,9 @@ class PromDevice28C : public PromDevice
   public:
     PromDevice28C(unsigned long size, word blockSize, unsigned maxWriteTime, bool polling);
     void begin();
+    const char * getName() { return "28C series EEPROM"; }
     void disableSoftwareWriteProtect();
+    void enableSoftwareWriteProtect();
 
   protected:
     void setAddress(word address);

TommyPROM/PromDevice8755A.h

@@ -20,6 +20,7 @@ class PromDevice8755A : public PromDevice
   public:
     PromDevice8755A(unsigned long size);
     void begin();
+    const char * getName() { return "Intel 8755A EPROM"; }
 
   protected:
     void setAddress(word address);

TommyPROM/TommyPROM.ino

@@ -71,6 +71,7 @@ enum {
     CMD_DUMP,
     CMD_ERASED,
     CMD_FILL,
+    CMD_LOCK,
     CMD_READ,
     CMD_UNLOCK,
     CMD_WRITE,
@@ -127,6 +128,7 @@ byte parseCommand(char c)
         case 'd':  cmd = CMD_DUMP;      break;
         case 'e':  cmd = CMD_ERASED;    break;
         case 'f':  cmd = CMD_FILL;      break;
+        case 'l':  cmd = CMD_LOCK;      break;
         case 'r':  cmd = CMD_READ;      break;
         case 'u':  cmd = CMD_UNLOCK;    break;
         case 'w':  cmd = CMD_WRITE;     break;
@@ -610,6 +612,11 @@ void loop()
         fillBlock(start, end, val);
         break;
 
+    case CMD_LOCK:
+        Serial.println(F("Writing the lock code to enable Software Write Protect mode."));
+        prom.enableSoftwareWriteProtect();
+        break;
+
     case CMD_READ:
         Serial.println(F("Set the terminal to receive XMODEM CRC"));
         if (xmodem.SendFile(start, uint32_t(end) - start + 1))
@@ -657,14 +664,17 @@ void loop()
         break;
 
     default:
-        Serial.println(F("TommyPROM 1.6\n"));
+        Serial.print(F("TommyPROM 1.7 - "));
+        Serial.println(prom.getName());
+        Serial.println();
         Serial.println(F("Valid commands are:"));
         Serial.println(F("  Cssss eeee    - Compute checksum from device"));
         Serial.println(F("  Dssss eeee    - Dump bytes from device to terminal"));
         Serial.println(F("  Essss eeee    - Check to see if device range is Erased (all FF)"));
         Serial.println(F("  Fssss eeee dd - Fill block on device with fixed value"));
+        Serial.println(F("  L             - Lock (enable) device Software Data Protection"));
         Serial.println(F("  Rssss eeee    - Read from device and save to XMODEM CRC file"));
-        Serial.println(F("  U             - Unlock device Software Data Protection"));
+        Serial.println(F("  U             - Unlock (disable) device Software Data Protection"));
         Serial.println(F("  Wssss         - Write to device from XMODEM CRC file"));
 #ifdef ENABLE_DEBUG_COMMANDS
         Serial.println();