Speed up setAddr code to meet SDP timing restrictions

HardwareVerify/Configure.h

@@ -1,9 +1,4 @@
-// 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
-
 
 #include "PromDevice28C.h"

HardwareVerify/HardwareVerify.ino

@@ -145,19 +145,20 @@ void setup()
     Serial.begin(115200);
 }
 
-
-
-word start = 0;
-word end = 0xff;
-byte val = 0xff;
-
 void loop()
+{
+    commandLoop();
+}
+
+static void commandLoop()
 {
     byte b;
     word w;
-    bool error = false;
     char line[20];
     uint32_t numBytes;
+    unsigned long timeStart;
+    unsigned long timeEnd;
+    bool cmdError = false;
 
     Serial.print("\n#");
     Serial.flush();
@@ -167,12 +168,6 @@ void loop()
         c |= 0x20;
     }
 
-    /*
-    * Note that the comamnds here allow for direct writing of the 28C control lines with some exceptions to
-    * protect the chip and the host arduino:
-    *   1) When the O command is used to enable chip output, the arduino data bus us set to INPUT
-    *   2) When the D command is used to write data from the arduino, the chip output is disabled
-    *   3) The R command sets to output enable (OE) on the chip (but not the chip enable (CE)) */
     switch (c)
     {
     case 'a':
@@ -182,8 +177,9 @@ void loop()
             prom.setAddress(w);
         }
         else
-            error = true;
+            cmdError = true;
         break;
+
     case 'd':
         if (hexDigit(line[1]) <= 15)
         {
@@ -193,12 +189,18 @@ void loop()
             prom.writeDataBus(b);
         }
         else
-            error = true;
+            cmdError = true;
         break;
+
     case 'c':
     case 'o':
     case 'w':
-        if ((line[1] == 'd') || (line[1] == 'e')) {
+        if ((line[1] != 'd') && (line[1] != 'e'))
+        {
+            cmdError = true;
+        }
+        else
+        {
             bool enable = line[1] == 'e';
             if (c == 'c')
                 if (enable) prom.enableChip(); else prom.disableChip();
@@ -214,10 +216,6 @@ void loop()
                 else prom.disableOutput();
             }
         }
-        else
-        {
-            error = true;
-        }
         break;
 
     case 'r':
@@ -236,19 +234,19 @@ void loop()
 
     case 'u':
         Serial.println(F("Writing the unlock code to disable Software Write Protect mode."));
-        unsigned long timeStart = micros();
+        timeStart = micros();
         prom.disableSoftwareWriteProtect();
-        unsigned long timeEnd = micros();
+        timeEnd = micros();
         Serial.print("Unlock command time in uSec=");
         Serial.println(timeEnd - timeStart);
         break;
 
     default:
-        error = true;
+        cmdError = true;
         break;
     }
 
-    if (error) {
+    if (cmdError) {
         Serial.print(F("Hardware Verifier - "));
         Serial.println(prom.getName());
         Serial.println();

HardwareVerify/PromAddressDriver.cpp

@@ -33,10 +33,10 @@ void PromAddressDriver::setAddress(word address)
 
     if (hi != lastHi)
     {
-        setAddressRegister(ADDR_CLK_HI, hi);
+        setAddressRegisterDirect(ADDR_CLK_HI, hi);
         lastHi = hi;
     }
-    setAddressRegister(ADDR_CLK_LO, lo);
+    setAddressRegisterDirect(ADDR_CLK_LO, lo);
 }
 
 
@@ -67,4 +67,38 @@ void PromAddressDriver::setAddressRegister(uint8_t clkPin, byte addr)
     }
 }
 
+// Shift an 8-bit value into one of the address shift registers.  Note that
+// the data pins are tied together, selecting the high or low address register
+// is a matter of using the correct clock pin to shift the data in.
+void PromAddressDriver::setAddressRegisterDirect(uint8_t clkPin, byte addr)
+{
+    byte mask = 0;
+    if (clkPin == A3)
+        mask = 0x08;
+    else if (clkPin == A4)
+        mask = 0x10;
+
+    // Make sure the clock is low to start.
+    PORTC &= ~mask;
+
+    // Shift 8 bits in, starting with the MSB.
+    for (int ix = 0; (ix < 8); ix++)
+    {
+        // Set the data bit
+        if (addr & 0x80)
+        {
+            PORTC |= 0x20;
+        }
+        else
+        {
+            PORTC &= 0xdf;
+        }
+
+        // Toggle the clock high then low
+        PORTC |= mask;
+        delayMicroseconds(3);
+        PORTC &= ~mask;
+        addr <<= 1;
+    }
+}
 

HardwareVerify/PromAddressDriver.h

@@ -10,6 +10,7 @@ class PromAddressDriver {
 
   private:
     static void setAddressRegister(uint8_t clkPin, byte addr);
+    static void setAddressRegisterDirect(uint8_t clkPin, byte addr);
 };
 
 

HardwareVerify/PromDevice.cpp

@@ -75,7 +75,6 @@ bool PromDevice::writeData(byte data[], word len, word address)
 // on pins D2..D9.
 void PromDevice::setDataBusMode(uint8_t mode)
 {
-#if defined(ARDUINO_IS_UNO) || defined(ARDUINO_IS_NANO)
     // On the Uno and Nano, D2..D9 maps to the upper 6 bits of port D and the
     // lower 2 bits of port B.
     if (mode == OUTPUT)
@@ -88,26 +87,6 @@ void PromDevice::setDataBusMode(uint8_t mode)
         DDRB &= 0xfc;
         DDRD &= 0x03;
     }
-#elif defined(ARDUINO_IS_MICRO)
-    // On the Micro, D2..D9 maps to the upper 7 bits of port B and the
-    // lower bit of port D.
-    if (mode == OUTPUT)
-    {
-        DDRB |= 0xfe;
-        DDRD |= 0x01;
-    }
-        else
-    {
-        DDRB &= 0x01;
-        DDRD &= 0xfe;
-    }
-#else
-    byte bit = 0x01;
-    for (int pin = 2; (pin <= 9); pin++) {
-        pinMode(pin, mode);
-        bit <<= 1;
-    }
-#endif
 }
 
 
@@ -115,21 +94,7 @@ void PromDevice::setDataBusMode(uint8_t mode)
 // before calling this or no useful data will be returned.
 byte PromDevice::readDataBus()
 {
-#if defined(ARDUINO_IS_UNO) || defined(ARDUINO_IS_NANO)
     return (PINB << 6) | (PIND >> 2);
-#elif defined(ARDUINO_IS_MICRO)
-    return (PINB & 0xfe) | (PIND & 0x01);
-#else
-    byte data = 0;
-    byte bit = 0x01;
-    for (int pin = 2; (pin <= 9); pin++) {
-        if (digitalRead(pin) == HIGH) {
-            data |= bit;
-        }
-        bit <<= 1;
-    }
-    return data;
-#endif
 }
 
 
@@ -137,19 +102,8 @@ byte PromDevice::readDataBus()
 // before calling this or no data will be written.
 void PromDevice::writeDataBus(byte data)
 {
-#if defined(ARDUINO_IS_UNO) || defined(ARDUINO_IS_NANO)
      PORTB = (PORTB & 0xfc) | (data >> 6);
      PORTD = (PORTD & 0x03) | (data << 2);
-#elif defined(ARDUINO_IS_MICRO)
-    PORTB = (PORTB & 0x01) | (data & 0xfe);
-    PORTD = (PORTD & 0xfe) | (data & 0x01);
-#else
-    byte bit = 0x01;
-    for (int pin = 2; (pin <= 9); pin++) {
-        digitalWrite(pin, (data & bit) ? HIGH : LOW);
-        bit <<= 1;
-    }
-#endif
 }
 
 

HardwareVerify/PromDevice28C.cpp

@@ -204,8 +204,8 @@ void PromDevice28C::setByte(byte value, word address)
     enableChip();
     enableWrite();
     delayMicroseconds(1);
-    disableChip();
     disableWrite();
+    disableChip();
 }
 
 

HardwareVerify/README.md

@@ -9,6 +9,7 @@ Note that the comamnds allow for direct writing of the 28C control lines with so
 * When the O command is used to enable chip output, the arduino data bus is set to INPUT
 * When the D command is used to write data from the arduino, the chip output is disabled
 * The R command sets the output enable (OE) on the chip, but not the chip enable (CE)
+* The L and U commands reset CE, OE, and WE back to disabled on completion and change the data and address
 
 The session below shows how a write fails to a locked chip and then succeeds once the chip is unlocked.