/* Interfacing the Arduino Duemilanove to Am29F010 devices.  Copyright (C) 2015 Paul Boddie <paul@boddie.org.uk>  This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.  You should have received a copy of the GNU General Public License along with this program.  If not, see <http://www.gnu.org/licenses/>. */  const int CE = A5, OE = A4, WE = A3, A16 = A2,           CS1 = 2, CS2 = 3,           DQ0 = 7, DQ1 = 6, DQ2 = 5, DQ3 = 4,           DQ4 = 8, DQ5 = 9, DQ6 = 10, DQ7 = 11;  const int BUFSIZE = 8; char inbuffer[BUFSIZE]; int nread = 0;  const char ERASE[][8] = {     "W5555AA", "W2AAA55", "W555580", "W5555AA", "W2AAA55"     }; const char PROGRAM[][8] = {     "W5555AA", "W2AAA55", "W5555A0"     };  int fromHex(char c) {     if ((c >= 48) && (c <= 57))         return c - 48;     if ((c >= 65) && (c <= 70))         return c - 65 + 10;     if ((c >= 97) && (c <= 102))         return c - 97 + 10;     return 0; }  void setDataOut() {     pinMode(DQ0, OUTPUT);     pinMode(DQ1, OUTPUT);     pinMode(DQ2, OUTPUT);     pinMode(DQ3, OUTPUT);     pinMode(DQ4, OUTPUT);     pinMode(DQ5, OUTPUT);     pinMode(DQ6, OUTPUT);     pinMode(DQ7, OUTPUT); }  void setDataIn() {     pinMode(DQ0, INPUT);     pinMode(DQ1, INPUT);     pinMode(DQ2, INPUT);     pinMode(DQ3, INPUT);     pinMode(DQ4, INPUT);     pinMode(DQ5, INPUT);     pinMode(DQ6, INPUT);     pinMode(DQ7, INPUT); }  int sampleData() {     int i = DQ7;     int data = 0;      while (1)     {         data += digitalRead(i);         if (i == DQ0)             break;         i--;         data <<= 1;     }      return data; }  int readData() {     int data = 0;      setDataIn();     delay(1);     data = sampleData();     setDataOut();     return data; }  void writeData(int data) {     int i = DQ0;      while (1)     {         digitalWrite(i, data % 2);         if (i == DQ7)             break;         i++;         data >>= 1;     } }  void setAddress(int high, int low) {     /* The top bit is sent directly. */      if (high & 0x100)         digitalWrite(A16, HIGH);     else         digitalWrite(A16, LOW);      /* The lower 16 bits are sent via the latches. */      writeData(high);     delayMicroseconds(1);     digitalWrite(CS2, HIGH);     delayMicroseconds(1);     digitalWrite(CS2, LOW);     writeData(low);     delayMicroseconds(1);     digitalWrite(CS1, HIGH);     delayMicroseconds(1);     digitalWrite(CS1, LOW); }  int readOp(int high, int low) {     int data;      digitalWrite(CE, LOW);     setAddress(high, low);     delay(1);     digitalWrite(OE, LOW);     data = readData();     delay(1);     digitalWrite(OE, HIGH);     digitalWrite(CE, HIGH);      return data; }  void writeOp(int high, int low, int data) {     digitalWrite(CE, LOW);     setAddress(high, low);     delay(1);     digitalWrite(WE, LOW);     writeData(data);     delay(1);     digitalWrite(WE, HIGH);     digitalWrite(CE, HIGH); }  int readCommand(const char buffer[]) {     int high, low, i;      if (nread > 5)     {         high = fromHex(buffer[1]) << 8;         i = 2;     }     else         i = 1;      high |= (fromHex(buffer[i]) << 4) + (fromHex(buffer[i+1]));     low = (fromHex(buffer[i+2]) << 4) + (fromHex(buffer[i+3]));      return readOp(high, low); }  bool writeCommand(const char buffer[]) {     int high, low, data, i;      if (nread > 7)     {         high = fromHex(buffer[1]) << 8;         i = 2;     }     else         i = 1;      high |= (fromHex(buffer[i]) << 4) + (fromHex(buffer[i+1]));     low = (fromHex(buffer[i+2]) << 4) + (fromHex(buffer[i+3]));     data = (fromHex(buffer[i+4]) << 4) + (fromHex(buffer[i+5]));      writeOp(high, low, data);      return true; }  bool waitForCompletion(int high, int low, int written) {     int data, then = millis();      setDataIn();     digitalWrite(CE, LOW);     digitalWrite(OE, LOW);      do     {         delay(10);         data = sampleData();     } while (         ((data & 0x80) != (written & 0x80)) &&         ((data & 0x20) == 0) &&         (millis() - then < 2000)         );      digitalWrite(OE, HIGH);     digitalWrite(CE, HIGH);     setDataOut();     delay(10);     return readOp(high, low) == written; }  bool chipErase() {     for (int i = 0; i < 5; i++)     {         writeCommand(ERASE[i]);     }     writeOp(0x55, 0x55, 0x30);     return waitForCompletion(0, 0, 0xff); }  bool sectorErase(const char buffer[]) {     int high;      // 3-bit number shifted to A16...A14 with A16 discarded.     // Thus, only sectors from 0 to 3 are supported.      high = (fromHex(buffer[1]) << 6) & 0xff;      for (int i = 0; i < 5; i++)     {         writeCommand(ERASE[i]);     }     writeOp(high, 0, 0x30);      // Result of erase if 0xff written to all locations.      return waitForCompletion(high, 0, 0xff); }  bool program(const char buffer[]) {     int high, low, data;      high = (fromHex(buffer[1]) << 4) + (fromHex(buffer[2]));     low = (fromHex(buffer[3]) << 4) + (fromHex(buffer[4]));     data = (fromHex(buffer[5]) << 4) + (fromHex(buffer[6]));      for (int i = 0; i < 3; i++)     {         writeCommand(PROGRAM[i]);     }     writeOp(high, low, data);      return waitForCompletion(high, low, data); }  void setup() {     Serial.begin(115200);     pinMode(CE, OUTPUT);     pinMode(OE, OUTPUT);     pinMode(WE, OUTPUT);     pinMode(A16, OUTPUT);     pinMode(CS1, OUTPUT);     pinMode(CS2, OUTPUT);     setDataOut();      // Initial state for the flash device.      digitalWrite(CE, HIGH);     digitalWrite(OE, HIGH);     digitalWrite(WE, HIGH);     digitalWrite(A16, LOW);      // Initial state for the latches.      digitalWrite(CS1, LOW);     digitalWrite(CS2, LOW);      // Interface loop.      Serial.println("?"); }  void loop() {     if (nread += Serial.readBytesUntil('\n', inbuffer + nread, BUFSIZE - nread))     {         switch (inbuffer[0])         {             case 'R':             if (nread >= 5)             {                 Serial.println(readCommand(inbuffer), HEX);                 nread = 0;             }             break;              case 'W':             if (nread >= 7)             {                 if (writeCommand(inbuffer))                     Serial.println("W");                 else                     Serial.println("C");                 nread = 0;             }             break;              case 'E':             if (chipErase())                 Serial.println("E");             else                 Serial.println("C");             nread = 0;             break;              case 'S':             if (nread >= 2)             {                 if (sectorErase(inbuffer))                     Serial.println("S");                 else                     Serial.println("C");                 nread = 0;             }             break;              case 'P':             if (nread >= 7)             {                 if (program(inbuffer))                     Serial.println("P");                 else                     Serial.println("C");                 nread = 0;             }             break;              default:             Serial.println(inbuffer[0]);             nread = 0;             break;         }          Serial.flush();     } }  extern "C" void __cxa_pure_virtual(void) {     while(1); }  // tabstop=4 expandtab shiftwidth=4