#define tASD 1
#define tASL 1
#define tASED 1
#define tCS 1
#define tAHL 1
#define tASED 1
#define PWEH 1
#define tDDR  1
#define tDHR  1

#define FRQ_DISABLED  0
#define FRQ_256HZ     1
#define FRQ_128HZ     1

#define AS  13
#define DS  4
#define RW  3
//#define CS  0
#define RESET 2 

char buspins [] = {5,6,7,8,9,10,11,12};
int pincount = sizeof(buspins);
byte curstate = 0xFF;
byte newstate = curstate;
int BusMode = 0xFF;

void switchBusMode(int mode) {
  if(BusMode!=mode) {
    if(mode == OUTPUT) {
      DDRD = 0xFF;
    } else {
      DDRD = 0;
    }
    BusMode=mode;
  }
}

void setBusData(byte data) {
  PORTD = data;
}

byte getBusData() {
  byte result = PIND;
  return result;
}

void resetSignals() {
  //Init state: AS:0; DS:0; R/W|: 0; CS|: 1; AD0-7: 0
  //digitalWrite(CS, HIGH);
  digitalWrite(AS, LOW);
  digitalWrite(DS, HIGH);
  digitalWrite(RW, HIGH);
  setBusData(0);
  switchBusMode(OUTPUT);
  delay(1);
}

void initControlSignals() {
  digitalWrite(RESET, LOW);
  resetSignals();

  pinMode(RESET, OUTPUT);
  //pinMode(CS, OUTPUT);
  pinMode(AS, OUTPUT);
  pinMode(DS, OUTPUT);
  pinMode(RW, OUTPUT);
  delay(300);
  digitalWrite(RESET, HIGH);
}

void startDevice() {

}

char hexToChar(byte *ptr, int size) {
  char result = 0;
  for(int i=0; i<size; i++) {
    result = result << 4;
    if(ptr[i]>='A' && ptr[i]<='F') {
      result = result + ptr[i] - 'A'+10;
    } else if(ptr[i]>='a' && ptr[i]<='f') {
      result = result + ptr[i] - 'a'+10;
    } else if(ptr[i]>='0' && ptr[i]<='9') {
      result = result + ptr[i] - '0';
    }
  }
  return result;
}

byte readInput(byte old) {
  byte buf[64];
  int count = Serial.available();
  byte result = old;
  if(count) {
    int toRead = min(64,count);
    Serial.readBytes(buf,toRead);
    result = hexToChar(buf, toRead-1);
  }  
  return result;
}

void testOutput() {
  switchBusMode(OUTPUT);
  if(newstate != curstate) {
    setBusData(newstate);
    curstate = newstate;
  }
  newstate = readInput(curstate);
}

void testInput() {
  switchBusMode(INPUT);
  Serial.println(getBusData(),HEX);
}

void writeData(byte addr, byte data) {

}

byte readData(byte addr) {
  byte result = 0;
  digitalWrite(RW, HIGH);
  digitalWrite(DS, HIGH);
  delay(tASD);
  digitalWrite(AS, HIGH);
  setBusData(addr);         //AS0-7 set addres value
  delay(tASL);  
  digitalWrite(AS, LOW);   //AS > 0 after PWASH 60ns and tASL 30ns
  delay(tAHL);
  switchBusMode(INPUT);
  delay(tASED);
  digitalWrite(DS, LOW);
  delay(PWEH);
  result = getBusData();
  delay(tDDR);
  digitalWrite(DS, HIGH);
  delay(tDHR);

  /*restor bus signals to default*/
  resetSignals();
  return result;
}


void testDSread() {
  byte addr = readInput(0);
  Serial.print("Reading from:");
  Serial.print(addr,HEX);
  Serial.print("\t");
  Serial.println(readData(addr));
}

void setup() {
  // put your setup code here, to run once:
  //setBus(false,curstate);
  
  //setBusData(curstate);
  //Serial.begin(115200);
  //Serial.println("Start!");
  startDevice();
  DDRD = 0xFF;
  PORTD = 0xF3;
}

void loop() {
  delay(1000);
  //                data output test
  //testOutput();
  //                data input test
  //testInput();
  //                DS read test
  //testDSread();

}