/* Avcomm_HF_Sequencer 
  04 Sept_21 Version 1_0
  HF_sequencer_1-0 (removed from HF_Travceiver_ver_1 small)
  D3 is Ptt-Bias to Amp, A6 is Ptt input, D2 is drive inhibit relay
  D4 is Antenna-coax relay
*/

  //variables for the sequencer
  int inhibit=2; // on pin Digital 2 INHIBIT
  int ptt=A6; // PTT input on pin Analog A6
  int bias=3; // Bias enable on amp
  int relay=4; // output Relay
  
  int tx = 1000; // put ptt into receive
     

void setup() 
{
 //setup sequencer
  
  pinMode(inhibit, OUTPUT); // set inhibit pin as an output
  pinMode(ptt, INPUT); //set PTT input pin as an input
  pinMode(bias, OUTPUT);  //bias pin set as an output
  pinMode(relay, OUTPUT);  //relay pin set as an output

/* The next line may not work or be needed, depending on ext ptt cct 
  voltage and impedence and manufacturer of Arduino nano
  To be safe use a 47K external pullup resistor to +5v.
  do not exceed 5V from the external ptt rail  if connected
  to other equipment 
*/
  
// pinMode(ptt, INPUT_PULLUP); 
 
  digitalWrite(inhibit, LOW); // set inhibit to off
  analogWrite(ptt, 255); // set ppt high
  digitalWrite(bias, LOW); // set amp to off
  digitalWrite(relay, LOW); // set output relay to Rx (off)
  
  delay(3000); // wait 3 seconds before starting
  
  Serial.begin(9600);
  
  Serial.println("Sequencer start"); Serial.println("");  
  
  
}
/**************************************************************************/
/*
    Arduino loop function, called once 'setup' is complete (your own code
    should go below) -  A sample sequencer code follows - check that it has
    the right sequence and delay times for your hardware
*/
/**************************************************************************/
void loop() 
{
 // code for sequencer
 
     int tx = analogRead(ptt);
 
    if (tx <= 10) { // go to transmit

//  ptt detected as earthed; - start Tx sequence otherwise jump    
    
      digitalWrite(relay, HIGH); //RF output relay set to Tx  
      delay(60); // 60 ms to let the antenna relay switch
      digitalWrite(bias, HIGH); //Amp bias energised ON
      delay(30); // 30 ms to let the bias relay switch
      digitalWrite(inhibit, HIGH); //apply the drive to PA
      delay(60); // 60 ms to let the inhibit relay switch
 //Serial.print
      Serial.print(tx);
      Serial.print("  \r\n");   // Print a return and new line 
      Serial.print("Transmit"); 
    }
  
    if (tx >= 10) { // go to receive
      
//    ptt detected as earthed to start Receive sequence

      digitalWrite(inhibit, LOW); //Drive immediately removed from PA
      delay(60); // 60 ms delay for inhibit relay to operate
      digitalWrite(bias, LOW); //Amplifier bias volts terned off
      delay(60); // 60 ms to let the bias volts goto zero
      digitalWrite(relay, LOW); //RF output relay set to Receive
      
      Serial.print(tx);
      Serial.print("  \r\n");   // Print a return and new line 
      Serial.print("Receive"); 
      
    }    
  delay(10); // delay and go back and test for a change in tx/rx  
  
}