Arduino Nano PI Main Discussion

[6666]

Marty see email re nano

[MartyJ1963]

Hiya George. Thanks for the info. I don't know what the problem is but now matter what driver I try it doesn't seem to work. The port shows up in Arduino IDE but when I try to program the Nano it fails. The Nano has the FT232r chip and I have nstalled the FR232r usb uart drivers. When I go into Tools for the settings I put :- Board>Arduino Nano. Processor>ATmega328P. Port>Com3. Programmer>ArduinoISP. It gives an error and doesn't program the code. If I change Processor to ATmega328P (Old Bootloader) it programs the Nano but doesn't work on my ANPI Detector pcb. When it's plugged into the ANPI I get +5v on TP4 but only -2.56v on TP3. I get the 50us wave etc on TP2. Baffled? I'm using windows 7 64 bit. Thanks, Marty.

[Qiaozhi]

Hi Alec, Hope you're well! I already tried the drivers from FTDchip. No success. The first 2 Nano's I ordered had the ch340g chip installed on board. When I installed the Nano to the ANPI i could get +5V but not -5V. Then everything went wrong after that. The Nano died! I swapped out the LT1054 about 20 times then tried about the same amount of 7660's,,nothing. George offered to test the Nano for me and the NE5534's in case they're fake but I'm yet to get to town to post them to him. Really bad weather here at the moment. I'm just trying to install the drivers on another pc at the moment for the Nano's. Regards, Marty.

It's probably something really simple, if only you could find the cause of the problem. I've not had any issues programming the ELEGOO NANO 3.0 boards that I have here using either Windows 10 or Linux Mint.

Here are my settings:

Windows 10 with Arduino IDE V1.8.13
Tools > Board: > Arduino Nano
Tools > Processor: > Atmega328P
Tools > Port: > COM8

Linux Mint 18.1 Cinnamon 3.2.7 with Arduino IDE V1.8.13
Tools > Board: > Arduino Nano
Tools > Processor: > Atmega328P
Tools > Port: > /dev/tty/USB0

In Windows 10 there were two USB ports shown in the list, so I just tried them in order to find out which one was connected to the Nano. The easiest way to test this is to select Tools > Get Board Info. Only one of the selections will return any data.

Marty - Our friendly postie will take any letters or parcels when he comes to the door. You can buy postage online on the Post Office site, print off a label and attach it to a jiffy bag. If your postie is the same, it would save you a trip into town.

[MartyJ1963]

Hi Alec, Hope you're well! I already tried the drivers from FTDchip. No success. The first 2 Nano's I ordered had the ch340g chip installed on board. When I installed the Nano to the ANPI i could get +5V but not -5V. Then everything went wrong after that. The Nano died! I swapped out the LT1054 about 20 times then tried about the same amount of 7660's,,nothing. George offered to test the Nano for me and the NE5534's in case they're fake but I'm yet to get to town to post them to him. Really bad weather here at the moment. I'm just trying to install the drivers on another pc at the moment for the Nano's. Regards, Marty.

[surfdetector]

I couldn't zero the 5534 or get the -5v on the both ANPI's I built.

Hi Marty,

• Do you have +5 volts at TP4?
• What do you have at TP2?
• Your ability to zero out the pre-amp should not be related to the Arduino
• Check out this page
• https://ftdichip.com/drivers/vcp-drivers/

[MartyJ1963]

@Gallico58, Thanks for the reply. I have tried everything with no success. The drivers I installed, multiple times, do not seem to work as the red light on the Nano continues to glow. I am at a loss what to try next. Thanks anyway for your help. Regards, Marty.

[gallico58]

Hi Marty, I had the same problems as you, sometimes with nano did not see the com port in windows xp, I made several attempts then I don't know how I managed it.
if you can try linux.
on the web I found this explanation but I have not tried

"If you own an Arduino Nano 3.0 you may have connection problems, this manifests itself with problems so that the module is recognized by the PC once connected for example for loading a program.
The problem is due to the fact that Gravitech designers in the first models of the module (now the problem should be solved) have not left free, this is not connected to ground, the PIN 26 (test) of the U2 Type FT232RL integration which serves as an interface between the USB port and the ATMega 368 processor.
As reported on the device's datasheet, this pin must, for normal operations, be connected to GND. If you own an Arduino Nano 3.0 you may have connection problems, this manifests itself with problems so that the module is recognized by the PC once connected for example for loading a program.
The problem is due to the fact that Gravitech designers in the first models of the module (now the problem should be solved) have not left free, this is not connected to ground, the PIN 26 (test) of the U2 Type FT232RL integration which serves as an interface between the USB port and the ATMega 368 processor.
As reported on the device's datasheet, this pin must, for normal operations, be connected to GND."

https://win.adrirobot.it/arduino/arduino_nano/scheda_arduino_nano.htm

[MartyJ1963]

Hi everyone. I'm having a real difficult time with my new Arduino Nano V.3 boards. The first 2 Nano's I ordered had the ch340g chip on board and I couldn't zero the 5534 or get the -5v on the both ANPI's I built. I received my 2 x Nano boards today that have the FT232R UART Chip on board and cannot get my pc to recognise them or install drivers for them. I have downloaded original drivers from FTI etc and other sites and still can't get the pc to recognise it or install it correctly. It's driving me absolutely daft! as I've been at this now for weeks! Can anyone offer any suggestions or alternative drivers or procedures etc please? Thanks, Marty.

[Qiaozhi]

Amazon have announced that paperback printing will begin launching in Australia on May 19, 2021.

No longer will our Australian friends have to order books via the USA, or at inflated prices from third-party book sellers.

[gallico58]

Hi George, however it may be a subjective problem, it may be that my construction on a breadboard is not so perfect, I would leave everything as an original from a book that works well, maybe opening a dedicated post on modifications would be more appropriate, what do you think?
however the audio and oscilloscope pulses in a certain position of the potentiometer you describe were really my problem, perhaps I had not explained myself well.
but when I replaced the code with that of Teleno they practically disappeared ........ Mystery!

[Qiaozhi]

I first tested the original code in the ANPI, and there was a small amount of jitter on the main sample delay, probably less than 100ns.
Then I tested Teleno's code and the sample delay was rock solid.

However, there was no discernible difference in performance between the two versions as far as the audio response was concerned. I suspect this is because any small jitter is being integrated out in the following stages.

There was one side-effect of adding hysteresis to the sample delay pot measurement though. I discovered that it was possible to adjust the pot to a position where it caused a repeating beep in the audio output, and the sample delay (on the scope) jumped around between two settings.

The adjustment of the sample delay was also much smoother in the original version.

Maybe a running average would be a better solution if you're concerned about the jitter.

[Qiaozhi]

Thanks Teleno and gallico58.

I'll load the modified code tonight and compare the difference.
Personally I'm really pleased with the way the Arduino Nano PI has turned out. It's a great platform for learning about the Arduino, and provides a lot of flexibility for further experiments.

[Teleno]

Thanks Teleno, it works well, more stable.
ide was giving me error I had to insert, I hope in the right place the line "word Potread = 0;" this link for a video:

https://drive.google.com/file/d/1cUw...ew?usp=sharing

Good to hear.

I made the error of inserting "word potValue" where I should have written "word potRead".

Corrected program:

// Arduino Pulse Induction Metal Detector

// Pin assignments
byte txPin = 8;          // Assign pin 8 to TX output
byte mainSamplePin = 9;  // Assign pin 9 to main sample pulse
byte efeSamplePin = 10;  // Assign pin 10 to EFE sample pulse
byte audioPin = 11;      // Assign pin 11 to audio chopper
byte boostPin = 12;      // Assign pin 12 to boost switch
byte delayPin = A0;      // Assign delay pot to A0


// Program constants
const float normalPower = 50E-6;       // Normal TX-on time (50us)
const float boostPower = 100E-6;       // Boost TX-on time (100us)
const float clockCycle = 62.5E-9;      // Time for one clock cycle (1/16MHz)
const unsigned long maxCount = 65535;  // Value of 2^16 - 1
const byte readDelayLimit = 100;       // Wait 100 TX periods (100ms) before reading delay pot
const byte mosfetOn = HIGH;            // Mosfet turns on when transmitter input high
const byte mosfetOff = LOW;            // Mosfet turns off when transmitter input low
const byte syncDemodOn = LOW;          // Sample gate turns on when input high
const byte syncDemodOff = HIGH;        // Sample gate turns off when input low


// Detector timings
float txOn = normalPower;        // TX-on time using normal power mode
float defMainDelay = 10E-6;      // Default main sample delay (10us)
float mainDelay = defMainDelay;  // Main sample pulse delay
float mainSample = 50E-6;        // Main sample pulse width (50us)
float efeDelay = 240E-6;         // EFE sample pulse delay (240us)
float efeSample = mainSample;    // EFE sample pulse width (same as main sample)
float txPeriod = 1E-3;           // TX period (1ms)


// Timing offsets
float txOnOffset = 3E-6;         // TX-on pulse offset (3us)
float mainDelayOffset = 4.2E-6;  // Main delay pulse offset (4.2us)
float mainSampleOffset = 3E-6;   // Main sample pulse offset (3us)
float efeDelayOffset = 12E-6;    // EFE delay pulse offset (12us)
float efeSampleOffset = 4E-6;    // EFE sample pulse offset (4us)
float txPeriodOffset = 30E-6;    // TX period offset (30us)


// Program variables
float temp1, temp2, temp3, temp4, temp5, temp6;  // Intermediate calculation variables
word txOnCount;                                  // TX pulse
word mainDelayCount;                             // Main sample delay
word mainSampleCount;                            // Main sample pulse
word efeDelayCount;                              // EFE sample delay
word efeSampleCount;                             // EFE sample pulse
word txPeriodCount;                              // TX period
word potRead;                                    // Voltage at the delay pot
word delayVal = 0;                               // Delay pot value
boolean readDelayPot = false;                    // Delay pot read (true or false)
byte intState = 0;                               // Interrupt state machine
byte readDelayCounter = 0;                       // Read delay pot counter


void setup() {
  pinMode(txPin, OUTPUT);           // Set TX pin to output mode
  pinMode(mainSamplePin, OUTPUT);   // Set main sample pin to output mode
  pinMode(efeSamplePin, OUTPUT);    // Set EFE sample pin to output mode
  pinMode(boostPin, INPUT_PULLUP);  // Set Boost switch pin to input mode with pullup resistor
  calcTimerValues();                // Calculate all timer values
  noInterrupts();                   // Disable interrupts
  TCCR1A = 0;                       // Initialize Timer1 registers
  TCCR1B = 0;
  TIMSK0 = 0;                       // Clear Timer0 mask register to eliminate jitter
  TCNT1 = txOnCount;                // Load Timer1 with TX-on count
  TCCR1B |= (1 << CS10);            // No prescaling for Timer1
  TIMSK1 |= (1 << TOIE1);           // Enable Timer1 overflow interrupt
  interrupts();                     // Enable interrupts
  analogWrite(audioPin, 127);       // Set audioPin with 50% duty cycle PWM
}


void calcTimerValues() {
  if (digitalRead(boostPin) == HIGH) {                   // Get boost switch position
    txOn = normalPower;                                  // Set TX-on to 50us if HIGH
  } else {
    txOn = boostPower;                                   // Set TX-on to 100us if LOW
  }
  temp1 = (txOn - txOnOffset) / clockCycle;
  txOnCount = maxCount - int(temp1);                     // TX-on count for Timer1
  temp2 = (mainDelay - mainDelayOffset) / clockCycle;
  mainDelayCount = maxCount - int(temp2);                // Main sample delay count for Timer1
  temp3 = (mainSample - mainSampleOffset) / clockCycle;
  mainSampleCount = maxCount - int(temp3);               // Main sample pulse count for Timer1
  temp4 = (efeDelay - efeDelayOffset) / clockCycle;
  temp4 -= temp3 + temp2;
  efeDelayCount = maxCount - int(temp4);                 // EFE sample delay count for Timer1
  temp5 = (efeSample - efeSampleOffset) / clockCycle;
  efeSampleCount = maxCount - int(temp5);                // EFE sample pulse count for Timer 1
  temp6 = (txPeriod - txPeriodOffset) / clockCycle;
  temp6 -= temp1 + temp2 + temp3 + temp4 + temp5;
  txPeriodCount = maxCount - int(temp6);                 // TX period count for Timer1
}


ISR(TIMER1_OVF_vect) {
  switch (intState) {
    case 0:
      TCNT1 = txOnCount;                           // Load Timer1 with TX-ON count
      digitalWrite(txPin, mosfetOn);               // Turn on Mosfet
      intState = 1;
      break;
    case 1:
      TCNT1 = mainDelayCount;                      // Load Timer1 with main sample delay count
      digitalWrite(txPin, mosfetOff);              // Turn off Mosfet
      intState = 2;
      break;
    case 2:
      TCNT1 = mainSampleCount;                     // Load Timer1 with main sample pulse count
      digitalWrite(mainSamplePin, syncDemodOn);    // Turn on main sample gate
      intState = 3;
      break;
    case 3:
      TCNT1 = efeDelayCount;                       // Load Timer1 with EFE sample delay count
      digitalWrite(mainSamplePin, syncDemodOff);   // Turn off main sample gate
      if (readDelayPot == false) {                 // Check if read delay pot flag is false
        readDelayCounter++;                        // Increment read delay counter
        if (readDelayCounter >= readDelayLimit) {  // Check if read delay counter has reached limit
          readDelayPot = true;                     // Enable read of delay pot
          readDelayCounter = 0;                    // Clear read delay counter
        }
      }
      intState = 4;
      break;
    case 4:
      TCNT1 = efeSampleCount;                      // Load Timer1 with EFE sample pulse count
      digitalWrite(efeSamplePin, syncDemodOn);     // Turn on EFE sample gate
      intState = 5;
      break;
    case 5:
      TCNT1 = txPeriodCount;                       // Load Timer1 with TX period count
      digitalWrite(efeSamplePin, syncDemodOff);    // Turn off EFE sample gate
      intState = 0;
      break;
    default:
      intState = 0;
      break;
  }
}


void loop() {
  if (readDelayPot == true) {
    potRead = analogRead(delayPin);                        // Read the delay pot
    /* update delayVal with hysteresis to avoid ADC and pot jitter */                       
    if (potRead > (delayVal + 16)) delayVal = potRead - 16;
    else if (potRead < (delayVal  - 16)) delayVal = potRead + 16;
    mainDelay = defMainDelay + delayVal * clockCycle;      // Offset main sample delay
    calcTimerValues();                                     // Calculate new timer values
    readDelayPot = false;                                  // Set read delay pot flag to false
  }
}

[gallico58]

Thanks Teleno, it works well, more stable.
ide was giving me error I had to insert, I hope in the right place the line "word Potread = 0;" this link for a video:

https://drive.google.com/file/d/1cUwc_i639Jty_PTi60ST5i_G8Ko7EoTu/view?usp=sharing

// Arduino Pulse Induction Metal Detector


// Pin assignments
byte txPin = 8; // Assign pin 8 to TX output
byte mainSamplePin = 9; // Assign pin 9 to main sample pulse
byte efeSamplePin = 10; // Assign pin 10 to EFE sample pulse
byte audioPin = 11; // Assign pin 11 to audio chopper
byte boostPin = 12; // Assign pin 12 to boost switch
byte delayPin = A0; // Assign delay pot to A0




// Program constants
const float normalPower = 50E-6; // Normal TX-on time (50us)
const float boostPower = 100E-6; // Boost TX-on time (100us)
const float clockCycle = 62.5E-9; // Time for one clock cycle (1/16MHz)
const unsigned long maxCount = 65535; // Value of 2^16 - 1
const byte readDelayLimit = 100; // Wait 100 TX periods (100ms) before reading delay pot
const byte mosfetOn = HIGH; // Mosfet turns on when transmitter input high
const byte mosfetOff = LOW; // Mosfet turns off when transmitter input low
const byte syncDemodOn = LOW; // Sample gate turns on when input high
const byte syncDemodOff = HIGH; // Sample gate turns off when input low




// Detector timings
float txOn = normalPower; // TX-on time using normal power mode
float defMainDelay = 10E-6; // Default main sample delay (10us)
float mainDelay = defMainDelay; // Main sample pulse delay
float mainSample = 50E-6; // Main sample pulse width (50us)
float efeDelay = 240E-6; // EFE sample pulse delay (240us)
float efeSample = mainSample; // EFE sample pulse width (same as main sample)
float txPeriod = 1E-3; // TX period (1ms)




// Timing offsets
float txOnOffset = 3E-6; // TX-on pulse offset (3us)
float mainDelayOffset = 4.2E-6; // Main delay pulse offset (4.2us)
float mainSampleOffset = 3E-6; // Main sample pulse offset (3us)
float efeDelayOffset = 12E-6; // EFE delay pulse offset (12us)
float efeSampleOffset = 4E-6; // EFE sample pulse offset (4us)
float txPeriodOffset = 30E-6; // TX period offset (30us)




// Program variables
float temp1, temp2, temp3, temp4, temp5, temp6; // Intermediate calculation variables
word txOnCount; // TX pulse
word mainDelayCount; // Main sample delay
word mainSampleCount; // Main sample pulse
word efeDelayCount; // EFE sample delay
word efeSampleCount; // EFE sample pulse
word txPeriodCount; // TX period
word potRead = 0;
word potValue; // Voltage at the delay pot
word delayVal = 0; // Delay pot value
boolean readDelayPot = false; // Delay pot read (true or false)
byte intState = 0; // Interrupt state machine
byte readDelayCounter = 0; // Read delay pot counter




void setup() {
pinMode(txPin, OUTPUT); // Set TX pin to output mode
pinMode(mainSamplePin, OUTPUT); // Set main sample pin to output mode
pinMode(efeSamplePin, OUTPUT); // Set EFE sample pin to output mode
pinMode(boostPin, INPUT_PULLUP); // Set Boost switch pin to input mode with pullup resistor
calcTimerValues(); // Calculate all timer values
noInterrupts(); // Disable interrupts
TCCR1A = 0; // Initialize Timer1 registers
TCCR1B = 0;
TIMSK0 = 0; // Clear Timer0 mask register to eliminate jitter
TCNT1 = txOnCount; // Load Timer1 with TX-on count
TCCR1B |= (1 << CS10); // No prescaling for Timer1
TIMSK1 |= (1 << TOIE1); // Enable Timer1 overflow interrupt
interrupts(); // Enable interrupts
analogWrite(audioPin, 127); // Set audioPin with 50% duty cycle PWM
}




void calcTimerValues() {
if (digitalRead(boostPin) == HIGH) { // Get boost switch position
txOn = normalPower; // Set TX-on to 50us if HIGH
} else {
txOn = boostPower; // Set TX-on to 100us if LOW
}
temp1 = (txOn - txOnOffset) / clockCycle;
txOnCount = maxCount - int(temp1); // TX-on count for Timer1
temp2 = (mainDelay - mainDelayOffset) / clockCycle;
mainDelayCount = maxCount - int(temp2); // Main sample delay count for Timer1
temp3 = (mainSample - mainSampleOffset) / clockCycle;
mainSampleCount = maxCount - int(temp3); // Main sample pulse count for Timer1
temp4 = (efeDelay - efeDelayOffset) / clockCycle;
temp4 -= temp3 + temp2;
efeDelayCount = maxCount - int(temp4); // EFE sample delay count for Timer1
temp5 = (efeSample - efeSampleOffset) / clockCycle;
efeSampleCount = maxCount - int(temp5); // EFE sample pulse count for Timer 1
temp6 = (txPeriod - txPeriodOffset) / clockCycle;
temp6 -= temp1 + temp2 + temp3 + temp4 + temp5;
txPeriodCount = maxCount - int(temp6); // TX period count for Timer1
}




ISR(TIMER1_OVF_vect) {
switch (intState) {
case 0:
TCNT1 = txOnCount; // Load Timer1 with TX-ON count
digitalWrite(txPin, mosfetOn); // Turn on Mosfet
intState = 1;
break;
case 1:
TCNT1 = mainDelayCount; // Load Timer1 with main sample delay count
digitalWrite(txPin, mosfetOff); // Turn off Mosfet
intState = 2;
break;
case 2:
TCNT1 = mainSampleCount; // Load Timer1 with main sample pulse count
digitalWrite(mainSamplePin, syncDemodOn); // Turn on main sample gate
intState = 3;
break;
case 3:
TCNT1 = efeDelayCount; // Load Timer1 with EFE sample delay count
digitalWrite(mainSamplePin, syncDemodOff); // Turn off main sample gate
if (readDelayPot == false) { // Check if read delay pot flag is false
readDelayCounter++; // Increment read delay counter
if (readDelayCounter >= readDelayLimit) { // Check if read delay counter has reached limit
readDelayPot = true; // Enable read of delay pot
readDelayCounter = 0; // Clear read delay counter
}
}
intState = 4;
break;
case 4:
TCNT1 = efeSampleCount; // Load Timer1 with EFE sample pulse count
digitalWrite(efeSamplePin, syncDemodOn); // Turn on EFE sample gate
intState = 5;
break;
case 5:
TCNT1 = txPeriodCount; // Load Timer1 with TX period count
digitalWrite(efeSamplePin, syncDemodOff); // Turn off EFE sample gate
intState = 0;
break;
default:
intState = 0;
break;
}
}




void loop() {
if (readDelayPot == true) {
potRead = analogRead(delayPin); // Read the delay pot
if (potRead > (delayVal + 16)) delayVal = potRead - 16;
else if (potRead < (delayVal - 16)) delayVal = potRead + 16;
mainDelay = defMainDelay + delayVal * clockCycle; // Offset main sample delay
calcTimerValues(); // Calculate new timer values
readDelayPot = false; // Set read delay pot flag to false
}
}

[Teleno]

Teleno is most likely correct that the Delay pot is the cause, although I'm a bit surprised that any audio jitter would be that noticeable for a change as small as 62.5ns.

The maximum accuracy of the ADC is 3.5 bits (page 265, table 28.9 of the Atmega328P datasheet). Thus the ADC value can vary by 1.1% from one measurement to the next for the same pot position.
2^3.5 is 11.3, so a jitter of 11.3 x 62.5ns = 706 ns can be expected from this alone.
Then the potentiometer's own jitter on top of it, a well known phenomenon: Potentiometer jitter
The interrupt jitter is about 1 cycle because most of the instructions take 1 or 2 cycles, very rarely 3 or more, and their execution is completed before serving the interrupt.

Thanks Teleno and Qiaozhi, I will try to change the code, I am quite good with the soldering iron but I am denied in software programming.
sorry also my bad english, i use the translator!

Try the hysteresis code first. The new .ino file would be like this:

// Arduino Pulse Induction Metal Detector

// Pin assignments
byte txPin = 8;          // Assign pin 8 to TX output
byte mainSamplePin = 9;  // Assign pin 9 to main sample pulse
byte efeSamplePin = 10;  // Assign pin 10 to EFE sample pulse
byte audioPin = 11;      // Assign pin 11 to audio chopper
byte boostPin = 12;      // Assign pin 12 to boost switch
byte delayPin = A0;      // Assign delay pot to A0


// Program constants
const float normalPower = 50E-6;       // Normal TX-on time (50us)
const float boostPower = 100E-6;       // Boost TX-on time (100us)
const float clockCycle = 62.5E-9;      // Time for one clock cycle (1/16MHz)
const unsigned long maxCount = 65535;  // Value of 2^16 - 1
const byte readDelayLimit = 100;       // Wait 100 TX periods (100ms) before reading delay pot
const byte mosfetOn = HIGH;            // Mosfet turns on when transmitter input high
const byte mosfetOff = LOW;            // Mosfet turns off when transmitter input low
const byte syncDemodOn = LOW;          // Sample gate turns on when input high
const byte syncDemodOff = HIGH;        // Sample gate turns off when input low


// Detector timings
float txOn = normalPower;        // TX-on time using normal power mode
float defMainDelay = 10E-6;      // Default main sample delay (10us)
float mainDelay = defMainDelay;  // Main sample pulse delay
float mainSample = 50E-6;        // Main sample pulse width (50us)
float efeDelay = 240E-6;         // EFE sample pulse delay (240us)
float efeSample = mainSample;    // EFE sample pulse width (same as main sample)
float txPeriod = 1E-3;           // TX period (1ms)


// Timing offsets
float txOnOffset = 3E-6;         // TX-on pulse offset (3us)
float mainDelayOffset = 4.2E-6;  // Main delay pulse offset (4.2us)
float mainSampleOffset = 3E-6;   // Main sample pulse offset (3us)
float efeDelayOffset = 12E-6;    // EFE delay pulse offset (12us)
float efeSampleOffset = 4E-6;    // EFE sample pulse offset (4us)
float txPeriodOffset = 30E-6;    // TX period offset (30us)


// Program variables
float temp1, temp2, temp3, temp4, temp5, temp6;  // Intermediate calculation variables
word txOnCount;                                  // TX pulse
word mainDelayCount;                             // Main sample delay
word mainSampleCount;                            // Main sample pulse
word efeDelayCount;                              // EFE sample delay
word efeSampleCount;                             // EFE sample pulse
word txPeriodCount;                              // TX period
word potValue;                                   // Voltage at the delay pot
word delayVal = 0;                               // Delay pot value
boolean readDelayPot = false;                    // Delay pot read (true or false)
byte intState = 0;                               // Interrupt state machine
byte readDelayCounter = 0;                       // Read delay pot counter


void setup() {
  pinMode(txPin, OUTPUT);           // Set TX pin to output mode
  pinMode(mainSamplePin, OUTPUT);   // Set main sample pin to output mode
  pinMode(efeSamplePin, OUTPUT);    // Set EFE sample pin to output mode
  pinMode(boostPin, INPUT_PULLUP);  // Set Boost switch pin to input mode with pullup resistor
  calcTimerValues();                // Calculate all timer values
  noInterrupts();                   // Disable interrupts
  TCCR1A = 0;                       // Initialize Timer1 registers
  TCCR1B = 0;
  TIMSK0 = 0;                       // Clear Timer0 mask register to eliminate jitter
  TCNT1 = txOnCount;                // Load Timer1 with TX-on count
  TCCR1B |= (1 << CS10);            // No prescaling for Timer1
  TIMSK1 |= (1 << TOIE1);           // Enable Timer1 overflow interrupt
  interrupts();                     // Enable interrupts
  analogWrite(audioPin, 127);       // Set audioPin with 50% duty cycle PWM
}


void calcTimerValues() {
  if (digitalRead(boostPin) == HIGH) {                   // Get boost switch position
    txOn = normalPower;                                  // Set TX-on to 50us if HIGH
  } else {
    txOn = boostPower;                                   // Set TX-on to 100us if LOW
  }
  temp1 = (txOn - txOnOffset) / clockCycle;
  txOnCount = maxCount - int(temp1);                     // TX-on count for Timer1
  temp2 = (mainDelay - mainDelayOffset) / clockCycle;
  mainDelayCount = maxCount - int(temp2);                // Main sample delay count for Timer1
  temp3 = (mainSample - mainSampleOffset) / clockCycle;
  mainSampleCount = maxCount - int(temp3);               // Main sample pulse count for Timer1
  temp4 = (efeDelay - efeDelayOffset) / clockCycle;
  temp4 -= temp3 + temp2;
  efeDelayCount = maxCount - int(temp4);                 // EFE sample delay count for Timer1
  temp5 = (efeSample - efeSampleOffset) / clockCycle;
  efeSampleCount = maxCount - int(temp5);                // EFE sample pulse count for Timer 1
  temp6 = (txPeriod - txPeriodOffset) / clockCycle;
  temp6 -= temp1 + temp2 + temp3 + temp4 + temp5;
  txPeriodCount = maxCount - int(temp6);                 // TX period count for Timer1
}


ISR(TIMER1_OVF_vect) {
  switch (intState) {
    case 0:
      TCNT1 = txOnCount;                           // Load Timer1 with TX-ON count
      digitalWrite(txPin, mosfetOn);               // Turn on Mosfet
      intState = 1;
      break;
    case 1:
      TCNT1 = mainDelayCount;                      // Load Timer1 with main sample delay count
      digitalWrite(txPin, mosfetOff);              // Turn off Mosfet
      intState = 2;
      break;
    case 2:
      TCNT1 = mainSampleCount;                     // Load Timer1 with main sample pulse count
      digitalWrite(mainSamplePin, syncDemodOn);    // Turn on main sample gate
      intState = 3;
      break;
    case 3:
      TCNT1 = efeDelayCount;                       // Load Timer1 with EFE sample delay count
      digitalWrite(mainSamplePin, syncDemodOff);   // Turn off main sample gate
      if (readDelayPot == false) {                 // Check if read delay pot flag is false
        readDelayCounter++;                        // Increment read delay counter
        if (readDelayCounter >= readDelayLimit) {  // Check if read delay counter has reached limit
          readDelayPot = true;                     // Enable read of delay pot
          readDelayCounter = 0;                    // Clear read delay counter
        }
      }
      intState = 4;
      break;
    case 4:
      TCNT1 = efeSampleCount;                      // Load Timer1 with EFE sample pulse count
      digitalWrite(efeSamplePin, syncDemodOn);     // Turn on EFE sample gate
      intState = 5;
      break;
    case 5:
      TCNT1 = txPeriodCount;                       // Load Timer1 with TX period count
      digitalWrite(efeSamplePin, syncDemodOff);    // Turn off EFE sample gate
      intState = 0;
      break;
    default:
      intState = 0;
      break;
  }
}


void loop() {
  if (readDelayPot == true) {
    potRead = analogRead(delayPin);                   // Read the delay pot
    if (potRead > (delayVal + 16)) delayVal = potRead - 16;
    else if (potRead < (delayVal  - 16)) delayVal = potRead + 16;
    mainDelay = defMainDelay + delayVal * clockCycle;  // Offset main sample delay
    calcTimerValues();                                 // Calculate new timer values
    readDelayPot = false;                              // Set read delay pot flag to false
  }
}