/*
  lp_BLE_compartor
  This sketch sets up a Nordic BLE UART and sends the pin input level Above/Below reference level on each change
  (c)2018 Forward Computing and Control Pty. Ltd.
  This example code is in the public domain.
*/

#include <lp_BLESerial.h>
#include <lp_comparator.h>

// Pin 13 has an LED connected on most Arduino boards, including NanoV2
int led = 13;
int comparatorPin = 2; // D2/A2
lp_BLESerial ble;

void setup() {
  pinMode(comparatorPin, INPUT_PULLDOWN);  // set compare pin with INPUT_PULLUP or INPUT_PULLDOWN to prevent floating pin triggers
  // but the internal pullup/pulldown resistor is ~13K which draws an extra 254uA when INPUT_PULLUP is grounded or INPUT_PULLDOWN is connected to Vdd
  // for very low power use pinMode(2, INPUT) and supply a high value external pullup or pulldown resistor e.g. 100K draws ~33uA
  // ADVERTISING ~90uA, CONNECTED ~90uA when pin input grounded. i.e. LED off and no current through pull-down resistor
  pinMode(led, OUTPUT); // initialize the digital pin as an output.
  ble.setName("Pin Change"); // set advertised name, default name is "Nordic BLE UART"
  ble.begin(); // start advertising and be ready to accept connections
  lp_comparator_start(comparatorPin, REF_8_16Vdd, handlePinLevelChange); // always triggers pin LOW first, then if pin HIGH, will trigger HIGH
}

void loop() {
  sleep(); // just sleep here waiting a trigger
  while (ble.available()) {
    int i = ble.read(); // clear BLE recieve buffer and ignore
  }
}

// called when pin changes state, pinState is state detected,
// HIGH when Above and LOW when Below the reference voltage
void handlePinLevelChange(int pinState) {
  if (ble.isConnected()) {
    ble.print(millis()); ble.print(',');
    ble.print((pinState == HIGH) ? 'H' : 'L');  ble.println();
  }
  digitalWrite(led, pinState);   // turn the LED on when Above
}