Mini Ultra Pro V3 with RFM95: 18μA in standby (stock, without external component)

lowpower.ino

#include <SerialFlash.h>
#include <RTCZero.h>
#include <SPI.h>
#include <RH_RF95.h>
//#include <RH_RF69.h>

// ***** CONSTANTS *****
const int radioDio0 = 2;
const int flashChipSelect = 4;
const int radioChipSelect = 5;

// Choose correct on-board radio
RH_RF95 radio(radioChipSelect, radioDio0);
//RH_RF69 radio(radioChipSelect, radioDio0);
RTCZero rtc;

/* Change these values to set the current initial time */
const uint8_t seconds = 0;
const uint8_t minutes = 00;
const uint8_t hours = 10;

/* Change these values to set the current initial date */
const uint8_t day = 20;
const uint8_t month = 2;
const uint8_t year = 17;

// ***** VARIABLES *****
unsigned char pinNumber;

void setup()
{
 // ***** Put unused pins into known state *****
  pinMode(0, INPUT_PULLUP);
  pinMode(1, INPUT_PULLUP);

  // D7-D13, A0(D14)-A5(D19), SDA(D20), SCL(D21), MISO(D22)
  for (pinNumber = 7; pinNumber <= 22; pinNumber++)
    pinMode(pinNumber, INPUT_PULLUP);
  // RX_LED (D25) & TX_LED (D26) (both LED not mounted on Mini Ultra Pro)
  pinMode(25, INPUT_PULLUP);
  pinMode(26, INPUT_PULLUP);
  // D30 (RX) & D31 (TX) of Serial
  pinMode(30, INPUT_PULLUP);
  pinMode(31, INPUT_PULLUP);
  // D34-D38 (EBDG Interface)
  for (pinNumber = 34; pinNumber <= 38; pinNumber++)
    pinMode(pinNumber, INPUT_PULLUP);
  // ***** End of unused pins state initialization *****

 if (!radio.init()){}
 radio.sleep();
 
 SerialFlash.begin(flashChipSelect);
 SerialFlash.sleep();

 pinMode(LED_BUILTIN, OUTPUT);
 
 digitalWrite(LED_BUILTIN, HIGH);

 delay(15000);

 // RTC initialization
 rtc.begin();
 rtc.setTime(hours, minutes, seconds);
 rtc.setDate(day, month, year);

 // RTC alarm setting on every 15 s resulting in 1 minute sleep period
 rtc.setAlarmSeconds(15);
 rtc.enableAlarm(rtc.MATCH_SS);
 rtc.attachInterrupt(alarmMatch);
 
 digitalWrite(LED_BUILTIN, LOW);
 USBDevice.detach();
 rtc.standbyMode();
}

void loop()
{
 // Initialize USB and attach to host (not required if not in use)
 USBDevice.init();
 USBDevice.attach();
 
 digitalWrite(LED_BUILTIN, !digitalRead(LED_BUILTIN));

 // Detach USB from host (not required if not in use)
 USBDevice.detach();
 
 // Sleep until next alarm match
 rtc.standbyMode();
}

void alarmMatch()
{

}