RX8010 timer interrupt

tried a forum search
didn't find anything
has anyone used an Epson RX8010 RTC to generate a fixed interval interrupt?

it looks like it should be doable, but I'm struggling ...

The RX8010SJ runs on 5V so you should be able to connect the IRQ1 and IRQ2 pins to Pin 2 and Pin 3, the two external interrupts of the Arduino UNO. Since IRQ1 is an Open Drain output, be sure to provide a pull-up resistor. Use attachInterrupt() to associate a function with an interrupt.

Keep your interrupt functions short!

hello John
thanks

in fact Arduino and RTC both running off a single 3.7 volt LiPo

interrupt IRQ1 is attached to D4
pinMode INPUT_PULLUP

interrupt vector just sets a boolean "we got woken up"
it's enough that it wakes a slumbering 'duino

I was struggling to get the RX8010 to generate IRQ1 every 55 seconds
spent ages writing a really neat routine

then noticed I forgot to call it!!!!! d'oh!

here's my code for amusement ...

// tick indicator
//===============
volatile boolean tick;

//=================================
ISR(PCINT2_vect)
{
  // handle pin change interrupt for D0 to D7 here
  //===============================================

  tick = true;
  
  // end of PCINT2_vect
  //===================
} 

//=================================
void setupWakeTick(void)
{
  // pin change interrupt
  //=====================
  PCMSK2 |= bit (PCINT20); // want pin D4
  PCIFR  |= bit (PCIF2);   // clear any outstanding interrupts
  PCICR  |= bit (PCIE2);   // enable pin change interrupts for D0 to D7

  tick = false;
}

//=================================
void RX8010initClock(void)
{
  // initialise clock chip
  //======================
  RX8010writeReg(RES_17, 0xD8);
  RX8010writeReg(MIN_ALARM, 0x00);
  RX8010writeReg(HOUR_ALARM, 0x00);
  RX8010writeReg(CON_REG, 0x00);
  RX8010writeReg(MIN_ALARM, 0x00);
  RX8010writeReg(HOUR_ALARM, 0x00);
  RX8010writeReg(WADA_ALARM, 0x00);
  RX8010writeReg(RES_30, 0x00);
  
  RX8010writeReg(RES_31, 0x08);
  
  // !TE and TSEL2, TSEL1, TSEL0
  //         -------------------
  //             0      1      0
  //                         1Hz
  //============================
  RX8010writeReg(EXT_REG, TSEL1);
  
  // tick counter
  //=============
  RX8010writeReg(TIMER1, 0);
  RX8010writeReg(TIMER0, 55);

  // no alarms
  // but we do want timer interrupts
  //================================
  RX8010writeReg(CON_REG, TIE);

  // interrupt on IRQ1
  //==================
  RX8010writeReg(IRQ_CON, TMPIN);

  // now enable the timer
  //=====================
  RX8010writeReg(EXT_REG, TSEL1 + TE);

  // set and clear TSTP
  //===================
  RX8010writeReg(CON_REG, TIE + TSTP);
  RX8010writeReg(CON_REG, TIE);

  // clear flags
  //============
  RX8010writeReg(FLAG_REG, 0x00);
}

Hello gentlemen,
Can you share which library are you using?
Thank you,
Dave