I2C open 100,100
I2C write &h68, 0, 2,&h0e, &h00
pause 40
I2C Close

function RTCSETREG(register,value)
I2C open 100,100
I2C write &h68, 0, 2, register, value
I2C Close
RTCSETREG=MM.I2C
end function

void DS3231::enableOscillator(bool TF, bool battery, byte frequency) {
// turns oscillator on or off. True is on, false is off.
// if battery is true, turns on even for battery-only operation,
// otherwise turns off if Vcc is off.
// frequency must be 0, 1, 2, or 3.
// 0 = 1 Hz
// 1 = 1.024 kHz
// 2 = 4.096 kHz
// 3 = 8.192 kHz (Default if frequency byte is out of range)
if (frequency > 3) frequency = 3;
// read control byte in, but zero out current state of RS2 and RS1.
byte temp_buffer = readControlByte(0) & 0b11100111;
if (battery) {
// turn on BBSQW flag
temp_buffer = temp_buffer | 0b01000000;
} else {
// turn off BBSQW flag
temp_buffer = temp_buffer & 0b10111111;
}
if (TF) {
// set ~EOSC to 0 and INTCN to zero.
temp_buffer = temp_buffer & 0b01111011;
} else {
// set ~EOSC to 1, leave INTCN as is.
temp_buffer = temp_buffer | 0b10000000;
}
// shift frequency into bits 3 and 4 and set.
frequency = frequency << 3;
temp_buffer = temp_buffer | frequency;
// And write the control bits
writeControlByte(temp_buffer, 0);
}

void DS3231::enable32kHz(bool TF) {
// turn 32kHz pin on or off
byte temp_buffer = readControlByte(1);
if (TF) {
// turn on 32kHz pin
temp_buffer = temp_buffer | 0b00001000;
} else {
// turn off 32kHz pin
temp_buffer = temp_buffer & 0b11110111;
}
writeControlByte(temp_buffer, 1);
}

bool DS3231::oscillatorCheck() {
// Returns false if the oscillator has been off for some reason.
// If this is the case, the time is probably not correct.
byte temp_buffer = readControlByte(1);
bool result = true;
if (temp_buffer & 0b10000000) {
// Oscillator Stop Flag (OSF) is set, so return false.
result = false;
}
return result;
}