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setAlarmPolarity()

Arnd edited this page Jul 7, 2018 · 2 revisions

Function is called to set the alarm pin polarity. It has one boolean parameter which determines the polarity as described in table 5-10 of the datasheet.

Polarity # Alarms Description
0 One MFP high when no alarm, low on alarm
1 One MFP low when no alarm, high on alarm
0 Two MFP high when no or one alarm, low when both alarms off
1 Two MFP low when no alarm, high when either or both alarm triggered

Example:

...
MCP7940_Class MCP7940; // Create an instance of the MCP7940
...
void setup() {
  Serial.begin(SERIAL_SPEED);
  while (!MCP7940.begin()) { // Initialize RTC communications
    Serial.println("Unable to find MCP7940. Checking again in 1 second.");
    delay(1000);
  } // of loop until device is located
 uint8_t alarmType;
 MCP7940.setAlarmPolarity(true); // pin goes high when alarm is triggered
 MCP7940.setAlarm(0,7,DateTime(2017,8,5,18,30,0)); // Alarm 0 triggers at 18:30:00 on 2017-08-05
 while (MCP7940.getMFP()); // loop until an alarm is triggered
 MCP7940.setAlarmState(0,false); // Turn off the alarm
...