I have recently been made aware of an interesting temperature compensated Real Time Clock chip, the
DS3231. This information is archived here for my later use.
The chip contains its own Tuning Fork Oscillator element, and therefore very few external parts are needed. The chip was introduced in 2005 and available from
Mouser for about $10.00 ea.
From the datasheet, the DS3231 provides:
- Accuracy ±2ppm from 0°C to +40°C
- Accuracy ±3.5ppm from -40°C to +85°C
- Battery Backup Input for Continuous Timekeeping
- Operating Temperature Ranges
- Commercial: 0°C to +70°C
- Industrial: -40°C to +85°C
- Low-Power Consumption
- Real-Time Clock Counts Seconds, Minutes, Hours, Day, Date, Month, and Year with Leap Year Compensation Valid Up to 2100
- Two Time-of-Day Alarms
- Programmable Square-Wave Output
- Fast (400kHz) I²C Interface
- 3.3V Operation
- Digital Temp Sensor Output: ±3°C Accuracy
- Register for Aging Trim
- Active-Low RST Output/Pushbutton Reset Debounce Input
For my use in my Beacon Projects; the programmable alarms and once-per-minute interrupt output could be used for the two minute WSPR timing requirements, or accurate QRSS start of signal timing. The Temperature Output could be used for remote environmental sensing, maybe for balloon payload data.
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