Real time clock (DS1302) เป็นโมดูลนาฬิกาที่มาพร้อมกับ Library สามารถใช้งานง่าย ใช้ไฟเลี้ยง 2-5.5V

____________________________________________________________________________

สอนการใช้งานบอร์ด Arduino กับ RTC real time clock module

____________________________________________________________________________

The DS1302RTC library is a drop-in replacement for the DS1307RTC.h library by Michael Margolis that is supplied with the Arduino Time library above. To change from using aDS1307 RTC to a DS1302 RTC, it is only necessary to change the #include statement to include DS1302RTC.h instead of DS1307RTC.h

This library also implements functions to support the additional Features :
2.0V to 5.5V Full Operation
Uses Less than 300nA at 2.0V
1. Real Time Clock read/write (8 bytes)
2. Battery backed RAM read/write (31 bytes)
3. Power save mode manipulation (start/stop clock)
4. Trickle charger setup
5. Burst mode read/write
6. 24 hour format only (12 hour format is function Time library)

Whether used with the DS1302, the user is responsible for ensuring reads and writes do not exceed the device's address space (0x80-0x90 for DS1302 clock data and 0xC0-0xFC RAM data); no bounds checking is done by this library.

The DS1302 uses a 3-wire interface:

It is not I2C, not OneWire, and not SPI. So the standard libraries can not be used.

The "Chip Enable" pin was called "/Reset" before.

The chip has internal pull-down registers. This keeps the chip disabled, even if the pins of the Arduino are floating.

In burst mode, all the clock data is read at once. This is to prevent a rollover of a digit during reading. The read data is from an internal buffer.

The DS1302 has 31 of ram, which can be used to store data. The contents will be lost if the Arduino is off, and the backup battery gets empty. It is better to store data in the EEPROM of the Arduino.

The DS1302 has a build-in trickle charger. That can be used for example with a rechargeble battery or a supercap.

Library(คลิ๊ก)