| Features |
| PCF2123 / PCA2125 Low Power SPI based RTC |
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Resolution - sec, minutes, hours, weekday, day, month, year |
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Operating voltage 1.2 to 5.5V |
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Low standby current for SuperCap |
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Three-line SPI with separate data I/O |
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Programmable timer / alarm functions with interrupt capability |
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Internal power-on reset |
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32.768 KHz quartz crystal |
| LM75B Low Power Temp Sensor |
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Temperature resolution of 0.125 °C |
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Pin-for-Pin Replacement for LM75 and LM75A standards |
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Temperatures range from -55 °C to +125 °C |
P89LPC932A1 8-bit, 2-clock, 80C51 MCU |
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8 KB Flash, 256 bytes RAM |
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28-pin PLCC package with Internal RC Oscillator |
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UART, ADC, DAC, two 16-bit timers & RTC, KBI |
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WDT with on chip 400kHz oscillator |
The NXP RTC Demo PCF2123 is a reference design for a low power Real Time Clock and LCD
solution with an available I2C temperature sensor. The Demo Board is controlled by a simple two-button user interface (MODE and SELECT). Example code for several sample applications: a programmable time and date display, a programmable countdown timer, and a repeating pattern of text lines, can all be found on the 
