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PCF2128 Datasheet(PDF) 1 Page - NXP Semiconductors |
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PCF2128 Datasheet(HTML) 1 Page - NXP Semiconductors |
1 / 10 page ![]() 1. General description The PCF2128 is a ready to run CMOS real time clock/calendar with an integrated temperature compensated crystal oscillator (TCXO). In timekeeping applications the high accuracy of the PCF2128 allows it to be used as a replacement for costly and higher powered long wave receivers or GPS receivers. A programmable battery switch-over circuit enables an uninterruptible power supply and consequently continuous timekeeping. The PCF2128 additionally features 512 bytes of general purpose RAM, a programmable watchdog, a time stamp facility and a voltage monitoring facility. Programming is possible using either an SPI or an I2C-bus interface. 2. Features PCF2128 Integrated RTC / TCXO / Crystal Rev. 00.03 — 4 June 2007 Preliminary [short] data sheet Integration of a 32.768 kHz quartz crystal in the same package as the RTC 512 bytes of general purpose static RAM temperature compensated crystal oscillator (TCXO) with integrated capacitors. 1 second or 1 minute interrupt output accuracy: typically 3 ppm from −20 °C to +70 °C, typically 5 ppm from −40 °C to +85 °C oscillator stop detection provides year, month, day, weekday, hours, minutes and seconds two line bi-directional 1 MHz fast mode plus I2C interface programmable alarm function with interrupt capability timestamp input programmable countdown timer with interrupt capability power-on reset programmable watchdog timer with interrupt and reset capability 3 line SPI interface with separate data input and output (maximum speed 6.5 Mbits/s) timestamp function with interrupt capability programmable square wave output pin battery backup input pin and switch-over circuitry I2C-bus slave address: read A3H and write A2H extra power fail detection with input and output pins clock operating voltage: <tbd> to 5.5 V battery low detection low backup current; typical 0.95 μA at VDD = 3.0 V and Tamb =25 °C battery backed output voltage pin selectable I2C and SPI interface |