What is it? This is a breakout board for the PCA21125 SPI RTCC IC. It breaks out the SPI pins, power input, interrupt and clockout pins. The board also includes an onboard CR2032 battery holder. It comes with a dual row connector, allowing one connector to be used for probing while the other can be connected to a signal. If you need it soldered, please send me a message.

The PCA21125 is a Real-Time Clock and Calendar IC from NXP. It uses SPI for communication, with a maximum data rate of 6 Mbit/s. The IC can be used to set alarms, includes timer functions and has interrupt capability (open-drain). It also includes an integrated oscillator capacitor/The design uses a highly accurate 32.768kHz crystal for time keeping. The crystal has a frequency tolerance of +/- 20ppm. All components used are able to be used with an operating temperature range of -40 degC to + 85 degC.

The IC has an operating voltage range of 1.8 to 5.5V, so it is ideal for both 3.3V and 5V systems.

Although the IC itself does not include a backup battery, the design includes a CR2032 backup battery with reverse polarity diodes to protect it from getting discharged by the system. This battery allows the IC to still operate and keep time without an external power supply input.

Designed and made in the USA!

Why did you make it? I made this breakout board because I need an option for a SPI based RTCC IC that has interrupt and clockout features.