Microchip’s 25AA/25LC EEPROMs are data storage chips with a simple 3-wire interface. The 25AA/LC is an SPI version of the common 24AA/LC I2C EEPROM.  It comes in capacities of 128bytes to 128kilobytes. We looked at the smallest, the 128byte 25AA010A.
There are Bus Pirate demonstrations for most types of serial EEPROMs. Check out our previous 1-wire (DS2431) and I2C (24LC1025) EEPROM posts.
Continue below to see our test circuit and a demonstration of the 25AA010 EEPROM. We used the Bus Pirate to play with this chip from our PC.  For a limited time you can get your own Bus…

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The PCF8563 is a real-time clock/calendar/alarm chip with an I2C interface. This would be useful in projects where the primary microcontroller doesn’t have enough resources for an interrupt driven clock.
We demonstrate the PCF8563 using the Bus Pirate after the break. For a limited time you can get your own Bus Pirate, fully assembled and shipped worldwide, for only $30.

PCF8563 real-time clock calendar (Octopart search, $1.33). Datasheet (PDF).
The schematic above shows a bare-bones circuit for the PCF8563. It requires a simple external oscillator circuit with a 32.768khz watch crystal (Q1). The oscillator input pin needs an external…

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