Electronic – Parallel EEPROM write to with I2C


I was wondering if there is a hybrid between the serial and parallel EEPROM's? What I mean is, is there an EEPROM that can be written to over I2C and then once it is setup can be controlled with some hardware Address pins, like how parallel EEPROM's change there output pin states when their address pins change.

Just some background, I am, for fun, building a little 4 x 7 segment led display. I wanted to just have the arduino send the current time once a minute to the eeprom over I2C, where then an external clock and counter change the eeproms addresses to multiplex the display.

Best Answer

I'm not aware of any parts that support this feature.

Parallel EEPROMs are generally considered a "legacy" part nowadays. They're all older designs, typically with 5V I/O, and they haven't changed significantly in decades. There's never been any serious consideration of adding more modern features like I2C access; these parts are all aimed at use in ancient systems designed long before I2C was in common use.

Besides, EEPROMs are primarily intended for "write-once" applications. While they can be rewritten, they have a limited number of write cycles -- 10k - 100k is typical. Even at one write per minute, you'd burn through that in weeks or months.

Consider using an LED driver like the MAX7219 / MAX7221 instead. They're made explicitly for this application -- they'll handle everything, including current control, multiplexing, and even have a character table built in -- and they can be controlled over SPI.