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Topic: 28C256 28C512 parallel eeproms (Read 2135 times) previous topic - next topic

marioR

I'm so sorry to post about something obvious.

However, after doing several searches, including reading several posts about interfacing with eproms, I have yet to find a solution.

I'm currently trying to read/write to a AT28C256 eeprom and have not found much documentation. I seem to find many posts about Ic2 eeproms and SPI eeproms, but not parallel eeproms.

Can any one steer me to the right direction.

Thank you so much

Mario

johnwasser

You need a LOT of pins to control the 15 address pins, 8 data pins and the various control pins.  That is why I2C and SPI EEPROMs are much more popular on Arduino.  Download the data sheet to see how to address, read, and write to the chip.  You can use shift registers for the address lines and a universal shift register for the data lines.  That should make it possible to use the chip without needing a Mega for the extra pins.
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marioR

Thank you for your quick reply John.

Do you know of a project that has already accomplished this feat? I don't want to reinvent the wheel for something that I'm sure has been done before.

These parallel eeproms are old technology

johnwasser

Someone recently tried hooking up a static RAM chip to an Arduino with some shift registers.  I don't know if anyone has done it with an EEPROM.
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