Non-Volatile Memory for the Olduino/Z
To be useful as an embedded computer like the Arduino, an Olduino needs to be able to retain its programming with the power off. The 1802 olduino uses STK16C88 nonvolatile SRAM from cypress semiconductors. These are expensive chips that use a “quantum trap” to preserve memory contents.
They’re no longer made but i have a couple so i put one in this morning and it works fine. All I see at digikey now are even more expensive battery backed modules so i’m hoping i can find a few more of the cypress chips somewhere reasonable.