16Kbit SPI EEPROM for parameter storage
The Microchip 25LC160C-I/P is a 16Kbit serial EEPROM with an SPI interface, organized as 2K x 8 bits. The through-hole 8-PDIP package suits breadboard prototyping, legacy board retrofits, and environments where socketed memory simplifies field updates.
10 MHz SPI — bus margin matters
At 10 MHz the SPI bus timing is tight enough that trace length and capacitive loading on the SCK and MISO lines matter. For a 5V rail the input thresholds are TTL-compatible; at 2.5V the VIH floor is 0.7 x VCC, so a 1.8V-logic master needs a level shifter. The write cycle time is 5 ms per page or byte — factor that into the firmware's write-polling loop so it doesn't busy-wait past the timeout.