4 Kbit serial EEPROM for configuration and calibration storage
The STMicroelectronics M24C04-FMN6TP is a 4 Kbit serial EEPROM organized as 512 x 8 bits, accessed through an I²C interface operating up to 400 kHz. It stores non-volatile data such as calibration coefficients, serial presence detect tables, or small firmware configuration blocks.
Read access time is 900 ns per byte, which is the time from the I²C address byte to the first data byte appearing on SDA. At 400 kHz the bus runs 2.5 µs per bit, so the access fits within the first data byte transfer — no extra wait states for most MCU I²C peripherals. The write cycle time of 5 ms (word or page) is the period after a STOP condition during which the EEPROM performs its internal programming. Firmware must either poll the acknowledge bit (the device NAKs until programming completes) or insert a 5 ms delay before the next write command. This 5 ms window matters when writing calibration tables at power-up: a 512-byte page write takes 5 ms, but writing 512 bytes one byte at a time would take 512 × 5 ms = 2.56 seconds.
The 1.7 V minimum supply is low enough to run from a single Li-ion cell near end-of-discharge (2.8 V) or a 1.8 V rail, while the 5.5 V maximum allows direct connection to legacy 5 V buses.