Selecting a memory type for small, occasional read/write updates — which technology is typically used when only a small amount of non-volatile read/write storage is required?

Introduction / Context:
Designers often need to store configuration parameters, calibration constants, or user settings that must persist without power yet be updateable occasionally in the field. The memory choice must balance non-volatility, endurance, write granularity, interface simplicity, and cost.

Given Data / Assumptions:

• Requirement: small amount of read/write storage with non-volatile retention.
• Updates are occasional, not continuous high-throughput logging.
• Low pin count and in-circuit programmability are preferred.

Concept / Approach:
EEPROM (Electrically Erasable PROM) allows byte/page-level electrical erase and write in-circuit, with typical endurance ratings from tens of thousands to millions of cycles per location and data retention for years. PROM and Mask ROM are one-time or factory programmed (not rewriteable). SRAM and DRAM are volatile; they lose content without power and therefore do not meet the non-volatile requirement for persistent settings without a battery.

Step-by-Step Solution:

Verification / Alternative check:
Microcontroller reference designs commonly pair EEPROM for parameter storage or emulate EEPROM in Flash when no discrete EEPROM is used, underscoring its role for small, occasional updates.

Why Other Options Are Wrong:

Common Pitfalls:
Confusing EEPROM with EPROM; assuming Flash always suits tiny updates—Flash typically erases in blocks, making EEPROM more convenient for small records.

Final Answer:
EEPROMs