EM78P451 OTP ROM is a member of EM78P451 series products, based on low-power, high-speed CMOS technology design and development. Its operational kernel is implemented with RISC structure, providing mask ROM and OTP two versions, with flexibility and cost advantages. EM78P451 OTP ROM supports SPI function and RS-232 interface, suitable for wired communication applications.
The EM78P451 is a low‑power 8‑bit microcontroller with a mask‑ROM version and one‑time programmable (OTP) option. It features a RISC‑like core, SPI interface, and optional RS‑232, making it suitable for wired communication and engineering test stages.
The document provides a complete functional block diagram, pin assignment table, register descriptions, and application circuit examples, along with package information for both DIP and QFP variants.
| Operating voltage range | 2.3 V ~ 5.5 V |
|---|---|
| Operating temperature range | 0 °C ~ 70 °C |
| Crystal mode frequency (5 V) | up to 20 MHz |
| RC mode frequency (5 V) | up to 4 MHz |
| Active current consumption | < 3 mA at 5 V/4 MHz |
| Sleep mode current | ≈ 10 nA |
| On‑chip ROM | 4 K × 13 bits |
| General‑purpose registers | 140 × 8 bits |
| I/O ports | 5 bi‑directional ports (35 pins) |
| LED pins | 3 direct‑driving pins with internal resistors |
| Package options | 40‑pin DIP 600 mil, 44‑pin QFP |
Four interrupt types: external interrupt, SPI transmission completed interrupt, TCC overflow interrupt, and Timer1 comparator match interrupt.
The device contains 4 K × 13 bits of ROM.
It provides 35 I/O pins organized into five bi‑directional ports.