EM78P458/459 OTP ROM is a 8-bit microprocessor designed and developed by EM Microsystems with low-power and high-speed CMOS technology. It is equipped with a 4K*13-bit Electrical One Time Programmable Read Only Memory (OTP-ROM). With its OTP-ROM feature, it is able to offer a convenient way of developing and verifying user’ s programs. Moreover, user can take advantage of EMC Writer to easily program his development code.
This document describes the ELAN EM78P458 and EM78P459 8‑bit microcontrollers with an integrated 4K×13‑bit OTP ROM. It lists electrical characteristics, operating ranges, package options, and the internal register set.
The datasheet includes pin‑assignment tables, functional block diagrams, and detailed information on the CPU core, timers, ADC, PWM, watchdog, and power‑down features, useful for hardware designers and firmware developers.
| Operating voltage range | 2.3 V ~ 5.5 V |
|---|---|
| Operating temperature range (commercial) | 0 °C ~ 70 °C |
| Operating temperature range (industrial) | -40 °C ~ 85 °C |
| Power consumption at 5 V/4 MHz | < 1.5 mA |
| On‑chip OTP ROM size | 4 K × 13 bits |
| On‑chip SRAM registers | 84 × 8 bits |
| Number of bi‑directional I/O ports | 2 |
| Package pin count (EM78P458AP) | 20 pins |
| Reset pulse width (25 °C) | 2000 ns |
The device operates from 2.3 V up to 5.5 V.
The EM78P458AP comes in a 20‑pin DIP package.
The /RESET pulse width is specified as 2000 ns at 25 °C.
Typical current consumption is less than 1.5 mA.