EM78P458/459 OTP ROM is an 8-bit single-chip microcomputer using low power, high-speed CMOS process. It has a 4k*13-bit ROM (OTP-ROM) that can be burned once. Therefore, users can easily improve and perfect the program. The program code can be written into the chip using an EMC programmer.
The EM78P458 and EM78P459 are low‑power 8‑bit microcontrollers fabricated with a high‑speed CMOS process. They integrate a 4 K × 13‑bit one‑time‑programmable ROM, 84 × 8‑bit SRAM, two bidirectional I/O ports, an 8‑level stack, a real‑time timer/counter, an 8‑bit ADC and two PWM generators.
The document provides detailed pin assignments, functional block diagrams, register maps, and electrical specifications such as operating voltage, temperature ranges, current consumption, and recommended crystal/ceramic resonator values. Package options include 20‑pin DIP/SOP and 24‑pin skinny‑DIP/SOP variants. This manual is written in Chinese.
| Operating voltage range | 2.3 V ~ 5.5 V |
|---|---|
| Operating temperature range (civilian) | 0 °C ~ 70 °C |
| Operating temperature range (industrial) | -40 °C ~ 85 °C |
| Internal OTP ROM size | 4 K × 13 bits |
| Internal SRAM size | 84 × 8 bits |
| Number of I/O ports | 2 bidirectional ports |
| Timer/Counter (TCC) resolution | 8 bits |
| ADC resolution | 8 bits |
| PWM resolution | 10 bits |
| Typical supply current @3 V/32 kHz | 15 µA |
| Sleep mode current | 1 µA |
The device operates from 2.3 V to 5.5 V.
It provides two bidirectional I/O ports.
The OTP ROM is 4 K × 13 bits.
Typical sleep‑mode current is about 1 µA.