# NEC μPD7901G

> System-on-a-chip introduced by NEC in 1981

**Wikidata**: [Q136366985](https://www.wikidata.org/wiki/Q136366985)  
**Source**: https://4ort.xyz/entity/nec-pd7901g

## Summary
The NEC μPD7901G is a system-on-a-chip (SoC) microcontroller introduced by NEC in 1981. It integrated a BASIC interpreter, 5 KB of ROM, and 128 bytes of RAM on a single chip, enabling compact designs like pocket computers and industrial devices. Its low-power complementary-MOS design simplified software development for portable and embedded applications.

## Key Facts
- Introduced by NEC in **1981** as a system-on-a-chip microcontroller.
- Featured a **5 KB ROM** with a built-in BASIC interpreter and **128 bytes of RAM**.
- Operated at low power consumption due to complementary-MOS technology.
- Used in the **Sanyo PHC-10** pocket computer (1982) and industrial applications.
- Directly interfaced with keyboards and supported external LCD controllers and memory.
- Aliases: μPD7901G, PD7901G.
- Classified as a microcontroller (small computer on a single integrated circuit).

## FAQs
### Q: When was the NEC μPD7901G released?
A: The NEC μPD7901G was introduced by NEC in 1981.

### Q: What was the NEC μPD7901G used for?
A: It was used in devices like the Sanyo PHC-10 pocket computer and industrial systems due to its low-power design and ease of software development.

### Q: What made the NEC μPD7901G unique?
A: It included a BASIC interpreter in ROM, enabling programmability in a compact, low-power package, and supported direct keyboard and LCD integration.

## Why It Matters
The NEC μPD7901G played a significant role in advancing portable and embedded computing in the early 1980s. By integrating a BASIC interpreter, ROM, and RAM on a single chip, it streamlined the development of pocket computers like the Sanyo PHC-10 and simplified industrial automation. Its low-power COMOS design addressed energy efficiency challenges, while its modular architecture allowed customization for keyboards, LCDs, and external memory. This combination of features reduced hardware complexity and costs, democratizing access to programmable devices and influencing the evolution of microcontrollers for consumer and industrial markets.

## Notable For
- **Integrated BASIC interpreter**: Enabled out-of-the-box programmability in a minimal footprint.
- **Low-power COMOS technology**: Suited for battery-operated devices like pocket computers.
- **Modular design**: Supported expansion with LCD controllers and external memory for tailored applications.
- **Versatility**: Applied in both consumer electronics (e.g., Sanyo PHC-10) and industrial systems.

## Body
### Technical Specifications
- **Processor**: Low-power complementary-MOS microcomputer.
- **Memory**: 5 KB ROM (containing BASIC interpreter), 128 bytes RAM.
- **Power**: Optimized for low energy consumption.
- **Interfaces**: Direct keyboard connectivity, compatible with LCD controllers.

### Applications
- **Consumer**: Powered the Sanyo PHC-10 (1982), one of the earliest pocket computers.
- **Industrial**: Used in automated systems due to ease of software development and reliability.

### Design and Features
- **Single-chip integration**: Combined CPU, memory, and BASIC interpreter for compact designs.
- **Expandability**: Allowed addition of external memory and LCDs for customized devices.
- **Development ease**: BASIC interpreter lowered the barrier for creating applications.

## References

1. [1981](https://web.archive.org/web/20250823182730/https://www.worldradiohistory.com/Archive-Electronics/80s/81/Electronics-1981-10-20.pdf)
2. [1982](https://archive.org/details/Io19826/page/n367/mode/2up)