# ENE KB3700

> Embedded controller

**Wikidata**: [Q66892573](https://www.wikidata.org/wiki/Q66892573)  
**Source**: https://4ort.xyz/entity/ene-kb3700

## Summary
ENE KB3700 is an embedded-controller chip manufactured by ENE Technology that handles low-level system tasks in laptops and other computers. As a member of the embedded-controller class, it offloads keyboard scanning, battery management, thermal control, and power sequencing from the main CPU so the operating system does not have to perform them.

## Key Facts
- Manufacturer: ENE Technology Inc. (Taiwan)
- Part number: KB3700
- Device class: embedded controller (EC)
- Public datasheet: KB3700-ds-01.pdf, archived 31 Aug 2019
- Wikidata item: Q115792636
- Aliases commonly used in firmware source: KB3700

## FAQs
### Q: What does the ENE KB3700 actually do inside a laptop?
A: It is a dedicated 8-bit microcontroller that constantly monitors the keyboard matrix, fan tachometers, battery voltage, and temperature sensors. When you press a key or the battery runs low, the KB3700—not the main CPU—first detects the event and then wakes or notifies the operating system.

### Q: Is the KB3700 unique to one brand or model?
A: No. ENE markets the chip to multiple laptop OEMs, so you can find KB3700 (or its firmware-compatible variants) in machines from several manufacturers, especially budget and education-focused notebooks.

### Q: Where can I find the official datasheet?
A: ENE hosts the PDF “KB3700-ds-01.pdf” on its public wiki; a snapshot is archived at http://wiki.laptop.org/images/a/ab/KB3700-ds-01.pdf (retrieved 2019-08-31).

## Why It Matters
Embedded controllers are the unsung managers of modern portable computers. The KB3700 gives laptop makers a single-chip solution that replaces multiple smaller ICs, shrinking board space and cutting cost while meeting the ACPI (Advanced Configuration & Power Interface) specification. Because it operates as soon as power is available—even before the CPU boots—it also implements critical safety interlocks: it keeps batteries from over-charging, prevents thermal runaway, and ensures fans spin before heat builds up. For open-hardware initiatives such as One Laptop per Child, the availability of a public datasheet for the KB3700 allowed firmware developers to write open-source EC code, increasing transparency and security for education markets that demand auditability.

## Notable For
- One of the few embedded controllers whose datasheet ENE has released publicly, aiding open-source firmware projects
- Integrates keyboard scanner, ADC, PWM fan control, and SMBus battery interface in one 8-bit MCU, reducing BOM count
- Firmware-upgradable via vendor-provided tools, letting OEMs add new hot-key combinations or battery algorithms without a hardware spin
- Widely used reference design in low-cost education laptops during the 2010s

## Body
### Device Role
The KB3700 sits on the laptop’s mainboard and communicates with the host chipset over the LPC (Low Pin Count) bus. It remains powered when the system is off, drawing only micro-amps from the standby rail so it can detect the power-button press and sequence the main rails.

### Functional Blocks
- Keyboard matrix scanner supporting up to 18 × 8 keys
- 8-channel, 10-bit ADC for battery voltage, current, and temperature
- Fan-control PWM outputs with tachometer inputs
- SMBus master for smart-battery and charger communication
- GPIOs for lid switch, docking detect, and LED indicators

### Firmware & Interface
ENE supplies a 32 kB mask-ROM bootloader plus 32 kB of on-chip flash for customer firmware. OEMs typically implement the ACPI Embedded Controller Interface so the OS can query battery capacity or set fan duty via standard EC commands. Updates are delivered as encrypted binaries through the vendor’s Windows utility or, in open-source projects, by flashing the chip’s SPI-linked external EEPROM.

### Power & Packaging
Packaged in a 48-pin QFN (7 mm × 7 mm) or 64-pin LQFP, the part runs from 3.3 V and offers industrial temperature range (-40 °C to +85 °C) for rugged designs.