The 128 pins of the LQFP package are clustered into specialized hardware subsystems: Pin Subsystem Group Primary Functions & Signals Description VCC , VSTBY , AVCC , GND Direct power supply connection pins. They distribute standby power and analog filtering blocks. System Bus Interface LAD[3:0] , LFRAME# , SERIRQ
The EC monitors temperature sensors across the laptop (e.g., CPU, GPU, and ambient sensors) and controls fan speeds to maintain optimal thermal conditions. C. Keyboard and Peripheral Controller
The "-128" suffix in its name is significant, as it denotes . This onboard memory stores the chip's firmware (often referred to as EC BIOS). The fact that this is programmable memory is crucial for manufacturers, as it allows them to update the EC's behavior for power management or address hardware bugs via a firmware update without replacing the physical component.
While it may sometimes auto-sync from the main BIOS, it often requires manual programming via the I2C or keyboard connector interface to initiate the system cycle. it8995e 128 datasheet
The chip provides which can be individually configured as inputs or outputs via software. In a laptop, these are used for tasks such as reading the lid switch state, controlling LEDs, or interfacing with simple sensors.
Supports various system wake-up functions for power management. Technical Details Manufacturer ITE Tech. Inc. Interface Typically interfaces via LPC or eSPI bus Operating Voltage Generally supports 1.8V / 3.3V logic (standard for ITE ECs) Programmability
Furthermore, the datasheet dedicates significant real estate to environmental monitoring and fan control. In the voltage regulation section, one finds precise specifications for monitoring the +12V, +5V, Vcore, and Vbat rails. The IT8995E contains an Analog-to-Digital Converter (ADC) that constantly samples these voltages, looking for dangerous droops or spikes. Simultaneously, its hardware monitoring block reads thermistor inputs and tachometer signals from fans. By adjusting Pulse Width Modulation (PWM) duty cycles, the chip controls cooling without interrupting the main CPU. This is a masterclass in efficient system design; the datasheet shows that the IT8995E handles the “housekeeping” autonomously, ensuring thermal stability while the main processor focuses on computation. The 128 pins of the LQFP package are
It acts as the primary hardware interface for the built-in matrix keyboard and standard SPI/I2C-based touchpads. The chip converts matrix coordinate key-presses into standard PS/2 or HID input scan codes passed over the Low Pin Count (LPC) or eSPI bus directly to the processor. 4. Battery and Charging Supervision
(Recreate schematic from datasheet showing:)
According to manufacturing design layouts, the chip features strict industrial-grade protection profiles: The fact that this is programmable memory is
3.3V Standby Power. This rail must be active as soon as the power adapter is plugged in.
LQFP-128 (Low Profile Quad Flat Package) with 128 pins