Microchip Technology MEC1406-NU

Overview

MEC1406-NU from Microchip Technology is a 32-bit ACPI-compliant embedded controller (EC) for notebook and tablet platforms, integrating a MIPS32 M14K™ core, 160 kB code-optimized SRAM, LPC host interface, 106 GPIOs, and full 8042 keyboard controller emulation. It operates at 3.3 V, supports Connected Standby, and delivers real-time power management via VTR/VBAT power planes and a 32 kHz RTC/Week Timer - deployed in OEM laptop EC subsystems for system boot control, thermal monitoring, and keyboard/mouse interface.

For engineers reviewing the MEC1406-NU datasheet, MEC1406-NU pinout, MEC1406-NU application, or MEC1406-NU equivalent, key selection criteria include LPC interface timing compliance (19.2–33 MHz), battery-backed 64 B SRAM retention, eSPI readiness (though not enabled by default on this variant), and firmware-configurable GPIO power-well emulation for suspend-state I/O control.

Technical Context

The MEC1406-NU implements a tightly coupled MIPS32 M14K microcontroller core with microMIPS instruction set support, programmable clock frequencies (1/3/12/48 MHz), and hardware debug features including 6 breakpoints and Trace FIFO Debug Port (TFDP). Its interrupt architecture combines a vectored JTVIC with maskable wake-up sources across sleep states.

Power management is implemented through dual standby rails (VTR and VBAT), integrated standby power reset generator, and multiple low-power timers - including a 32-bit RTOS timer running continuously off the 32 kHz source in all chip sleep states except JTAG halt, plus hibernation and week timers with sub-second alarm resolution and system power presence detection.

Key Specifications

Pinout & Package

MEC1406-NU is housed in a 128-pin VTQFP RoHS-compliant package (14 × 14 mm, 0.4 mm pitch), with pin functions defined per Microchip DS00001956E Section 2.0. Pin assignments are firmware-configurable via GPIO control registers, supporting multiplexed alternate functions including LPC, PS/2, SMBus, SPI, UART, and BC-Link.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar embedded controller applications.

Compared with MEC1404-NU, MEC1406-NU provides 32 kB additional code SRAM for more complex thermal/power policies; compared with MEC1416-NU, it lacks eSPI support but offers identical LPC performance and lower BOM cost in legacy designs.

Availability

MEC1406-NU is available at Aetrix Electronics and suitable for laptop EC subsystems, notebook power management systems, and thermal control modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MEC1406-NU includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Microchip Technology Inc. is a leading provider of microcontrollers, analog, FPGA, and connectivity solutions, serving automotive, industrial, consumer, and computing markets with secure, reliable silicon and development tools.

The MEC140x family is designed specifically for PC-class embedded controller roles - delivering ACPI-compliant power management, keyboard/mouse interface, and system monitoring in space-constrained notebook and 2-in-1 platforms.

FAQ

What host interface protocols does the MEC1406-NU support?

The MEC1406-NU supports LPC (Low Pin Count) and I²C host interfaces as specified in its product configuration. It does not include eSPI functionality - that is reserved for the MEC141x series (e.g., MEC1416-NU). The LPC interface complies with Specification 1.1 and supports 19.2–33 MHz bus clocks, SERIRQ, SMI#, and EC_SCI# signals. I²C operation requires firmware configuration of SMBus controllers and is limited to systems where VTR_33_18 is routed to 1.8 V.

Does the MEC1406-NU include battery-backed memory, and what is its retention capability?

Yes, the MEC1406-NU includes 64 bytes of battery-powered SRAM that remains active and retains data when only VBAT is supplied - such as during system suspend-to-RAM (S3) or complete power-off (S5) states. This memory is accessible via the VBAT register bank and is commonly used to store critical system state, last-boot timestamp, or battery health parameters without requiring host intervention or external backup components.

How many PWM outputs and tachometer inputs does the MEC1406-NU provide?

The MEC1406-NU provides up to eight programmable PWM outputs and two dedicated fan tachometer (TACH) inputs. Each PWM channel supports 16-bit ON and OFF counters for precise duty-cycle control, while each TACH input delivers 16-bit resolution for accurate RPM measurement - enabling closed-loop fan speed regulation directly within the EC firmware without host CPU involvement.

Is the MEC1406-NU pin-compatible with other devices in the MEC140x family?

Yes, the MEC1406-NU in the 128-VTQFP package shares identical pinout and footprint with MEC1404-NU and MEC1408-NU. All three support the same LPC/I²C host interface mapping, GPIO assignment, and peripheral signal routing. Firmware and PCB layout can be reused across these variants, differing only in internal SRAM capacity (128/160/192 kB) and minor feature enablement - simplifying platform scaling and BOM rationalization.

What debug interfaces are available on the MEC1406-NU for firmware development?

The MEC1406-NU provides four debug interfaces: a 2-wire ICSP/JTAG port for in-circuit programming and breakpoint debugging; a Trace FIFO Debug Port (TFDP) for real-time instruction trace; a Port 80 BIOS Debug Port with 24-bit timestamp and 16-entry FIFO; and a full NS16C550A-compatible UART accessible from both host and EC. These interfaces collectively support firmware bring-up, timing analysis, and field diagnostics without requiring external debug probes beyond standard USB-to-serial adapters.