NXP Semiconductors MC9S12XET256MAG

Overview

MC9S12XET256MAG from NXP (formerly Freescale) is a 16-bit HCS12X microcontroller featuring a 256 KB on-chip flash memory, 14 KB RAM, and an XGATE co-processor for offloading real-time tasks. It operates at up to 50 MHz, supports CAN 2.0B and LIN 2.1 protocols, and integrates dual 12-bit ADCs (16-channel), 8-channel PWM, and enhanced capture timer modules. It is used in automotive body control modules requiring deterministic interrupt response and functional safety support.

For engineers reviewing the MC9S12XET256MAG datasheet, MC9S12XET256MAG pinout, MC9S12XET256MAG application, or MC9S12XET256MAG equivalent, this page delivers verified technical context, package mapping, pin-level circuit roles, validated alternatives, and design-meaningful specifications - all grounded in the official MC9S12XE Family Reference Manual Rev. 1.25 and Freescale/NXP ordering documentation.

Technical Context

The MC9S12XET256MAG implements the S12X CPU core with 16-bit data/24-bit address bus, augmented by the XGATE RISC co-processor that handles time-critical I/O servicing-including CAN message filtering, ADC sequencing, and PWM synchronization-without CPU intervention. Its memory architecture includes banked flash with EEPROM emulation, protected RAM regions, and configurable wait-state logic for external bus interfacing.

It integrates dual MSCAN modules compliant with ISO 11898-1, two independent 12-bit ADCs with hardware-triggered conversion sequences, and a flexible port integration module supporting GPIO, interrupt-on-change, and peripheral routing via MODRR registers. Clock generation uses a PLL-based system with multiple internal/external sources including crystal, RC, and BDM clock inputs.

Key Specifications

Pinout & Package

MC9S12XET256MAG is housed in a 112-pin LQFP package (16 × 16 mm, 0.4 mm pitch), optimized for automotive PCB layouts with dedicated power/ground pin distribution and noise-suppressed analog sections.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 16-bit automotive microcontroller applications.

Compared with MC9S12XET256MAG, MC9S12XEP100MAL trades memory and XGATE capability for lower unit cost, while S912XEQ512J2MAG offers scalable flash/RAM with identical footprint and enhanced robustness-making it ideal for next-generation derivatives.

Availability

MC9S12XET256MAG is available at Aetrix Electronics and suitable for automotive body control modules, industrial motor drives, commercial vehicle telematics gateways, and off-highway equipment monitors requiring stable component supply across extended product lifecycles.

Supply support for MC9S12XET256MAG 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

NXP Semiconductors is a global leader in secure connectivity solutions for automotive, industrial, and IoT applications, formed from the spin-off of Freescale Semiconductor in 2015.

The MC9S12XET256MAG belongs to the S12XE family-designed specifically for cost-sensitive, safety-aware automotive applications requiring deterministic real-time performance, CAN/LIN connectivity, and robust operation in harsh environments.

FAQ

What is the maximum operating frequency of the MC9S12XET256MAG?

The MC9S12XET256MAG achieves a maximum core frequency of 50 MHz using its on-chip PLL, which accepts input clocks from 1–8 MHz crystal or internal RC sources. This frequency enables deterministic execution of time-critical automotive tasks such as CAN message processing and PWM waveform generation. The MC9S12XET256MAG's timing budget supports sub-microsecond interrupt latency and consistent instruction throughput across voltage and temperature ranges.

Does the MC9S12XET256MAG support CAN FD?

No, the MC9S12XET256MAG supports only classical CAN 2.0B (ISO 11898-1) at up to 1 Mbps. It does not implement CAN FD features such as flexible data-rate, extended data length, or CRC enhancements. Its dual MSCAN modules are fully compatible with legacy J1939 and CANopen networks but require external CAN FD controllers for migration to higher-bandwidth protocols. The MC9S12XET256MAG remains widely deployed in systems where classical CAN meets bandwidth and timing requirements.

How is the XGATE co-processor used in the MC9S12XET256MAG?

The XGATE co-processor in the MC9S12XET256MAG executes autonomous I/O service routines-including CAN message filtering, ADC conversion triggering, and PWM synchronization-without CPU involvement. It accesses dedicated RAM and peripherals via its own bus matrix, reducing main CPU load and eliminating context-switch latency. In the MC9S12XET256MAG, XGATE is commonly configured to handle time-critical background tasks like periodic sensor polling or fault detection, freeing the S12X core for application logic.

What package type and pin count does the MC9S12XET256MAG use?

The MC9S12XET256MAG is packaged in a 112-pin LQFP (16 × 16 mm, 0.4 mm pitch) with exposed thermal pad, specified in Freescale's Package Information Appendix B. This package provides balanced I/O density, thermal performance, and manufacturability for automotive PCB assemblies. Pin assignments include dedicated analog power domains, isolated reset and clock inputs, and grouped CAN/SCI/SPI signal pairs to minimize crosstalk. The MC9S12XET256MAG's pinout is shared across the S12XE family, enabling layout reuse across memory variants.

Is the MC9S12XET256MAG qualified for automotive applications?

Yes, the MC9S12XET256MAG is AEC-Q100 Grade 2 qualified (−40°C to +105°C) and designed for automotive body electronics, chassis, and powertrain subsystems. It includes built-in features supporting functional safety development-such as memory protection unit (MPU), clock monitor, and fail-safe reset behavior-as documented in the S12XE Family Reference Manual. While not ASIL-certified out-of-box, the MC9S12XET256MAG serves as a foundation for ASIL-B software implementations in production ECUs.