NXP Semiconductors MC908KX2MDWE

Overview

MC908KX2MDWE from Freescale Semiconductor is an 8-bit HCS08-core microcontroller with 2 KB on-chip FLASH, 128 B RAM, and integrated 8-channel 8-bit ADC. It features a programmable internal clock generator (ICG), keyboard interrupt module (KBI), low-voltage inhibit (LVI), and external IRQ1 pin with 19–43 kΩ pullup. Designed for cost-sensitive industrial control and appliance interfaces.

For engineers reviewing the MC908KX2MDWE datasheet, MC908KX2MDWE pinout, MC908KX2MDWE application, or MC908KX2MDWE equivalent, this page delivers verified electrical specs, SOIC-28 package mapping, ICG trim register behavior, KBI scan timing, and direct alternatives for legacy HCS08-based designs requiring drop-in replacement or migration path.

Technical Context

The MC908KX2MDWE implements the HCS08 CPU core with 2 KB of SuperFlash® memory, supporting in-system programming and page erase. Its ICG includes a digitally controlled oscillator (DCO) with trimmable frequency, modulo-N divider, and clock monitor circuitry for fail-safe operation.

It integrates an 8-channel single-ended ADC with configurable conversion time (16–64 µs), keyboard interrupt module with debounced scanning logic, and dual-voltage LVI with selectable trip points (4.0 V or 4.5 V). All peripherals are synchronized to the internal bus clock derived from the ICG output.

Key Specifications

Pinout & Package

MC908KX2MDWE is housed in a 28-pin SOIC (Small Outline Integrated Circuit) package with 0.300-inch body width and standard 1.27 mm pitch. Pin assignments follow Freescale's MC68HC908KX2 pinout layout per Data Sheet Rev. 2.1, Appendix A.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC908KX2MDWE, MC908KX8MDWE offers immediate memory headroom within the same footprint, while S9KEAZ128AMLH provides architectural modernization at the cost of layout change - both serve distinct stages of product lifecycle planning.

Availability

MC908KX2MDWE is available at Aetrix Electronics and suitable for industrial sensor interfaces, home appliance control panels, and smart power outlet designs requiring stable component supply and long-term obsolescence management.

Supply support for MC908KX2MDWE 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

Freescale Semiconductor (now part of NXP Semiconductors) pioneered mixed-signal microcontrollers for automotive and industrial markets, emphasizing robustness, integration, and toolchain maturity.

The MC908KX2MDWE belongs to the HCS08 family, designed specifically for cost-optimized, low-power embedded control in harsh environments where reliability and long-term supply stability are critical.

FAQ

What is the maximum operating frequency of the MC908KX2MDWE?

The MC908KX2MDWE supports a maximum bus frequency of 20 MHz at 5 V supply. This is achieved through its internal clock generator (ICG), which uses a digitally controlled oscillator (DCO) with programmable trim and multiplier registers. The actual achievable frequency depends on VDD, temperature, and ICG configuration - full characterization is provided in Section 7.4.6 of the MC68HC908KX2 datasheet. The MC908KX2MDWE does not require an external crystal to reach this speed.

Does the MC908KX2MDWE support in-system programming (ISP)?

Yes, the MC908KX2MDWE supports in-system programming via its on-chip monitor ROM and SCI interface. Using the built-in bootloader, firmware updates can be performed without removing the device from the board. Programming requires only VDD, VSS, and the SCI TX/RX pins - no special high-voltage signals are needed. The MC908KX2MDWE's SuperFlash® memory enables up to 100,000 erase/write cycles with guaranteed 15-year data retention.

How does the keyboard interrupt module (KBI) function on the MC908KX2MDWE?

The KBI on the MC908KX2MDWE monitors PTA0–PTA4 for transitions and performs automatic debouncing in hardware. When enabled, it scans these lines at a configurable rate (typically every 8–128 µs), detects key presses/releases, and asserts an interrupt request without CPU intervention. This offloads polling tasks and improves real-time responsiveness in human-interface applications. The MC908KX2MDWE's KBI is fully register-configurable and shares no resources with the ADC or TIM modules.

What are the voltage thresholds for the low-voltage inhibit (LVI) on the MC908KX2MDWE?

The MC908KX2MDWE offers two selectable LVI trip points: 4.0 V or 4.5 V nominal, configured via the CONFIG register. Hysteresis is internally fixed at approximately 0.2 V, meaning the release threshold is ~0.2 V above the trip point. For example, with 4.5 V selected, the device resets when VDD falls below 4.5 V and resumes normal operation only after VDD rises above ~4.7 V. This prevents oscillation during slow brownout recovery. The MC908KX2MDWE guarantees correct LVI behavior across its full –40°C to +125°C operating range.

Is the MC908KX2MDWE pin-compatible with other members of the KX series?

Yes, the MC908KX2MDWE is pin-compatible with MC908KX8MDWE and MC68HC08KX8 in the SOIC-28 package. All share identical pin assignments for power, I/O, reset, oscillator, and interrupt signals. Differences lie solely in memory size and minor peripheral enable bits - making the MC908KX2MDWE a direct drop-in option for designs that do not require more than 2 KB FLASH. This compatibility simplifies prototyping and enables scalable memory selection without layout revision.