NXP Semiconductors MC908KX2MDWER

Overview

MC908KX2MDWER from Freescale Semiconductor is an 8-bit M68HC08 core microcontroller with 2 KB on-chip FLASH, 128 B RAM, 8-channel 8-bit ADC, and integrated keyboard interrupt (KBI) module. It operates at up to 8 MHz internal bus speed, supports 5 V operation, and features low-voltage inhibit (LVI), COP watchdog, and ICG clock generator with DCO and external crystal options. It targets cost-sensitive embedded control in industrial sensors and appliance user interfaces.

For engineers reviewing the MC908KX2MDWER datasheet, MC908KX2MDWER pinout, MC908KX2MDWER application, or MC908KX2MDWER equivalent, this page delivers verified electrical specs, package mapping, functional role in system-level timing and I/O management, and validated alternative parts for design continuity and sourcing resilience.

Technical Context

The MC908KX2MDWER implements the M68HC08 CPU core with Harvard architecture, supporting indexed, direct, and immediate addressing modes. Its Internal Clock Generator (ICG) includes a digitally controlled oscillator (DCO), modulo-N divider, frequency comparator, and digital loop filter - enabling stable internal clock generation without external crystals when required.

It integrates a 8-channel single-ended ADC with programmable conversion time (4–20 µs), keyboard interrupt module with debounced scan logic, and dual interrupt sources (IRQ1 and KBI). The device supports Wait and Stop low-power modes, with LVI reset threshold configurable at 3.8 V or 4.2 V (typical), and features SuperFlash® technology licensed from SST for reliable in-system reprogramming.

Key Specifications

Pinout & Package

MC908KX2MDWER is housed in a 20-pin SOIC (Small Outline Integrated Circuit) package with 300 mil body width, JEDEC MS-013AC compliant, lead-free and RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit microcontroller applications.

Compared with MC908KX2MDWER, MC908KX8CDWE offers 4× more FLASH in identical footprint for seamless firmware growth, while MC9RS08KA2CW trades KBI integration for enhanced analog accuracy - making the former ideal for UI expansion and the latter for sensor-centric designs without keypad needs.

Availability

MC908KX2MDWER is available at Aetrix Electronics and suitable for industrial sensor nodes, home appliance control panels, smart thermostat interfaces, and basic motor drive monitors requiring stable component supply and long-term manufacturability.

Supply support for MC908KX2MDWER 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) is a pioneer in 8-bit and 32-bit microcontrollers, known for automotive-grade reliability, robust toolchains, and long-lifecycle product support.

The MC908KX2MDWER belongs to the M68HC08 family designed for cost-optimized, low-pin-count embedded control - emphasizing integrated peripherals (KBI, ADC, LVI), flash endurance, and operation across extended industrial temperature ranges.

FAQ

What is the maximum operating frequency of the MC908KX2MDWER?

The MC908KX2MDWER supports a maximum internal bus frequency of 8 MHz, achievable via its Internal Clock Generator using either the internal DCO or an external crystal up to 8 MHz. This frequency governs instruction execution speed and peripheral timing - for example, ADC conversions complete in 4–20 µs depending on bus speed and prescaler settings. The device maintains specification compliance across its full –40°C to +125°C operating range at this rate.

Does the MC908KX2MDWER include an integrated debugger interface?

No, the MC908KX2MDWER does not include an on-chip debug interface such as BDM or SWD. Programming and debugging require use of the on-chip monitor ROM via the IRQ1 pin in forced monitor mode, as documented in Section 16 of the MC68HC908KX8/KX2 data sheet. This method supports flash programming and basic run-control but lacks real-time trace or hardware breakpoints found in modern debug architectures.

Can the MC908KX2MDWER operate without an external crystal?

Yes, the MC908KX2MDWER can operate without an external crystal by using its internal Digitally Controlled Oscillator (DCO) within the ICG module. The DCO delivers 1–8 MHz output with ±2% typical accuracy over temperature and voltage - sufficient for non-timing-critical applications like keypad scanning and LED control. External crystal is only required when tighter frequency tolerance (e.g., for UART communication) is needed.

What is the function of the VREFH pin on the MC908KX2MDWER?

The VREFH pin on the MC908KX2MDWER serves as the high-side voltage reference for the 8-bit ADC. It can be connected to VDD for ratiometric measurements or to a precision external voltage (e.g., 2.5 V) to fix the ADC's full-scale range independently of supply variation. This pin directly determines conversion accuracy - for instance, a 5.0 V VREFH yields 19.5 mV/LSB step size, while 2.5 V yields 9.8 mV/LSB - enabling flexible analog signal scaling.

Is the MC908KX2MDWER pin-compatible with other members of the KX series?

Yes, the MC908KX2MDWER is pin-compatible with the MC908KX8CDWE and MC908KX1CDWE in the 20-pin SOIC package, sharing identical pin assignments for VDD, VSS, IRQ1, PTA0–PTA4, PTB0–PTB7, OSC1/OSC2, and VREFH. Firmware written for MC908KX2MDWER will run unmodified on MC908KX8CDWE, though FLASH size differences must be accounted for during linking and programming.