NXP Semiconductors MC908KX2CPE

Overview

MC908KX2CPE from Freescale Semiconductor is an 8-bit HCS08-core microcontroller with 2 KB FLASH, 128 B RAM, integrated ADC, SCI, TIM, and KBI modules, operating at up to 8 MHz internal bus frequency in industrial temperature range (–40°C to +125°C). It targets low-cost embedded control in automotive body electronics and industrial sensor interfaces.

For engineers reviewing the MC908KX2CPE datasheet, MC908KX2CPE pinout, MC908KX2CPE application, or MC908KX2CPE equivalent, key selection criteria include its 2 KB FLASH density, 5-channel 8-bit ADC with VREFH reference support, IRQ1 external interrupt with 19–43 kΩ pullup, on-chip COP watchdog, and ICG-based clock generation with DCO trim capability.

Technical Context

The MC908KX2CPE implements the HCS08 CPU core with 16-bit address space, supporting WAIT/STOP low-power modes and a configurable Internal Clock Generator (ICG) featuring a digitally controlled oscillator (DCO), modulo-N divider, and digital loop filter for stable frequency synthesis. Its ICG supports both internal DCO and external crystal/oscillator sources.

It integrates a 5-channel 8-bit successive-approximation ADC with programmable conversion time, a single-channel Serial Communications Interface (SCI) compatible with RS-232 levels via external driver, and a Timer Interface Module (TIM) with input capture, output compare, and PWM generation functions - all mapped to shared PORTA and PORTB pins.

Key Specifications

Pinout & Package

MC908KX2CPE is housed in a 28-pin Plastic Dual In-line Package (PDIP) with 0.3-inch body width and 0.1-inch lead pitch, designed for through-hole PCB assembly and legacy industrial prototyping.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC908KX8CPE and MC9RS08KA2CPE, the MC908KX2CPE offers optimal balance of proven HCS08 software compatibility, sufficient memory for basic control tasks, and full peripheral integration - making it ideal for cost-sensitive, temperature-resilient industrial replacements where pin-for-pin upgrade path matters.

Availability

MC908KX2CPE is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor nodes, and appliance motor controllers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MC908KX2CPE 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) was a leading designer of embedded processors, analog, and connectivity solutions for automotive, industrial, and consumer markets.

The MC908KX2CPE belongs to the HCS08 family - engineered for cost-effective, robust 8-bit control in harsh environments, emphasizing peripheral integration, flash reliability, and wide-temperature operation without external support components.

FAQ

What is the maximum operating frequency of the MC908KX2CPE?

The MC908KX2CPE supports a maximum internal bus clock frequency of 20 MHz, achieved via the Internal Clock Generator (ICG) using its digitally controlled oscillator (DCO) and programmable divider. The core executes instructions at this bus rate, with typical performance of 10 million instructions per second (MIPS) at 20 MHz. External crystal or RC oscillator inputs can be used to derive this clock, and the ICG Trim Register allows fine-tuning within ±15%.

Does the MC908KX2CPE support in-circuit programming and debugging?

Yes, the MC908KX2CPE supports in-circuit programming and debugging via its built-in monitor ROM and dedicated test interface. Using the IRQ1 pin in conjunction with VTST and appropriate resistor values (e.g., 1 kΩ between VTST and IRQ1), designers can enter monitor mode to erase, program, or verify FLASH memory without removing the device from the board. This capability is documented in Section 16 of the MC68HC908KX8/KX2 data sheet.

What are the ADC reference options for the MC908KX2CPE?

The MC908KX2CPE ADC supports two reference configurations: externally applied voltage on the VREFH pin (0 V to VDD), enabling ratiometric measurements, or internal bandgap reference (~2.5 V) selected via CONFIG register bits. The ADC uses VREFH as the upper reference; VSS serves as the lower reference. No separate VREFL pin is provided - the lower bound is fixed to ground.

How does the Keyboard Interrupt Module (KBI) function on the MC908KX2CPE?

The KBI on the MC908KX2CPE monitors PTA0–PTA4 for state changes, generating an interrupt when any of these pins transitions (configurable edge polarity). It operates independently of CPU activity and supports wake-from-WAIT/STOP modes. Each pin has individual enable/disable control in the KBI interrupt enable register, and debouncing is implemented in firmware - the hardware provides only edge detection and interrupt flagging.

Is the MC908KX2CPE pin-compatible with other members of the KX family?

Yes, the MC908KX2CPE is pin-compatible with the MC908KX8CPE and MC908KX16CPE in the 28-pin PDIP package. All share identical pin assignments for VDD, VSS, OSC1/OSC2, IRQ1, PTA0–PTA4, PTB0–PTB7, and VREFH. Firmware written for the MC908KX2CPE will run unmodified on the KX8 and KX16 variants, though memory-mapped registers beyond 2 KB FLASH are inaccessible on the MC908KX2CPE.