NXP Semiconductors MC908JK8CDWE

Overview

MC908JK8CDWE from Freescale Semiconductor is an 8-bit HCS08 microcontroller featuring 8 KB on-chip Flash memory, 512 B RAM, and a 20 MHz CPU bus clock. It integrates a 10-bit ADC with 8 input channels, SCI serial interface, TIM module with PWM and capture/compare, and low-power stop/wait modes. Designed for cost-sensitive embedded control in appliance motor drives and industrial sensor nodes.

For engineers reviewing the MC908JK8CDWE datasheet, MC908JK8CDWE pinout, MC908JK8CDWE application, or MC908JK8CDWE equivalent, this page delivers verified electrical specs, package mapping to SOIC-28, functional pin roles, real-world use cases in motor control and sensor interfacing, and two validated alternative parts with documented differences in memory size and ADC resolution.

Technical Context

The MC908JK8CDWE implements the HCS08 CPU core with enhanced BDM debug support and executes instructions at up to 20 MHz bus clock frequency. Its System Integration Module (SIM) provides configurable clock generation from internal RC or external crystal oscillator, with programmable prescalers for peripheral timing.

It supports interrupt-driven operation via IRQ, KBI, and SCI modules, and includes a Computer Operating Properly (COP) watchdog timer with selectable timeout periods. The device uses SuperFlash® technology for reliable in-system programmability with 100K erase/write cycles and data retention exceeding 15 years.

Key Specifications

Pinout & Package

MC908JK8CDWE 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 are defined per Freescale Document MC68HC908JL8/JK8 Rev. 3.1, Section 1.4.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC908JK3CDWE, the MC908JK8CDWE adds essential ADC functionality for closed-loop control; versus MC908JK12CDWE, it trades memory margin for lower unit cost in volume production where firmware remains stable and compact.

Availability

MC908JK8CDWE is available at Aetrix Electronics and suitable for motor control, sensor node, industrial HMI, and power supply monitoring applications requiring stable component supply and long-term manufacturability.

Supply support for MC908JK8CDWE 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 microcontroller architecture, delivering robust, low-power embedded solutions for industrial and automotive markets.

The MC908JK8CDWE belongs to the HCS08 family, designed specifically for cost-optimized, real-time control in appliances, building automation, and power electronics where deterministic timing and Flash endurance are critical.

FAQ

What is the maximum operating frequency of the MC908JK8CDWE?

The MC908JK8CDWE supports a maximum bus clock frequency of 20 MHz, derived from its internal oscillator or external crystal. This corresponds to an instruction execution rate of approximately 10 million instructions per second (MIPS), enabling sub-100 µs response times for time-critical control tasks. The actual achievable frequency depends on supply voltage and temperature per Electrical Specifications Table 17-1 in the MC68HC908JL8/JK8 Rev. 3.1 datasheet.

Does the MC908JK8CDWE support in-system programming?

Yes, the MC908JK8CDWE supports in-system programming via its Background Debug Mode (BDM) interface using the BKGD pin. It requires a compatible BDM pod (e.g., P&E Micro USB-ML-CF) and Freescale's Codewarrior development environment. Flash programming is performed at standard VDD voltage with no high-voltage requirement, and the MC908JK8CDWE datasheet confirms full compatibility with standard Flash erase and write algorithms.

What are the low-power modes supported by the MC908JK8CDWE?

The MC908JK8CDWE supports Wait and Stop modes. In Wait mode, the CPU halts but peripherals remain active; wake-up occurs via IRQ, KBI, or SCI events. In Stop mode, all clocks halt except the LVI and COP circuits, reducing current to 1 µA typical. Both modes are entered via STOP or WAIT instructions and are fully documented in Chapter 5 (SIM) and Chapter 14 (COP) of the MC68HC908JL8/JK8 Rev. 3.1 datasheet.

Can the MC908JK8CDWE drive LEDs directly from its GPIO pins?

Yes, the MC908JK8CDWE GPIO pins (e.g., PTA0–PTA7, PTD0–PTD7) can source or sink up to 10 mA per pin and 50 mA total for all ports, making them suitable for direct LED driving with appropriate current-limiting resistors. Port pins support TTL-compatible output levels and include weak pull-ups for open-drain configurations. Drive capability is specified in Section 17.3 "DC Electrical Characteristics" of the MC68HC908JL8/JK8 Rev. 3.1 datasheet.

Is there hardware support for UART communication on the MC908JK8CDWE?

Yes, the MC908JK8CDWE includes a dedicated Serial Communications Interface (SCI) module supporting full-duplex UART operation. It features programmable baud rate generation, framing error detection, break detection, and interrupt-driven transmit/receive. Pins PTE0 (RxD) and PTE1 (TxD) are assigned to SCI functionality and operate across the full 2.7–5.5 V supply range, as confirmed in Section 9.7 of the MC68HC908JL8/JK8 Rev. 3.1 datasheet.