NXP Semiconductors MC908JK8MDWE

Overview

MC908JK8MDWE from Freescale Semiconductor is an 8-bit HCS08-core microcontroller with 8 KB on-chip Flash, 512 B RAM, and integrated peripherals including SCI, TIM, ADC (8-channel, 10-bit), KBI, and COP watchdog. It operates at up to 8 MHz bus frequency, supports 2.7–5.5 V supply, and targets low-cost embedded control in industrial sensors and appliance subsystems.

For engineers reviewing the MC908JK8MDWE datasheet, MC908JK8MDWE pinout, MC908JK8MDWE application, or MC908JK8MDWE equivalent, key selection criteria include its 20-pin SOIC-W package, internal RC oscillator accuracy (±2% over temperature), Flash endurance (10k erase/write cycles), and support for in-system programming via MON ROM bootloader.

Technical Context

The MC908JK8MDWE implements the HCS08 CPU core with enhanced addressing modes and a 16-level hardware stack. Its System Integration Module (SIM) provides bus clock generation from either external crystal (1–8 MHz) or internal RC oscillator, with configurable prescalers enabling flexible timing for peripheral modules.

Peripheral integration includes a 10-bit ADC with 8 input channels and software-selectable conversion speed (16–44 µs), a dual-channel Timer Interface Module supporting input capture, output compare, and PWM, and a full-duplex SCI module compliant with RS-232 electrical interface when paired with external level-shifting circuitry.

Key Specifications

Pinout & Package

MC908JK8MDWE is housed in a 20-pin SOIC-W (Wide) package (7.5 mm body width), RoHS-compliant, with 0.635 mm lead pitch and exposed pad not electrically connected.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC908JK8MDWE, MC908JK3E reduces memory and removes ADC to lower cost for pure digital control, while MC908JK12CDWE extends Flash capacity and operating temperature range for more demanding firmware and harsher environments - both retain identical peripheral functionality and pin compatibility.

Availability

MC908JK8MDWE is available at Aetrix Electronics and suitable for industrial sensor nodes, home appliance control units, and smart meter subsystems requiring stable component supply and long-term manufacturing continuity.

Supply support for MC908JK8MDWE 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 8-bit MCU architectures for cost-sensitive, high-volume embedded applications with robust industrial qualification.

The MC908JK8MDWE belongs to the HCS08 family, designed specifically for resource-constrained industrial and consumer control applications where Flash programmability, low-power operation, and integrated analog interfaces are essential.

FAQ

What is the maximum bus frequency supported by the MC908JK8MDWE?

The MC908JK8MDWE supports a maximum bus frequency of 8 MHz. This is achieved using the internal RC oscillator trimmed to ±2% accuracy or an external crystal oscillator up to 8 MHz. The bus clock is derived directly from the selected oscillator source with optional division via SIM registers, and all on-chip peripherals-including TIM, ADC, and SCI-are synchronized to this bus clock. MC908JK8MDWE performance remains stable across its full 2.7–5.5 V supply and –40 °C to +85 °C operating range.

Does the MC908JK8MDWE include a hardware ADC, and what are its key specifications?

Yes, the MC908JK8MDWE integrates a 10-bit successive-approximation ADC with eight single-ended input channels (AD0–AD7). Conversion time is programmable between 16 µs and 44 µs depending on resolution and clock configuration. The ADC uses the internal bandgap reference (1.25 V) or VDD as reference, supports software and hardware trigger sources, and includes dedicated result registers accessible via standard memory-mapped I/O. MC908JK8MDWE's ADC meets industrial-grade linearity and offset specifications per Freescale's Rev. 3.1 datasheet.

Can the MC908JK8MDWE operate without an external crystal?

Yes, the MC908JK8MDWE can operate entirely from its internal RC oscillator, which is factory-trimmed to ±2% accuracy across voltage and temperature. This eliminates the need for an external crystal or ceramic resonator, reducing BOM cost and PCB area. The internal oscillator supports all operating modes including Wait and Stop, and is selectable via the CONFIG1 register. MC908JK8MDWE retains full functionality-including SCI communication and ADC conversions-when using the internal RC source.

How does the Monitor ROM in the MC908JK8MDWE support firmware updates?

The MC908JK8MDWE includes 2 KB of factory-programmed Monitor ROM that implements a serial bootloader accessible via the SCI interface. This allows field firmware updates without requiring an external programmer: the host sends command sequences and binary data over UART, and the MON ROM handles Flash erasure, verification, and programming. Security features include flash protection bits and optional password lock. MC908JK8MDWE's MON ROM is active upon reset if the BKGD pin is held low, enabling reliable in-system programming throughout product life.

What low-power modes does the MC908JK8MDWE support, and what is the typical current draw in Stop mode?

The MC908JK8MDWE supports Wait and Stop low-power modes. In Stop mode, current consumption drops below 1 µA while retaining full RAM contents and enabling wake-up via IRQ, KBI, or SCI idle-line detection. The COP watchdog remains functional in Stop mode, and the internal RC oscillator stays enabled to support fast wake-up latency (< 4 µs). MC908JK8MDWE's Stop mode is fully specified across its entire operating voltage and temperature range, making it suitable for battery-powered applications requiring multi-year operation.