NXP Semiconductors MC68HC908JB8JPE

Overview

MC68HC908JB8JPE from Freescale Semiconductor is an 8-bit HCS08 microcontroller with 8 KB on-chip FLASH, 512 B RAM, integrated USB 1.1 low-speed interface, and 40-pin QFP package. It operates at up to 8 MHz bus frequency, supports in-circuit programming via MON ROM, and includes TIM, KBI, COP, and LVI modules for embedded control applications including USB peripherals and industrial sensors.

For engineers reviewing the MC68HC908JB8JPE datasheet, MC68HC908JB8JPE pinout, MC68HC908JB8JPE application, or MC68HC908JB8JPE equivalent, key selection criteria include USB transceiver integration, FLASH endurance (10k erase/write cycles), 2.7–5.5 V operating range, 40-pin QFP mechanical compatibility, and MON ROM-based debug and programming capability.

Technical Context

The MC68HC908JB8JPE implements the HCS08 CPU core with enhanced addressing modes and a 16-bit index register. Its USB module complies with USB Specification Rev 1.1 for low-speed (1.5 Mbps) device operation and integrates a voltage regulator, transceiver, and endpoint buffers for endpoints 0, 1, and 2.

System-level timing is managed by the SIM module, which controls bus clock generation, reset sequencing (POR, LVI, COP, USB), and low-power modes (Wait/Stop). The TIM module provides input capture, output compare, and PWM with dedicated I/O pins PTE0/TCLK, PTE1/TCH0, and PTE2/TCH1.

Key Specifications

Pinout & Package

MC68HC908JB8JPE is housed in a 40-pin QFP (case 824A) with 0.8 mm lead pitch and exposed thermal pad. Pin assignments follow standard HCS08 I/O port mapping across Ports A–E, with dedicated USB D+/D–, oscillator, reset, and power pins.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC9RS08KA8 and MC9S08JS16, the MC68HC908JB8JPE offers unique integration of USB transceiver and MON ROM in a 40-pin QFP, enabling compact, self-programmable USB peripherals without external components or layout changes.

Availability

MC68HC908JB8JPE is available at Aetrix Electronics and suitable for USB peripheral development, industrial sensor nodes, embedded control panels, and legacy-to-USB bridge applications requiring stable component supply and long-term manufacturability.

Supply support for MC68HC908JB8JPE 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 fabless semiconductor company specializing in microcontrollers, analog, and connectivity solutions for automotive, industrial, and consumer markets.

The MC68HC908JB8JPE belongs to the HCS08 microcontroller family, designed specifically for cost-sensitive, USB-enabled embedded applications requiring robust on-chip peripherals and in-field programmability.

FAQ

What is the maximum operating frequency of the MC68HC908JB8JPE?

The MC68HC908JB8JPE supports a maximum bus frequency of 8 MHz, derived from its internal clock generator and oscillator circuitry. This frequency defines the timing boundary for all on-chip peripherals including TIM, USB, and I/O ports. Operation above this limit is not guaranteed and may result in undefined behavior or failure to meet AC timing specifications per Section 18.6 of the datasheet.

Does the MC68HC908JB8JPE support in-system programming without external hardware?

Yes, the MC68HC908JB8JPE includes a 1 KB Monitor ROM (MON) that enables in-system programming via UART using standard terminal commands. No external programmer is required - firmware updates and memory verification can be performed directly through the PTA/PTB UART interface or via USB CDC ACM using the MON's built-in command set, as documented in Section 10.

Is the USB interface on the MC68HC908JB8JPE compatible with USB 2.0 hosts?

Yes, the MC68HC908JB8JPE implements USB Specification Rev 1.1 for low-speed (1.5 Mbps) device operation, which is fully backward compatible with all USB 2.0 and USB 3.x hosts. It enumerates as a standard low-speed device and requires no driver modification on Windows, macOS, or Linux systems supporting HID or CDC classes.

What power supply voltage range does the MC68HC908JB8JPE support?

The MC68HC908JB8JPE operates across a supply voltage range of 2.7 V to 5.5 V, as specified in Section 18.6 of the datasheet. This wide range allows direct interfacing with both 3.3 V and 5 V logic systems and accommodates battery-powered applications with gradual voltage decay, supported by the integrated Low-Voltage Inhibit (LVI) circuit.

Can the MC68HC908JB8JPE enter low-power Stop mode while maintaining USB connectivity?

No - USB communication cannot be sustained in Stop mode because the USB module clock is disabled and the internal voltage regulator is powered down. The MC68HC908JB8JPE supports USB resume from Wait mode only; Stop mode requires full USB re-enumeration upon wake. For USB suspend/resume use cases, designers must remain in Wait mode with USB clocks active, as detailed in Section 9.5.3 and 9.5.4.