NXP Semiconductors MC908QT4AMPE

Overview

MC908QT4AMPE from Freescale Semiconductor is an 8-bit HCS08-core microcontroller with 4 KB on-chip FLASH, 192 B RAM, and integrated 10-bit ADC, AWU, COP watchdog, LVI, and keyboard interrupt module. It operates at up to 8 MHz bus frequency, supports internal RC/XTAL oscillators, and targets low-cost embedded control in industrial sensors and appliance UIs.

For engineers reviewing the MC908QT4AMPE datasheet, MC908QT4AMPE pinout, MC908QT4AMPE application, or MC908QT4AMPE equivalent, this page delivers verified technical context, package mapping, security byte configuration requirements, oscillator trimming details, and validated alternative options for legacy HCS08 migration paths.

Technical Context

The MC908QT4AMPE implements the HCS08 CPU core with 16-bit address space, 8-level hardware stack, and instruction set optimized for compact code density. Its memory subsystem includes 4 KB FLASH (with block protection and EEPROM emulation), 192 B RAM, and dedicated register pages for peripheral control.

Peripherals include a 10-bit ADC with 8 input channels, Auto Wakeup Module with programmable timeout, Computer Operating Properly (COP) watchdog with selectable timeout, Low-Voltage Inhibit (LVI) with hysteresis, and Keyboard Interrupt Module supporting up to 8 keys. Security enforcement requires user-programmed $FFF6–$FFFD bytes; monitor mode entry is denied if ≥5 of those bytes are zero.

Key Specifications

Pinout & Package

MC908QT4AMPE is housed in a 20-pin SOIC (Small Outline Integrated Circuit) package with 18 I/O pins, VDD/VSS power rails, and dedicated reset/IRQ/KBI inputs. Pin functions are multiplexed across PORTA and PORTB registers per configuration register settings.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC908QT4AMPE, MC908QT2AMPE offers reduced memory at lower cost for simpler tasks, while MC908QY4AMPE provides pin-compatible expansion with more I/O and ADC resources - both share identical security architecture and HCS08 instruction compatibility.

Availability

MC908QT4AMPE is available at Aetrix Electronics and suitable for industrial sensor nodes, home appliance control panels, and legacy automotive body control modules requiring stable component supply and long-term lifecycle support.

Supply support for MC908QT4AMPE 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 MC908QT4AMPE belongs to the HCS08 QTA family - engineered for cost-sensitive, low-power 8-bit control applications where Flash-based programmability, integrated peripherals, and robust security are essential.

FAQ

What is the maximum bus frequency supported by the MC908QT4AMPE?

The MC908QT4AMPE supports a maximum bus frequency of 8 MHz. This value is derived from its internal oscillator (trimmable RC) or external crystal/clock source, and directly governs instruction cycle timing, ADC conversion rate, and peripheral response latency. The actual achievable frequency depends on supply voltage and temperature conditions specified in the electrical characteristics table.

How does the security feature in MC908QT4AMPE prevent unauthorized FLASH access?

The MC908QT4AMPE enforces security by requiring eight user-defined bytes programmed into FLASH addresses $FFF6–$FFFD. During monitor mode entry, the host must transmit matching bytes; if five or more are zero, monitor mode is denied. This prevents casual readout of protected firmware and ensures only authorized debug tools gain access to internal memory.

Can the MC908QT4AMPE operate without an external crystal?

Yes, the MC908QT4AMPE can operate using its internal RC oscillator, which is factory-trimmed and further adjustable via the TRIM register. This eliminates the need for external crystals in cost-sensitive or space-constrained designs, though timing accuracy is ±2% versus ±50 ppm for crystal-based operation.

What peripheral modules are integrated into the MC908QT4AMPE?

The MC908QT4AMPE integrates a 10-bit ADC with 8 channels, Auto Wakeup Module (AWU), Computer Operating Properly (COP) watchdog, Low-Voltage Inhibit (LVI), Keyboard Interrupt Module (KBI), and system-level timers. All are accessible via memory-mapped registers and support low-power modes including Wait and Stop.

Is the MC908QT4AMPE pin-compatible with other devices in the QTA family?

Yes, the MC908QT4AMPE shares the same 20-pin SOIC package and pinout with MC908QT2AMPE and MC908QT1AMPE. This allows direct substitution within the same footprint when memory or performance requirements change, provided firmware accommodates differences in FLASH size and peripheral enablement.