NXP Semiconductors MC68SEC000AA20B1

Overview

MC68SEC000AA20B1 from Motorola is a static 32-bit embedded microprocessor designed for ultra-low-power battery-operated systems. It delivers 20 MHz operation at 3.3V or 5.0V, consumes only 0.5 µA in static standby mode, features a 24-bit address bus (16 MB addressing), and supports pin-for-pin replacement of the MC68EC000 in portable measuring equipment and handheld consumer devices.

For engineers reviewing the MC68SEC000AA20B1 datasheet, MC68SEC000AA20B1 pinout, MC68SEC000AA20B1 application, or MC68SEC000AA20B1 equivalent, key selection criteria include static low-power operation, 8/16-bit data bus configurability via MODE pin, object-code compatibility with the full M68000 Family, and support for interrupt-driven power management in resource-constrained embedded designs.

Technical Context

The MC68SEC000AA20B1 implements a fully static HCMOS version of the M68000 architecture with eight 32-bit data and address registers, 14 addressing modes, and memory-mapped I/O. Its bus controller handles asynchronous transfers using AS, R/W, UDS/LDS, and DTACK signals, enabling direct interfacing with off-chip peripherals without external glue logic.

Interrupt handling includes seven priority levels (IPL0–IPL2 + nonmaskable Level 7) with automatic vectoring via AVEC input, while processor status outputs FC2–FC0 indicate current execution mode (user/supervisor) and address space during active address strobes - critical for real-time OS context switching and privilege-aware firmware.

Key Specifications

Pinout & Package

MC68SEC000AA20B1 is supplied in a 64-lead Thin Quad Flat Pack (TQFP) with 0.5 mm lead pitch and 10.0 mm × 10.0 mm body size - optimized for handheld and battery-powered applications requiring minimal board area.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC68EC000RC20 and MC68332ACPV16, the MC68SEC000AA20B1 uniquely combines M68000 binary compatibility, sub-microamp standby, and static clock-stop - making it the only viable option for upgrading legacy 68EC000 designs to battery operation without firmware or PCB revision.

Availability

MC68SEC000AA20B1 is available at Aetrix Electronics and suitable for portable medical instruments, handheld test equipment, and battery-operated consumer electronics requiring stable component supply across extended product lifecycles.

Supply support for MC68SEC000AA20B1 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

Motorola Semiconductor (later Freescale, now NXP) pioneered high-reliability embedded processors for industrial and communications markets, emphasizing architectural longevity and toolchain stability.

The MC68SEC000AA20B1 belongs to the M68000-family static microprocessor line, engineered specifically to extend battery life in portable embedded systems while preserving full software and hardware compatibility with the established MC68EC000 ecosystem.

FAQ

What is the operating voltage range supported by the MC68SEC000AA20B1?

The MC68SEC000AA20B1 operates across two voltage domains: 3.3V ±0.3V and 5.0V ±0.5V. This dual-voltage capability allows direct integration into both legacy 5V designs and modern low-power 3.3V systems without level-shifting circuitry. The 3.3V mode enables the 0.5 µA standby current specification, while 5V operation maintains compatibility with older peripheral ICs. Voltage selection is determined by the VCC supply rail applied during power-up.

Is the MC68SEC000AA20B1 pin-compatible with the MC68EC000?

Yes, the MC68SEC000AA20B1 is pin-for-pin compatible with the MC68EC000 in both 64-pin QFP and TQFP packages. Signal assignments, pin locations, and electrical characteristics match identically - enabling direct PCB substitution without layout modification. This compatibility extends to all control, address, data, and interrupt signals shown in the official package diagram, including AS, R/W, UDS, LDS, DTACK, IPL0–IPL2, and FC0–FC2.

Does the MC68SEC000AA20B1 support 8-bit or 16-bit data bus operation?

The MC68SEC000AA20B1 supports both 8-bit and 16-bit data bus widths, selected statically via the MODE pin at power-up. When MODE = HIGH, the processor uses D15–D0 as a full 16-bit bidirectional data bus; when MODE = LOW, it operates in 8-bit mode using D7–D0, with upper data byte transfers handled sequentially. This configurability allows optimization for cost-sensitive 8-bit memory subsystems or performance-oriented 16-bit interfaces.

What is the significance of the 'AA20B1' suffix in MC68SEC000AA20B1?

The 'AA20B1' suffix in MC68SEC000AA20B1 indicates a specific configuration: 'AA' denotes the TQFP package variant, '20' specifies 20 MHz maximum clock speed, 'B' identifies the commercial temperature grade (0°C to +70°C), and '1' reflects a particular mask revision or process iteration. This ordering code maps directly to the 'PB' suffix in Motorola's official ordering table for the 64-pin TQFP, 20 MHz, 0°C to +70°C version.

How does the MC68SEC000AA20B1 achieve ultra-low standby current?

The MC68SEC000AA20B1 achieves 0.5 µA typical standby current through its fully static HCMOS design, which eliminates dynamic power consumption by allowing the clock to be stopped indefinitely while retaining register and memory contents. Power reduction is enforced by halting the internal clock generator and disabling non-essential bias circuits - a capability confirmed in the product brief and enabled via the HALT signal. No external power gating or special sequencing is required beyond asserting HALT and maintaining VCC.