NXP Semiconductors MC68SEC000AA20R2

Overview

MC68SEC000AA20R2 from Motorola (later Freescale) is a static 32-bit embedded microprocessor designed for ultra-low-power portable systems. It delivers 20 MHz operation at 3.3 V or 5.0 V, features a 24-bit address bus (16 MB addressing), 16-bit data bus (8/16-bit mode selectable), and consumes only 0.5 µA in static standby - enabling use in battery-operated handheld consumer devices.

For engineers reviewing the MC68SEC000AA20R2 datasheet, MC68SEC000AA20R2 pinout, MC68SEC000AA20R2 application, or MC68SEC000AA20R2 equivalent, key selection criteria include static low-power capability, M68000 family object-code compatibility, pin-for-pin equivalence with MC68EC000, and support for memory-mapped I/O in resource-constrained embedded designs.

Technical Context

The MC68SEC000AA20R2 implements a fully static HCMOS version of the M68000 architecture with eight 32-bit data registers and eight 32-bit address registers. Its asynchronous bus controller supports programmable wait states via DTACK, and its function code outputs (FC2–FC0) dynamically indicate supervisor/user mode and address space during active cycles.

Interrupt handling includes seven priority levels (IPL2–IPL0), nonmaskable Level 7, and autovectoring via AVEC input. Bus arbitration uses BR/BG signals for multi-master systems, while MODE pin selects between 8-bit and 16-bit data transfer modes - all without requiring external clock gating logic due to inherent static design.

Key Specifications

Pinout & Package

MC68SEC000AA20R2 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 space-constrained portable electronics.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC68EC000RC20 and MC68332ACPV16, the MC68SEC000AA20R2 uniquely combines M68000 binary compatibility, true static low-power operation, and TQFP packaging - making it the only option that preserves legacy software while enabling multi-week battery life in handheld form factors.

Availability

MC68SEC000AA20R2 is available at Aetrix Electronics and suitable for portable medical instruments, handheld test equipment, electronic games, and personal digital assistants requiring stable component supply across extended production lifecycles.

Supply support for MC68SEC000AA20R2 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 Semiconductor) was a pioneering developer of 32-bit embedded microprocessors and communications ICs, known for the M68000 family and wireless infrastructure solutions.

The MC68SEC000AA20R2 belongs to Motorola's static embedded processor line, engineered specifically to extend battery life in portable consumer electronics while maintaining full software and hardware compatibility with the broader M68000 ecosystem.

FAQ

What voltage levels does the MC68SEC000AA20R2 support?

The MC68SEC000AA20R2 operates at either 3.3 V or 5.0 V, allowing direct integration into both legacy 5 V designs and modern low-voltage systems. Its HCMOS process ensures stable 20 MHz operation across this dual-voltage range without external level-shifting circuitry - a key enabler for backward-compatible upgrades and mixed-voltage board designs.

Is the MC68SEC000AA20R2 pin-compatible with the MC68EC000?

Yes, the MC68SEC000AA20R2 is pin-for-pin compatible with the MC68EC000 in the 64-lead plastic QFP and TQFP packages. This compatibility extends to signal definitions, timing relationships, and power/ground pin assignments - permitting direct substitution in existing MC68EC000-based PCBs without layout modification or signal integrity revalidation.

Does the MC68SEC000AA20R2 support 8-bit peripheral interfaces?

Yes, the MC68SEC000AA20R2 supports 8-bit data transfers via its MODE pin: when MODE is held low at power-up, the processor configures D7–D0 as the active data path while ignoring D15–D8. This allows seamless connection to legacy 8-bit peripherals such as UARTs, LCD controllers, and EEPROMs without glue logic.

How does the MC68SEC000AA20R2 achieve 0.5 µA standby current?

The MC68SEC000AA20R2 achieves 0.5 µA typical standby current through its fully static HCMOS design, which eliminates dynamic power consumption by removing reliance on clock-driven latches. When the clock is stopped (e.g., via HALT assertion), all internal registers and logic retain state with only leakage current flowing - enabling true zero-power sleep in battery-critical applications.

What documentation is required to implement interrupt handling on the MC68SEC000AA20R2?

To implement interrupt handling on the MC68SEC000AA20R2, engineers must reference the M68000 Family Programmer's Reference Manual (M68000PM/AD) for vector table layout and exception processing, plus the Addendum to M68000 Users Manual (M68000UMAD/AD) for low-power mode entry/exit sequences involving IPL0–IPL2 and AVEC. These documents define exact timing, priority encoding, and autovector behavior specific to the MC68SEC000AA20R2.