NXP Semiconductors KMC68LC302AF25CT

Overview

KMC68LC302AF25CT from Freescale is a low-cost integrated multiprotocol processor featuring a static 68000 core, dual serial communication controllers (SCC1/SCC2), 1152-byte on-chip dual-port RAM, three timers including watchdog and periodic interrupt timer (PIT), and support for 32 kHz or 4 MHz crystal-based PLL clock generation. It operates at 25 MHz, uses 5 V supply, and targets space- and power-constrained embedded control applications such as PCMCIA cards and portable industrial terminals.

For engineers reviewing the KMC68LC302AF25CT datasheet, KMC68LC302AF25CT pinout, KMC68LC302AF25CT application, or KMC68LC302AF25CT equivalent, key selection considerations include its 100-pin TQFP package, absence of SCC3, reduced bus arbitration capability versus MC68302, glueless memory interface via WEH/WEL/OE, and low-power wake-up support via PIT or two dedicated pins.

Technical Context

The KMC68LC302AF25CT implements a static M68000 CPU core with full 16-bit/8-bit system bus compatibility, enabling boot in 8-bit mode and runtime switch to 16-bit mode. Its System Integration Block (SIB) integrates interrupt controller, parallel I/O ports with interrupt capability, four chip-select lines with wait-state logic, and programmable address mapping for dual-port RAM and IMP registers.

The Communications Processor (CP) contains two independent full-duplex SCCs supporting HDLC/SDLC, UART, BISYNC, and transparent modes with autobaud. Unlike the MC68302, it omits SCC3, BRG3, external bus arbitration signals (BG/BGACK), and UDS/LDS/R/W - replaced by WEH/WEL/OE for simplified memory interfacing.

Key Specifications

Pinout & Package

Package: 100-pin Thin Quad Flat Pack (TQFP), 14 mm × 14 mm, 0.5 mm pitch, height ≤1.2 mm - suitable for PCMCIA-compliant and height-restricted industrial modules.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar integrated multiprotocol processor applications.

Compared with MC68302RC20, KMC68LC302AF25CT trades SCC3 and bus arbitration for compact TQFP packaging and lower system cost; compared with MC68LC302PU20, it delivers 25% higher clock rate and extended temperature support, enabling deployment in harsher industrial settings.

Availability

KMC68LC302AF25CT is available at Aetrix Electronics and suitable for PCMCIA modem cards, industrial handheld terminals, smart energy meter communication modules, and legacy protocol gateways requiring stable component supply and long-term design-in support.

Supply support for KMC68LC302AF25CT 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, microcontrollers, and analog chips for automotive, industrial, and networking applications.

The MC68LC302 product line delivers cost-optimized, low-power variants of the MC68302 IMP for space-constrained, battery-aware, and legacy-protocol-intensive embedded systems.

FAQ

What is the maximum operating frequency of the KMC68LC302AF25CT?

The KMC68LC302AF25CT is rated for 25 MHz operation, confirmed by Freescale's ordering information table specifying "F25" suffix for 25 MHz grade. This frequency determines instruction cycle timing, serial baud rate limits, and real-time response capability. The device achieves this using an internal PLL locked to either a 32 kHz or 4 MHz crystal source, and requires stable 5 V ±5% supply and proper decoupling per the reference design guidelines in the MC68LC302 documentation.

Does the KMC68LC302AF25CT support three serial communication channels like the MC68302?

No, the KMC68LC302AF25CT does not support three serial communication channels. As documented in the MC68LC302 Product Brief, SCC3 and its associated baud rate generator BRG3 are explicitly removed to reduce pin count and cost. The KMC68LC302AF25CT retains only SCC1 and SCC2, each fully functional with HDLC/SDLC, UART, BISYNC, and autobaud capabilities. Applications requiring three independent serial links must use the full-featured MC68302 or alternative multi-SCC solutions.

Can the KMC68LC302AF25CT operate in low-power standby mode with wake-up capability?

Yes, the KMC68LC302AF25CT supports low-power standby modes with multiple wake-up sources. It features a dedicated Periodic Interrupt Timer (PIT) that can awaken the device at programmable intervals, plus two dedicated external pins (configurable per application) that trigger wake-up on edge transition. These capabilities are enabled by the static 68000 core and low-power control logic described in the MC68LC302 Product Information, making KMC68LC302AF25CT suitable for battery-powered telemetry and portable instrumentation.

What memory interface signals replace UDS, LDS, and R/W in the KMC68LC302AF25CT?

In the KMC68LC302AF25CT, the traditional UDS, LDS, and R/W bus control signals are omitted except in slave mode (DISCPU active). They are replaced by WEH (Write Enable High), WEL (Write Enable Low), and OE (Output Enable) - designed specifically for glueless interfacing to 8-bit and 16-bit memories. WEH/WEL selectively enable upper/lower data bytes during writes, while OE controls read data output, eliminating the need for external address latches or bus transceivers in standard memory configurations.

Is the KMC68LC302AF25CT pin-compatible with other MC68LC302 variants?

The KMC68LC302AF25CT shares identical 100-pin TQFP pinout with other PU-suffix MC68LC302 variants (e.g., MC68LC302PU16, MC68LC302PU20), as confirmed by Freescale's ordering table and pin description documentation. All PU-suffix parts use the same mechanical footprint, signal assignment, and power/ground pin locations. However, electrical ratings differ: KMC68LC302AF25CT is specified for 25 MHz operation and extended temperature range (–40°C to +85°C), whereas lower-speed variants have different AC timing and thermal specifications.