NXP Semiconductors KMC68LC302AF20CT

Overview

KMC68LC302AF20CT from Freescale is a low-cost integrated multiprotocol processor featuring a static 68000 core, two full-duplex serial communication controllers (SCCs), three timers including a watchdog and periodic interrupt timer (PIT), 1152-byte on-chip dual-port RAM, and support for 32 kHz or 4 MHz crystal-based PLL clock generation. It operates at 20 MHz, uses a 5 V supply, and targets space- and power-constrained embedded systems such as PCMCIA cards and portable industrial controllers.

For engineers reviewing the KMC68LC302AF20CT datasheet, KMC68LC302AF20CT pinout, KMC68LC302AF20CT application, or KMC68LC302AF20CT 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 dual wake-up pin support in low-power standby modes.

Technical Context

The KMC68LC302AF20CT implements a static M68000 CPU core with 8/16-bit data bus support and executes instructions compatible with the M68000 family. Its System Integration Block (SIB) integrates an interrupt controller with two operation modes, four chip-select lines with wait-state logic, and programmable address mapping for dual-port RAM and IMP registers.

Its Communications Processor (CP) contains a RISC main controller and two independent SCCs supporting HDLC/SDLC, UART, BISYNC, and transparent protocols with autobaud. The device omits SCC3 and external bus arbitration pins (BR/BG/BGACK), limiting master-mode flexibility but retaining slave-mode operation via DISCPU with BR/ BG/BGACK repurposed as IPL2–0.

Key Specifications

Pinout & Package

Package: 100-pin TQFP (Thin Quad Flat Pack), 14 mm × 14 mm, 0.5 mm pitch, lead-free RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC68302RC20 and MC68EC000FN16, the KMC68LC302AF20CT delivers optimized integration for dual-serial-channel, low-power, space-constrained applications - trading SCC3 and bus arbitration for smaller size, lower power, and simplified board design.

Availability

KMC68LC302AF20CT is available at Aetrix Electronics and suitable for PCMCIA card controllers, industrial serial gateways, portable data terminals, and intelligent peripheral controllers requiring stable component supply across extended production lifecycles.

Supply support for KMC68LC302AF20CT 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 and analog/mixed-signal ICs, focused on automotive, industrial, and networking applications.

The MC68LC302 product line was developed as a cost-optimized, space-efficient variant of the MC68302 IMP, targeting portable, low-power, and height-constrained embedded systems requiring dual-serial-channel connectivity and integrated peripherals.

FAQ

What is the core architecture of the KMC68LC302AF20CT?

The KMC68LC302AF20CT features a static 68000 CPU core fully compatible with the M68000 instruction set and supporting both 8-bit and 16-bit data bus configurations. Unlike dynamic cores, its static design enables true zero-power stop modes and eliminates refresh overhead, making it suitable for battery-operated applications where deterministic timing and ultra-low standby current are essential. This core forms the foundation of the KMC68LC302AF20CT's real-time processing capability.

Does the KMC68LC302AF20CT support external bus mastership?

No, the KMC68LC302AF20CT does not support full external bus mastership due to the removal of BR, BG, and BGACK pins required for standard arbitration. However, it retains DISCPU functionality, allowing it to operate in slave mode where an external master can control the bus using a simplified HALT-based scheme. In this mode, BR/BG/BGACK signals become available as IPL2–0, enabling KMC68LC302AF20CT to serve as an intelligent peripheral - a key distinction from master-only operation.

What clock sources does the KMC68LC302AF20CT support?

The KMC68LC302AF20CT supports two on-chip PLL configurations: 32 kHz crystal (for ultra-low-power timekeeping) and 4 MHz crystal (for higher-performance operation), selected via the MODCLK pin sampled at reset. It also accepts external clock input via EXTAL and provides a buffered CLKOUT signal. These options eliminate the need for external clock generators and allow flexible trade-offs between power consumption and processing speed in the KMC68LC302AF20CT-based design.

How many serial communication controllers does the KMC68LC302AF20CT include?

The KMC68LC302AF20CT includes two independent full-duplex serial communication controllers (SCCs), designated SCC1 and SCC2. Each supports multiple protocols including HDLC/SDLC, UART, BISYNC, and transparent modes with autobaud detection. SCC3 - present in the MC68302 - is omitted in the KMC68LC302AF20CT to reduce pin count and cost. This makes the KMC68LC302AF20CT ideal for dual-serial-channel applications but unsuitable where three concurrent serial links are required.

What is the function of the dual-port RAM in the KMC68LC302AF20CT?

The KMC68LC302AF20CT integrates 1152 bytes of on-chip dual-port RAM, allowing simultaneous, conflict-free access by the CPU and internal peripherals such as the SCCs and timers via DMA. This eliminates bus contention and external memory latency, enabling efficient buffering of serial data, protocol state storage, and real-time interrupt handling. The RAM is programmably mapped within the KMC68LC302AF20CT's address space and serves as a critical resource for deterministic, low-overhead communications processing.