NXP Semiconductors MC68LC302AF25CT

Overview

MC68LC302AF25CT from Freescale is a low-cost integrated multiprotocol processor based on a static 68000 core, operating at 25 MHz with 5 V supply, featuring two full-duplex SCCs, three timers (including watchdog and PIT), 1152-byte dual-port RAM, and four chip-select lines. It targets embedded communication controllers where three serial channels are unnecessary.

For engineers reviewing the MC68LC302AF25CT datasheet, MC68LC302AF25CT pinout, MC68LC302AF25CT application, or MC68LC302AF25CT equivalent, key selection considerations include its 100-pin TQFP package, absence of SCC3, reduced bus arbitration capability, PLL support for 32 kHz/4 MHz crystals, and low-power standby modes with wake-up via PIT or two dedicated pins.

Technical Context

The MC68LC302AF25CT integrates a static M68000 CPU core with on-chip system integration block (SIB) and communications processor (CP). Its SIB includes interrupt controller, parallel I/O ports with interrupt capability, 1152-byte dual-port RAM, three timers (PIT, watchdog, general-purpose), and four programmable chip-select lines with wait-state logic.

The CP contains a RISC main controller and two independent full-duplex SCCs supporting HDLC/SDLC, UART, BISYNC, transparent modes, and autobaud. Unlike the MC68302, it omits SCC3, external bus arbitration signals (BR/BG/BGACK except in slave mode), and UDS/LDS/R/W - replaced by WEH, WEL, and OE for glueless memory interfacing.

Key Specifications

Pinout & Package

MC68LC302AF25CT is housed in a 100-pin Thin Quad Flat Pack (TQFP) package with 0.5 mm pitch, optimized for space- and height-constrained applications such as PCMCIA cards and portable terminals.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC68302RC20 and MC68360VR33B, the MC68LC302AF25CT delivers targeted functionality at lower cost and size - ideal for dual-channel protocol bridging where SCC3 and Ethernet are unnecessary, and where 25 MHz deterministic throughput suffices.

Availability

MC68LC302AF25CT is available at Aetrix Electronics and suitable for industrial RTUs, PCMCIA communication cards, point-of-sale terminals, and legacy protocol gateways requiring stable component supply across extended product lifecycles.

Supply support for MC68LC302AF25CT 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) was a leading designer of embedded processors, microcontrollers, and analog chips for automotive, industrial, and networking applications.

The MC68LC302 product line extends the MC68302 IMP family with static-core optimization, low-power enhancements, and TQFP packaging - designed specifically for cost-sensitive, space-constrained communication controllers.

FAQ

What is the core architecture of the MC68LC302AF25CT?

The MC68LC302AF25CT features a static 68000 CPU core, enabling zero-wait-state operation and full compatibility with the M68000 instruction set. This architecture supports both 8-bit and 16-bit data bus configurations and allows true low-power stop modes - a key distinction from dynamic-core predecessors. The static design eliminates external clock driver requirements and improves reliability in temperature-varying environments. The MC68LC302AF25CT maintains binary compatibility with software written for the MC68302, easing migration for existing designs.

Does the MC68LC302AF25CT support external bus mastering?

No, the MC68LC302AF25CT does not support full external bus mastering like the MC68302. Pins required for bus arbitration (BR, BG, BGACK) are omitted in the 100-pin TQFP package. However, an external master can assert HALT to suspend CPU operation and gain temporary control - but only in DISCPU (slave mode), where BR/BG/BGACK become available. This makes the MC68LC302AF25CT suitable as an intelligent peripheral, not a system bus arbiter. Designers must verify HALT-based coordination in their timing budget.

What clock sources does the MC68LC302AF25CT support?

The MC68LC302AF25CT supports two crystal-based clock inputs: a 32 kHz watch crystal for ultra-low-power standby operation and a 4 MHz crystal for active-mode PLL multiplication. The XFC pin configures PLL behavior post-reset, allowing flexible clock tree design. The on-chip PLL generates the 25 MHz system clock from either source. CLKO provides a buffered output for driving other system components. This dual-crystal capability enables precise low-power scheduling while maintaining high-speed protocol processing when active.

How many serial communication controllers does the MC68LC302AF25CT include?

The MC68LC302AF25CT includes two independent full-duplex serial communication controllers (SCCs), designated SCC1 and SCC2. Each supports HDLC/SDLC, UART, BISYNC, and transparent modes with autobaud detection. SCC3 - present in the MC68302 - is explicitly removed to reduce pin count and cost. Signal pins for SCC3 (TXD3, RXD3, RCLK3) and its baud rate generator (BRG3) are absent. Applications requiring three concurrent serial links must use the MC68302 or alternative solutions.

What package type and pin count does the MC68LC302AF25CT use?

The MC68LC302AF25CT uses a 100-pin Thin Quad Flat Pack (TQFP) package with 0.5 mm lead pitch. This package reduces board area and height versus the 132-pin PGA variant of the MC68302, making it suitable for PCMCIA cards and handheld devices. Pin assignments follow Freescale's standardized MC68LC302 layout, with muxed functions (e.g., PA8–PA10 for SCP, PA12 for MODCLK) and dedicated memory interface signals (WEH, WEL, OE). Thermal and mechanical data conform to JEDEC MO-140 standards.