NXP Semiconductors MC68LC302AF20CT

Overview

MC68LC302AF20CT 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 8-/16-bit data bus operation at 20 MHz. It targets embedded control in portable, space-constrained, and low-power systems such as PCMCIA cards.

For engineers reviewing the MC68LC302AF20CT datasheet, MC68LC302AF20CT pinout, MC68LC302AF20CT application, or MC68LC302AF20CT equivalent, key selection considerations include its 100-pin TQFP package, absence of SCC3, glueless memory interface via WEH/WEL/OE, PLL support for 32 kHz or 4 MHz crystals, and dual-pin wake-up from low-power modes.

Technical Context

The MC68LC302AF20CT implements a static M68000 CPU core with full instruction set compatibility, paired with an integrated system integration block (SIB) containing interrupt controller, parallel I/O ports, four chip-select lines with wait-state logic, and programmable address mapping for dual-port RAM and IMP registers. Its communication peripheral block (CP) integrates two independent SCCs supporting HDLC/SDLC, UART, BISYNC, and transparent modes with autobaud capability.

It supports multiple power states: active, disable-CPU (slave mode), and low-power standby with wake-up via PIT, two dedicated pins (PB8/PB9), or external interrupt. The on-chip PLL accepts 32 kHz or 4 MHz input and generates internal clocks; VCCSYN/GNDSYN/XFC pins are dedicated to PLL operation, and MODCLK is sampled at reset before becoming PA12.

Key Specifications

Pinout & Package

MC68LC302AF20CT is housed in a 100-pin Thin Quad Flat Pack (TQFP) with 0.5 mm pitch, measuring 14 mm × 14 mm × 1.4 mm. This RoHS-compliant package supports reflow soldering and meets height constraints for PCMCIA and compact embedded modules.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC68302RC20 and MC68332ACPV16, the MC68LC302AF20CT delivers optimal balance of serial protocol support, low-power operation, and compact packaging for cost-sensitive portable and space-constrained embedded systems - without over-provisioning unused peripherals or requiring board redesign.

Availability

MC68LC302AF20CT is available at Aetrix Electronics and suitable for modem control units, PCMCIA network adapters, industrial serial gateways, and portable data terminals requiring stable component supply and long-term lifecycle support.

Supply support for MC68LC302AF20CT 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 for automotive, industrial, and networking markets.

The MC68LC302 product line was developed as a cost-optimized, space-efficient variant of the MC68302 IMP family - targeting portable, low-power, and height-restricted embedded applications where full bus arbitration and triple serial channels were unnecessary.

FAQ

What is the core architecture of the MC68LC302AF20CT?

The MC68LC302AF20CT features a static 68000 CPU core fully compatible with the M68000 instruction set. This architecture enables zero-wait-state execution, deterministic timing, and seamless software reuse from existing M68000-based designs. Unlike dynamic cores, it supports true static operation - allowing complete clock stoppage during low-power standby while preserving register and RAM contents. The MC68LC302AF20CT maintains full binary compatibility with earlier 68000-family code.

Does the MC68LC302AF20CT support external bus mastership like the MC68302?

No, the MC68LC302AF20CT does not support full external bus mastership as implemented in the MC68302. Pins required for bus arbitration (BR, BG, BGACK) are omitted in the 100-pin TQFP package. An external master can still assert HALT to pause the CPU, but cannot seize the bus via standard arbitration. However, in disable-CPU (slave) mode, BR, BG, and BGACK become available on IPL2–IPL0 pins, restoring limited bus-sharing capability for peripheral co-processing.

How many serial communication controllers does the MC68LC302AF20CT include?

The MC68LC302AF20CT includes two independent full-duplex serial communication controllers (SCCs): 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. This makes the MC68LC302AF20CT ideal for dual-serial applications such as modem control or serial gateway functions where a third channel is unnecessary.

What clock sources does the MC68LC302AF20CT support for its on-chip PLL?

The MC68LC302AF20CT supports two crystal-based clock inputs for its on-chip PLL: either a 32 kHz tuning-fork crystal or a 4 MHz fundamental-mode crystal. The PLL locks to either source and generates the internal system clock. Dedicated pins XFC, VCCSYN, and GNDSYN provide feedback and analog supply isolation for stable PLL operation. The MODCLK pin samples the crystal source at reset and then functions as general-purpose I/O (PA12).

Is the MC68LC302AF20CT pin-compatible with any other Freescale processors?

The MC68LC302AF20CT is not pin-compatible with the MC68302 due to its reduced 100-pin TQFP package versus the MC68302's 132-pin PGA. Pin assignments differ significantly - for example, WEH/WEL/OE replace UDS/LDS/RW, and SCP functions are muxed onto PA8–PA10. While functional overlap exists with the MC68302 in dual-SCC operation, PCB layout must be redesigned for the MC68LC302AF20CT. No other Freescale processor shares its exact 100-pin TQFP pinout.