NXP Semiconductors MC68LC302AF20VCT

Overview

MC68LC302AF20VCT from Freescale is a low-cost integrated multiprotocol processor featuring a static 68000 core, two full-duplex SCCs, three timers (including watchdog and PIT), 1152-byte on-chip dual-port RAM, and 4 programmable chip-select lines - designed for embedded communications and portable control systems operating at 20 MHz with 3.3 V supply.

For engineers reviewing the MC68LC302AF20VCT datasheet, MC68LC302AF20VCT pinout, MC68LC302AF20VCT application, or MC68LC302AF20VCT equivalent, key selection considerations include its 100-pin TQFP package, absence of SCC3, glueless memory interface (WEH/WEL/OE), PLL support for 32 kHz or 4 MHz crystals, and dual wake-up pin capability in low-power standby modes.

Technical Context

The MC68LC302AF20VCT implements a static M68000 CPU core with 8/16-bit data bus support and integrates a System Integration Block (SIB) containing interrupt controller, PIO ports, IDMA, and system control logic. Its Communication Processor (CP) provides two independent SCCs supporting HDLC/SDLC, UART, BISYNC, and transparent protocols with autobaud.

It features an on-chip PLL with MODCLK input for clock generation from 32 kHz or 4 MHz crystals, dedicated low-power control with wake-up from PIT or two GPIO pins (PB8/PB9), and freeze debugging support only in PGA variants - not applicable to the TQFP-packaged MC68LC302AF20VCT.

Key Specifications

Pinout & Package

MC68LC302AF20VCT is housed in a 100-pin TQFP (Thin Quad Flat Pack) package with 0.5 mm pitch, measuring 14 mm × 14 mm × 1.4 mm - optimized for space- and height-sensitive 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 MC68EC000FN16, the MC68LC302AF20VCT delivers optimal balance of integration, low-power capability, and compact packaging - making it preferable for space-constrained, battery-aware, dual-protocol embedded systems where SCC3 is unnecessary.

Availability

MC68LC302AF20VCT is available at Aetrix Electronics and suitable for modem terminal control, PCMCIA network cards, portable data collectors, and industrial serial gateways requiring stable component supply and long-term design continuity.

Supply support for MC68LC302AF20VCT 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 to deliver cost-optimized, low-power versions of the MC68302 IMP family - targeting portable, space-constrained, and battery-operated communications equipment requiring integrated protocol handling and deterministic real-time control.

FAQ

What is the core architecture of the MC68LC302AF20VCT?

The MC68LC302AF20VCT uses a static implementation of the Motorola 68000 CPU core, fully compatible with the M68000 instruction set and supporting both 8-bit and 16-bit data bus configurations. This architecture enables zero-wait-state operation, deterministic timing, and true low-power stop modes - critical for portable and battery-powered applications where the MC68LC302AF20VCT is deployed.

Does the MC68LC302AF20VCT support a third serial communication controller (SCC3)?

No, the MC68LC302AF20VCT does not include SCC3 or its associated baud rate generator (BRG3). This omission is a deliberate design difference from the MC68302, reducing pin count to 100 and enabling the smaller TQFP package. The MC68LC302AF20VCT retains only two full-duplex SCCs (SCC1 and SCC2), which remain functionally identical to those in the MC68302.

What clock sources does the MC68LC302AF20VCT support via its on-chip PLL?

The MC68LC302AF20VCT supports two PLL reference clock sources: a 32 kHz crystal for ultra-low-power real-time clock operation and a 4 MHz crystal for higher-frequency system clock generation. The MODCLK pin is sampled after reset to determine which source is used - directly impacting power budget and wake-up timing behavior in applications using the MC68LC302AF20VCT.

Can the MC68LC302AF20VCT operate in slave (CPU disabled) mode?

Yes, the MC68LC302AF20VCT supports slave mode via the DISCPU pin, allowing it to function as an intelligent peripheral under host CPU control. In this mode, it retains full access to its two SCCs, timers, chip selects, and dual-port RAM while releasing the address/data bus - enabling efficient DMA-driven co-processing in systems where the MC68LC302AF20VCT serves as a protocol offload engine.

What is the significance of the 'V' suffix in MC68LC302AF20VCT?

The 'V' suffix in MC68LC302AF20VCT indicates a 3.3 V supply voltage rating, distinguishing it from 5 V variants like MC68LC302RC20. This version operates at 3.3 V ±0.3 V, enabling lower dynamic power consumption and compatibility with modern low-voltage system designs - a key specification for portable and energy-sensitive applications where the MC68LC302AF20VCT is specified.