NXP Semiconductors MC68LC302PU20VCT

Overview

MC68LC302PU20VCT from Freescale is a low-cost integrated multiprotocol processor featuring a static 68000 core, dual serial communication controllers (SCCs), three timers including watchdog and periodic interrupt timer (PIT), 1152-byte on-chip dual-port RAM, and 4 programmable chip-select lines. It operates at 20 MHz, supports 3.3 V supply, and targets space- and power-constrained embedded systems such as PCMCIA cards and portable industrial controllers.

For engineers reviewing the MC68LC302PU20VCT datasheet, MC68LC302PU20VCT pinout, MC68LC302PU20VCT application, or MC68LC302PU20VCT equivalent, key selection considerations include its 100-pin TQFP package, absence of SCC3, reduced bus arbitration capability versus MC68302, PLL support for 32 kHz/4 MHz crystals, and slave-mode operation with DMA-driven peripheral functionality.

Technical Context

The MC68LC302PU20VCT implements a static M68000 CPU core with full 16-bit instruction compatibility and optional 8-bit boot mode. Its System Integration Block (SIB) integrates an interrupt controller with two operational modes, parallel I/O ports with interrupt capability, and glueless memory interface logic using WEH/WEL/OE signals instead of UDS/LDS/RW.

It features an on-chip PLL supporting 32 kHz or 4 MHz crystal inputs, enabling low-power clock generation and system-wide clock distribution. The device retains CPU disable (slave) mode with BR/BG/BGACK available in that configuration, but removes external bus arbitration pins (BG, BGACK, BR) in normal master mode - limiting external bus mastership outside slave mode.

Key Specifications

Pinout & Package

MC68LC302PU20VCT 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. This package eliminates height constraints in slim-profile applications like PCMCIA cards and supports surface-mount assembly.

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 MC68LC302PU20VCT trades serial channel count and bus flexibility for compact size, 3.3 V operation, and integrated low-power PLL - making it optimal for cost-sensitive, space-constrained, and battery-aware embedded controllers where exactly two serial links suffice.

Availability

MC68LC302PU20VCT is available at Aetrix Electronics and suitable for PCMCIA card design, portable medical instrumentation, industrial data loggers, and modem-on-board communication modules requiring stable component supply and long-term lifecycle support.

Supply support for MC68LC302PU20VCT 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 devices for automotive, industrial, and networking markets.

The MC68LC302PU20VCT belongs to Freescale's Integrated Multiprotocol Processor (IMP) family, engineered to deliver cost-optimized, low-power communication control in compact embedded systems with dual-serial-channel requirements.

FAQ

What is the operating voltage range for MC68LC302PU20VCT?

The MC68LC302PU20VCT operates at a nominal supply voltage of 3.3 V with a tolerance of ±0.3 V (3.0 V to 3.6 V). This 3.3 V specification enables compatibility with modern low-voltage logic families and contributes to reduced dynamic power consumption compared to 5 V variants like the MC68302. The MC68LC302PU20VCT must not be operated outside this range to ensure reliable timing and avoid damage.

Does MC68LC302PU20VCT support external bus mastership in normal operation?

No, the MC68LC302PU20VCT does not support full external bus mastership in normal master mode because bus arbitration pins (BG, BGACK, BR) were removed to reduce pin count from 132 to 100. However, external bus control remains possible in CPU disable (slave) mode, where those signals are remapped to IPL2–IPL0 pins. So while MC68LC302PU20VCT can function as a peripheral under external control, it cannot yield the bus to another master during active CPU operation.

How many serial communication controllers does MC68LC302PU20VCT include?

The MC68LC302PU20VCT includes two independent full-duplex Serial Communication Controllers (SCCs), supporting protocols including HDLC/SDLC, UART, BISYNC, and transparent modes with autobaud capability. Unlike the MC68302, the MC68LC302PU20VCT omits SCC3 and its associated baud rate generator (BRG3), which is explicitly documented as a key functional reduction to achieve the smaller TQFP package and lower cost.

What clock sources does the on-chip PLL in MC68LC302PU20VCT support?

The on-chip PLL in MC68LC302PU20VCT supports two crystal frequencies: 32 kHz for ultra-low-power standby timing and 4 MHz for full-speed operation. The MODCLK pin is sampled after reset to select the crystal source, and the XFC pin connects to an external capacitor to stabilize the PLL loop. This dual-crystal capability eliminates the need for separate real-time clock and system clock crystals, simplifying board design for MC68LC302PU20VCT-based systems.

Is MC68LC302PU20VCT pin-compatible with any other Freescale IMP devices?

No, the MC68LC302PU20VCT is not pin-compatible with other Freescale IMP devices. Its 100-pin TQFP footprint differs from the 132-pin PGA of the MC68302 and the 240-pin QFP of the MC68360. Pin functions are also reorganized - for example, WEH/WEL/OE replace UDS/LDS/RW, and SCP signals are multiplexed onto PA8–PA10. Therefore, MC68LC302PU20VCT requires a dedicated PCB layout and cannot serve as a drop-in replacement for other IMP family members.