NXP Semiconductors MC68EN302PV20BT

Overview

MC68EN302PV20BT from Freescale is an integrated multiprotocol processor combining a 68000-compatible CPU core, three serial communication controllers (SCCs), a dedicated IEEE 802.3-compliant Ethernet controller with 10 Mbps half-duplex / 20 Mbps full-duplex operation, DRAM and module bus controllers, and JTAG debug support - all in a single 144-pin TQFP package rated for 20 MHz operation at 5 V and 0°C to 70°C. It targets embedded bridge/router and industrial control applications requiring glueless DRAM interfacing and deterministic serial + Ethernet I/O.

For engineers reviewing the MC68EN302PV20BT datasheet, MC68EN302PV20BT pinout, MC68EN302PV20BT application, or MC68EN302PV20BT equivalent, key selection considerations include its dual 128-byte Ethernet FIFOs, on-chip descriptor RAM, IEEE 1149.1 compliance, 256 KB maximum DRAM bank size per bank, and native 68302-style programming model compatibility - critical for legacy 68k-based system upgrades.

Technical Context

The MC68EN302PV20BT extends the MC68302 architecture with a fully integrated Ethernet controller that operates as a peer peripheral on the 68000 bus, using two dedicated DMA channels and a 1152-byte dual-port RAM for buffer descriptors. Its Ethernet protocol core handles MAC-layer functions including automatic retransmission, collision detection, frame flushing, and 64-entry CAM-based address recognition.

The DRAM controller supports two independent banks with separate RAS/CAS lines, programmable wait states (0 at 20 MHz with 100 ns DRAM), CAS-before-RAS refresh, and address multiplexing - enabling direct interface to standard DRAM without external logic. The module bus controller manages arbitration between internal and external bus masters and routes interrupts from Ethernet and DRAM subsystems.

Key Specifications

Pinout & Package

MC68EN302PV20BT is housed in a 144-lead thin quad flat pack (TQFP) with 0.5 mm lead pitch, designed for surface-mount assembly and thermal performance up to 70°C ambient. Pin assignments follow Freescale's standardized 68k-family layout with dedicated Ethernet (RX/TX/RENA/CLSN/TENA/TCLK), DRAM (RAS0/RAS1/CAS0/CAS1/DRAMRW), and module bus (BR/BG/BGACK) signal groups.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC68EN302PV20BT, the PV25BT offers higher clock headroom within identical packaging and software compatibility, while the MC68360VR66B delivers superior raw throughput and modern OS support at the cost of architectural discontinuity and toolchain migration effort.

Availability

MC68EN302PV20BT is available at Aetrix Electronics and suitable for low-end bridges, industrial protocol gateways, and remote LAN access points requiring stable component supply and long-term obsolescence management.

Supply support for MC68EN302PV20BT 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 before its 2015 acquisition.

The MC68EN302PV20BT belongs to Freescale's 68k-based Integrated Multiprotocol Processor family, engineered to extend legacy 68302 systems with integrated Ethernet and DRAM control - targeting cost-sensitive, real-time communication equipment where software compatibility and minimal external components were critical.

FAQ

What is the maximum operating frequency of the MC68EN302PV20BT?

The MC68EN302PV20BT is rated for a maximum operating frequency of 20 MHz at 5 V and 0°C to 70°C ambient temperature. This rating is specified in Freescale's official ordering information table and corresponds to guaranteed zero-wait-state DRAM access using 100 ns DRAM parts. Operation above 20 MHz is not supported for this variant - the "20" in the part number explicitly denotes the speed grade.

Does the MC68EN302PV20BT include an integrated Ethernet PHY?

No, the MC68EN302PV20BT does not include an integrated Ethernet PHY. It provides a 16-bit parallel interface to external Ethernet transceivers such as the MC68160, with dedicated pins (RX/TX/RENA/TENA/CLSN/TCLK/RCLK) for connecting to twisted-pair or AUI media. The device implements only the MAC layer per IEEE 802.3, requiring an external PHY for physical layer signaling and cable driving.

How many DRAM banks does the MC68EN302PV20BT support, and what is the maximum size per bank?

The MC68EN302PV20BT supports two independent DRAM banks via separate RAS0/RAS1 and CAS0/CAS1 signals. Each bank is programmable from 128 KB to 8 MB in size, allowing flexible memory configuration for different application requirements. The DRAM controller also supports address multiplexing and hidden refresh, enabling efficient use of standard DRAM parts without external support logic.

Is the MC68EN302PV20BT pin-compatible with the standard MC68302?

No, the MC68EN302PV20BT is not pin-compatible with the base MC68302 due to added Ethernet, DRAM, and module bus interface signals. While it retains the core 68302 programming model and shares some peripheral register layouts, the 144-pin TQFP package introduces 30+ additional pins for Ethernet control, DRAM timing, and bus arbitration - requiring a new PCB layout. Migration from MC68302 requires hardware redesign, though firmware reuse is possible for non-Ethernet functions.

What debug interfaces are available on the MC68EN302PV20BT?

The MC68EN302PV20BT includes a fully compliant IEEE 1149.1 JTAG interface with TMS, TCK, TDI, TDO, and TRST pins, supporting boundary-scan testing and in-circuit debugging. It does not include SWD, JTAG-DP, or proprietary debug ports. Debug capability relies on external JTAG emulators compatible with 68k-family tools, and the interface is functional across the full temperature range without requiring special configuration.