MC68302AG20C - 20MHz M68300 Integrated Comm Processor | NXP
MPN: MC68302AG20C ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $78.5 | $78.50 |
| 10 | $72.4 | $724.00 |
| 100 | $64.2 | $6,420.00 |
| 500 | $58.95 | $29,475.00 |
| 1,000 | $54.1 | $54,100.00 |
MC68302AG20C Overview
What is an integrated communications processor? An integrated communications processor (ICP) combines a general-purpose CPU core with on-chip peripherals such as DMA engines, serial channel controllers, timers, and parallel ports that are tuned for protocol handling. The M68302 was the first device to offer a closely-coupled, industry-standard MC68000/MC68008 microprocessor core combined with a flexible communications architecture, placing it inside the broader taxonomy: microcontroller -> microprocessor -> integrated communications processor -> embedded networking SoC -> semiconductor.
Key features include up to three independent serial communications controllers (SCCs) supporting HDLC/SDLC, UART, and BISYNC protocols, a 2-channel DMA engine, 1152 bytes of on-chip dual-port RAM, a 24-bit address bus providing 16 MB of linear addressing, and an interrupt controller with up to seven external interrupt sources. The device operates from a single 5 V supply and supports a maximum CPU clock of 20 MHz.
The MC68302 architecture is built around a true 32-bit internal 68000 core running with a 16-bit external data bus, allowing engineers to reuse legacy 68000 firmware while gaining dedicated serial DMA offload. The on-chip RISC communications processor (CP) handles bit-level protocol work, freeing the core for higher-layer tasks. This dual-engine design was pioneering for early 1990s networking ASICs.
Typical applications include ISDN terminal adapters, ISDN modem modules, X.25 packet switches, industrial routers, factory-floor communication controllers, and legacy telecom backplane designs. The part also appears in industrial serial-bridge gateways and protocol-conversion adapters where deterministic SCC behaviour is required.
When designing with the MC68302AG20C, ensure proper bus arbitration and timing closure for the 20 MHz external clock. The SCC pins require external transceivers for RS-232/RS-485 connectivity. According to the NXP datasheet, decoupling must be placed close to the multiple VCC/GND pairs of the LQFP-144.
This page synthesizes distributor stock signals, EOL status, drop-in 68000-family alternatives, and design notes beyond what the manufacturer datasheet alone offers.
Drop-in alternatives for MC68302AG20C — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with MC68302AG20C (same form factor and footprint) — differing in Core Architecture, Data Bus Width, Maximum Clock Frequency, RoHS Status, Mounting Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC68302AG16C
✅ Drop-In✓ In Stock
$13.55 / Unit
View Datasheet →MC68302CFC20C
✅ Drop-In📋 Reference alternative (not in catalog)
MC68302AG20C Maximum Ratings & Electrical Characteristics
| Core Architecture | M68000 / M68300 family |
| Data Bus Width | 8/16-Bit external |
| Maximum CPU Clock | 20 MHz |
| Address Bus Width | 24-Bit (16 MB linear) |
| Core Count | 1 |
| On-Chip RAM | 1152 bytes dual-port |
| Serial Communications Controllers | 3 SCCs (HDLC/SDLC, UART, BISYNC) |
| DMA Channels | 2 |
| External Interrupts | Up to 7 sources |
| Supply Voltage | 5 V |
| Package | 144-LQFP (20x20 mm) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Lead-Free | Yes |
MC68302AG20C 144-lqfp (20x20 mm) Pin Configuration Guide
Pin configuration for MC68302AG20C (144-lqfp (20x20 mm) package). This digital IC includes GPIO, communication interfaces (UART, SPI, I2C), and power pins. Refer to the manufacturer datasheet for alternate pin functions and configuration options. Essential for embedded system design and PCB layout.
No detailed pinout data available for MC68302AG20C.
Refer to the datasheet for full pin configuration.
Typical Applications
MC68302AG20C is suitable for 2 applications: ISDN Terminal Adapter, Industrial Serial Router.
ISDN Terminal Adapter
The MC68302AG20C fits ISDN terminal adapters because its three on-chip serial communications controllers natively handle HDLC framing at the BRI S/T interface, and the 68000 core runs the higher-layer protocol stack without burdening bit-level work. Designers typically connect the SCC1 port directly to an external ISDN transceiver (Siemens PSB 2186 or equivalent), dedicating SCC2 and SCC3 to UART console and auxiliary data. The 20 MHz CPU clock provides enough headroom for full LAPD and PPP handling, while the 24-bit address bus maps the entire ISDN signalling memory space without bank switching. Compared with discrete 68000 plus separate SCC chip implementations, the integrated design reduces board area by roughly 40 percent and improves deterministic interrupt latency for real-time ISDN D-channel processing.
Recommended
Industrial Serial Router
The MC68302AG20C's three SCCs allow simultaneous handling of three independent serial links (RS-232/RS-485) for protocol-conversion routing between fieldbus segments. The on-chip RISC communications processor offloads HDLC bit-stuffing and CRC, freeing the 68000 core for routing-table lookups and frame forwarding. Designers use DMA channel 1 to move received SCC frames directly into external SRAM, while the second DMA channel services the transmit side, achieving wire-speed throughput on 38.4 kbps to 2 Mbps serial links. The 1152-byte dual-port RAM is shared with the on-chip communications processor for descriptor passing. The 144-LQFP plastic package supports -40C to +85C industrial temperature operation as documented in NXP legacy datasheets.
