MC68302EH16C - 16MHz M683xx Multi-Protocol Com Proc | NXP
MPN: MC68302EH16C ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $28.5 | $28.50 |
| 10 | $25.2 | $252.00 |
| 100 | $22.85 | $2,285.00 |
| 500 | $19.4 | $9,700.00 |
| 1,000 | $17.1 | $17,100.00 |
MC68302EH16C Overview
An MPU (Microprocessor Unit) is a CPU-centric chip without on-chip non-volatile program memory, historically used as the host processor in deeply embedded designs such as routers, ISDN terminals, and industrial controllers. Within the broader taxonomy, the MC68302 sits one level below a full system-on-chip: it is an MPU plus dedicated communications silicon, which predates the modern SoC era by combining peripheral integration with deterministic M68000 firmware execution.
Headline specifications include a 16.67 MHz maximum bus/clock, 16-bit data bus with 8-bit dynamic bus sizing, a 32-bit instruction set with extensive addressing modes, and a 2.7 V to 5.5 V tolerant I/O interface. Internal peripherals include three serial communications controllers (SCCs) supporting HDLC/SDLC, UART, and BISYNC, two serial management controllers (SMCs) for lower-speed serial channels, a 2-channel DMA engine, and a 2K-byte system integration block for chip-select and bus arbitration.
This part is fabricated on a mature CMOS process and integrates 1,152 bytes of dual-port RAM for buffer descriptors and stacks, eliminating external SRAM in many low-channel-count designs. A hardware interrupt controller with 7 priority levels supports nested interrupts. The 132-pin PQFP package provides mature surface-mount manufacturability, while the part is specified across the 0 to +70C commercial temperature range and is fully static for clock-throttling flexibility.
Typical applications include multi-protocol serial routers, ISDN terminal adapters, X.25 / frame relay access multiplexers, low-end industrial protocol bridges, and legacy telecom control boards. Designers choose this part when they need the M68000 toolchain, deterministic interrupt response, and on-chip HDLC/UART channels.
When designing with the MC68302EH16C, provision adequate decoupling on the 5 V and 3.3 V rails and route the parallel bus with controlled-impedance traces. Note the part's lifecycle: this is a discontinued/EOL product per the NXP product page, so second-source alternatives and stocking strategies should be validated before committing the design.
Drop-in alternatives for MC68302EH16C — 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 MC68302EH16C (same form factor and footprint) — differing in Instruction Set, Family, Maximum Clock Frequency, Package, Data Bus Width.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC68302CEH16C
✅ Drop-In✓ In Stock
$49.9 / Unit
View Datasheet →MC68302EH16CR2
✅ Drop-In📋 Reference alternative (not in catalog)
MC68302EH25C
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$24.95 / Unit
View Datasheet →MC68302EH20C
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$19.85 / Unit
View Datasheet →MC68EN302EH16C
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
MC68302EH16C Maximum Ratings & Electrical Characteristics
| Core | M68000 (M683xx series, 1 core) |
| Data Bus Width | 8/16-bit (with dynamic bus sizing) |
| Instruction Set | M68000 32-bit ISA |
| Maximum Clock Frequency | 16 MHz (16.67 MHz) |
| Performance | 1.1 MIPS at 16 MHz |
| Operating Supply Voltage | 4.75 V to 5.25 V (core) / 3.0 V to 3.6 V tolerant I/O |
| On-chip Peripherals | 3x SCC (HDLC/UART/BISYNC), 2x SMC, 2-ch DMA, 2K SysInt, interrupt controller |
| Internal RAM | 1152 bytes dual-port |
| DMA Channels | 2 |
| Serial Communication Controllers | 3 (full HDLC/SDLC/UART) |
| Serial Management Controllers | 2 |
| Interrupt Levels | 7 priority levels, nested interrupt support |
| Package | 132-PQFP (46 x 46 mm) |
| Mounting Type | Surface Mount |
| Operating Temperature | 0C to +70C (commercial) |
| Family | MC68302 Multi-Protocol Communications Processor |
MC68302EH16C Pin Configuration
| Pin 1 | A23 — Address bus bit 23 |
| Pin 10 | A14 — Address bus bit 14 |
| Pin 20 | A7 — Address bus bit 7 |
| Pin 30 | D0 — Data bus bit 0 |
| Pin 40 | D11 — Data bus bit 11 |
| Pin 50 | IRQ7 — Interrupt request 7 (highest priority) |
| Pin 60 | RMC — Read-Modify-Write for bit manipulation |
| Pin 70 | TIN1 — Timer 1 input |
| Pin 80 | RTS3 — SCC3 request to send |
| Pin 90 | TXD3 — SCC3 transmit data |
| Pin 100 | VCC — +5 V power supply |
| Pin 110 | GND — Ground reference |
| Pin 120 | GND — Ground reference |
| Pin 130 | RESET — System reset (active low) |
| Pin 132 | HALT — Halt control (with debug) |
Typical Applications
MC68302EH16C is suitable for 6 applications: HDLC Frame Relay Access Multiplexer, ISDN Terminal Adapter, Industrial Serial Protocol Bridge, X.25 Packet Assembler/Disassembler, Legacy Telecom Control Board, Embedded Routers and Bridges.
HDLC Frame Relay Access Multiplexer
The MC68302EH16C is a natural fit for HDLC frame relay access multiplexers because all three on-chip SCCs independently support HDLC/SDLC framing at 16 MHz with zero host CPU overhead per bit, offloading up to 3 T1/E1 physical channels directly from the M68000 core. The 1,152-byte dual-port RAM holds frame descriptors and T1/E1 HDLC controllers, while the 2-channel DMA streams payload bytes to external SDRAM at non-intrusive bus cycles. This integration beats an external UART+ASIC pair on BOM cost for legacy FRAD designs. Designers typically wire SCC1 to a 2.048 MHz T1 line at full RS-422 differential drive strength and use 10 MHz of the 16 MHz core for synchronization.
Recommended
ISDN Terminal Adapter
An ISDN terminal adapter benefits from the MC68302EH16C's two SMCs and three SCCs: SCC1/SCC2 carry D-channel HDLC traffic on the BRI S/T interface, while SCC3 handles synchronous V.120 or PPP framing in the B1/B2 channels. The 16 MHz M68000 core executes Layer 3 firmware (PPP, Multilink PPP, IPCP) with 1.1 MIPS sustained throughput, and the 2-channel DMA aggregates B-channels into a 128 kbps USB or RS-232 host uplink. Compared with newer ARM Cortex-M0 solutions, the M68000 gives deterministic interrupt response with 7-level priority. The 132 PQFP keeps the adapter card to a 4-layer 60x100 mm PCB with all routing on the top side.
Recommended
Industrial Serial Protocol Bridge
The MC68302EH16C bridges legacy RS-422/RS-485 industrial protocols (Modbus RTU, DF1, Profibus-slave) to Ethernet or CAN because the three SCCs each handle independent UART or HDLC frames asynchronously while the DMA shuttles octets to a memory-mapped protocol stack. The mature M68000 toolchain allows deterministic 16-bit address/8-bit data bus designs that fit into 2 KB of EPROM with a small footprint. The 132 PQFP survives 0 to +70C operation, and at 16 MHz worst-case interrupt latency of 19 cycles (~1.2 microseconds) is well under the Modbus 1.75 ms character timeout. Designers wire an external MAX3162 or SN65LBC184 RS-485 transceiver to SCC1.
Recommended
X.25 Packet Assembler/Disassembler
X.25 PADs deploy the MC68302EH16C at the network side because the M68000 core can implement the full X.25 LAPB state machine while SCC1/SCC2/SCC3 drive three HDLC links, each at 64 kbps through DSU/CSU transformers. The 1,152-byte dual-port RAM buffers LAPD frames between channel firmware and the host PC, and the 2-channel DMA streams 128-byte payloads while the MPU runs X.25 packetisation. The chip's mature PAL firmware outperforms newer RISC cores on 8-bit bus designs, reducing total BOM by 1 to 2 dollars per port. The 132 PQFP also provides the deterministic latency required by X.25 supervisory timers (T1/T2/T3).
Recommended
Legacy Telecom Control Board
Central-office telecom control boards use the MC68302EH16C as a distributed processor running the M68000 firmware that drives SS7 link layer, V.120 rate adaption, or SDLC signaling channels. The 132 PQFP distributes power and ground across all four edges for noise immunity in dense backplane designs, and the 7-priority-level interrupt controller handles multiple signaling tasks deterministically. Compared with a PowerQUICC solution, the M68000 ISA gives easier integration with existing telecom firmware libraries dating to the 1990s. Designers pair this MPU with an external SS7 transceiver and a bus-arbitrated multi-drop backplane.
Recommended
Embedded Routers and Bridges
Low-end routers and protocol bridges in industrial automation benefit from the MC68302EH16C's three SCCs and 16-bit M68000 core because the chip can run an IP forwarding loop on three WAN interfaces simultaneously without external bridge ASICs. The 16 MHz core sustains 1.1 MIPS, enough to forward <3 Mbps of aggregate payload at 64-byte packets, and the 1,152-byte dual-port RAM holds routing tables for small routing tables. The 132 PQFP fits a fan-out card design with no BGA escapes. Compared with newer Cortex-M0 + ENC28J60 stacks, this part keeps legacy IP firmware and bootloaders running.
Recommended
Recommended Products Summary
Engineering reference data for MC68302EH16C — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC68302CEH16C | MC68302EH16CR2 | MC68302EH25C | MC68302EH20C | MC68EN302EH16C |
|---|---|---|---|---|---|---|
| Brand | NXP Semiconductors (formerly Freescale) | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Package | 132-PQFP (46x46 mm) | 132-PQFP (46x46 mm) - same | 132-PQFP (46x46 mm) - same | 132-PQFP (46x46 mm) - same | 132-PQFP (46x46 mm) - same | 132-PQFP (46x46 mm) - same |
| Core Clock | 16 MHz | 16 MHz | 16 MHz | 25 MHz (+56%) | 20 MHz (+25%) | 16 MHz |
| SCC Channels | 3 HDLC/UART | 3 HDLC/UART | 3 HDLC/UART | 3 HDLC/UART | 3 HDLC/UART | 3 HDLC/UART + Ethernet |
| On-chip RAM | 1152 bytes dual-port | 1152 bytes dual-port | 1152 bytes dual-port | 1152 bytes dual-port | 1152 bytes dual-port | 1152 bytes dual-port |
| DMA Channels | 2 | 2 | 2 | 2 | 2 | 2 |
| Operating Voltage | 5 V core | 5 V core | 5 V core | 5 V core | 5 V core | 5 V core |
| Lifecycle Status | End of Life | End of Life | End of Life | End of Life | End of Life | End of Life |
Key Differentiators
- Drop-in replacement without firmware change (vs MC68302CEH16C)
- Adds on-chip 10 Mbps Ethernet MAC (vs MC68EN302EH16C)
- Speed upgrade within same footprint (vs MC68302EH25C)
Design Notes
Estimated power dissipation at 16 MHz core clock and 5 V supply is approximately 500 mW (typical) for the MC68302EH16C. Each VCC/GND pin pair on the 132 PQFP should be decoupled with a 0.1 microfarad ceramic plus a 10 microfarad tantalum in parallel, placed within 5 mm of each pad pair. Multiple decoupling sites reduce the high-frequency supply noise from the parallel bus switching.
The 132-PQFP package has a theta_JA of approximately 35 C/W on a 4-layer JEDEC test board with no airflow. At 0.5 W dissipation under the worst-case 70 C ambient, junction temperature rises about 17.5 C, keeping Tj well under 125 C. Forced-air cooling is recommended in sealed enclosures where ambient exceeds 60 C, and unused pins should be tied inactive to reduce bus driver current.
Route the parallel address/data bus with 50 ohm controlled impedance traces on a 4-layer board, keeping the bus traces together to minimize skew. SCC1/SCC2/SCC3 differential pairs (TXD/RXD plus clock) should be routed as 100 ohm differential and length-matched within 5 mm. Place the bus arbiter logic near the address latch and termination resistors for bus clock distribution.
A common layout mistake is to use a 5 V-only external EPROM when the M68000 bus expects 3.3 V-tolerant signals; verify that the boot EPROM matches the bus voltage. Another is misconfiguring the BAR/BR cycle length during long bus accesses, which corrupts arbitration. Always issue the bootstrap sequence from the BERR/restart handler before enabling SCC interrupts.
Series-terminate the SCC driver outputs with 22 to 33 ohms at the MC68302EH16C pin to suppress reflections when the device drives long bus stubs. Use an oscilloscope to measure the rising edge at the SCC load: overshoot should be below 0.5 V on a 5 V signal. JTAG scan path integrity is critical if you use hardware single-step debug: keep the JTAG trace under 50 mm and avoid stubs.
Compliance Information
Distributor data does not explicitly state RoHS, REACH, or lead-free status for this EOL part. AEC-Q100 is not applicable since this is a commercial-grade legacy MPU.
