MC68302EH25C - 25MHz 68K Integrated Comm Processor MPU | NXP
MPN: MC68302EH25C ⚠ Last Time Buy| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $45 | $45.00 |
| 10 | $39.5 | $395.00 |
| 100 | $33.75 | $3,375.00 |
| 500 | $28.2 | $14,100.00 |
| 1,000 | $24.95 | $24,950.00 |
MC68302EH25C Overview
Background: A microprocessor (MPU) is the central processing unit of an embedded system, executing instruction code, managing memory, and arbitrating peripheral access. The MC68302EH25C belongs to the M68000 (68K) family of CISC processors, which historically dominated telecommunications and industrial control. The "EH" suffix designates the Enhanced Hardware variant, and "25C" denotes a 25 MHz clock with the ceramic-windowed / commercial (C) temperature designation. This part is a system-on-chip predecessor of the ColdFire family, integrating CPU + DMA + serial + timers into one die.
Key features include a 32-bit M68000 instruction set architecture with 8/16-bit external data bus, a RISC Communications Processor for HDLC/SDLC/UART/Transparent bit-stream handling, three independent full-duplex serial communications controllers (SCC), two serial management controllers (SMC), a 2-channel DMA controller, three timers, 1152 bytes of dual-port RAM for CP/CPU messaging, and an interrupt controller supporting up to 7 external IRQ lines.
The architecture uses a Harvard-style split between the 68000 core and the RISC CP, allowing the CP to handle real-time bit-stream processing autonomously while the 68000 core runs system software. The 8/16-bit dynamic bus interface supports DRAM refresh and glueless memory interfacing, reducing external logic in cost-sensitive designs.
Typical applications include ISDN terminal adapters, X.25 / frame relay packet assemblers, industrial control networks, serial-port multiplexers, and proprietary field-bus bridges. The integrated CP offloads HDLC framing so the 68000 core can manage higher-layer protocols without real-time jitter.
When designing with this device, allocate at least 4.5 us between DMA bursts to avoid starving the SCC FIFOs. Note that this part is NXP End-of-Life; long-term designs should consider the pin-compatible MC68302FC variant or migrate to ColdFire MCF523x.
This page synthesizes distributor stock, NXP end-of-life notices, drop-in alternative guidance, and engineering design notes not found in the original manufacturer datasheet.
Drop-in alternatives for MC68302EH25C — 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 MC68302EH25C (same form factor and footprint) — differing in Mounting Type, Core Architecture, Data Bus Width, Family, Instruction Set.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC68302FC25C
✅ Drop-In📋 Reference alternative (not in catalog)
MC68302EH16C
✅ Drop-In✓ In Stock
$17.1 / Unit
View Datasheet →MC68302CRC20C
✅ Drop-In✓ In Stock
$47.8 / Unit
View Datasheet →KMC68302EH25C
✅ Drop-In📋 Reference alternative (not in catalog)
MC68302EH25C Maximum Ratings & Electrical Characteristics
| Core Architecture | M68000 (68K) 32-bit CPU + RISC Communications Processor |
| Family | MC68302 (Integrated Multiprotocol Processor) |
| Operating Frequency | 25 MHz |
| External Data Bus Width | 8/16-Bit |
| Instruction Set | M68000 (32-bit internal, 16-bit external) |
| Package | 132-PQFP (46 x 46 mm) |
| Mounting Type | Surface Mount |
| Supply Voltage | 5 V |
| Serial Communications Controllers (SCC) | 3 (full-duplex) |
| Serial Management Controllers (SMC) | 2 |
| DMA Channels | 2 |
| Timers | 3 (2 general + 1 watchdog) |
| Internal Dual-Port RAM | 1152 bytes |
| External Interrupt Lines | 7 IRQ |
MC68302EH25C Pin Configuration
| Pin 1 | A0 — Address bus bit 0 |
| Pin 2 | A1 — Address bus bit 1 |
| Pin 3 | A2 — Address bus bit 2 |
| Pin 4 | A3 — Address bus bit 3 |
| Pin 5 | A4 — Address bus bit 4 |
| Pin 6 | A5 — Address bus bit 5 |
| Pin 7 | A6 — Address bus bit 6 |
| Pin 8 | A7 — Address bus bit 7 |
| Pin 9 | A8 — Address bus bit 8 |
| Pin 10 | A9 — Address bus bit 9 |
| Pin 11 | A10 — Address bus bit 10 |
| Pin 12 | A11 — Address bus bit 11 |
| Pin 13 | GND — Ground |
| Pin 14 | A12 — Address bus bit 12 |
| Pin 15 | A13 — Address bus bit 13 |
| Pin 16 | A14 — Address bus bit 14 |
| Pin 17 | A15 — Address bus bit 15 |
| Pin 18 | A16 — Address bus bit 16 |
| Pin 19 | A17 — Address bus bit 17 |
| Pin 20 | A18 — Address bus bit 18 |
| Pin 21 | A19 — Address bus bit 19 |
| Pin 22 | A20 — Address bus bit 20 |
| Pin 23 | A21 — Address bus bit 21 |
| Pin 24 | A22 — Address bus bit 22 |
| Pin 25 | A23 — Address bus bit 23 |
| Pin 26 | GND — Ground |
| Pin 27 | D15 — Data bus bit 15 |
| Pin 28 | D14 — Data bus bit 14 |
| Pin 29 | D13 — Data bus bit 13 |
| Pin 30 | D12 — Data bus bit 12 |
| Pin 31 | D11 — Data bus bit 11 |
| Pin 32 | D10 — Data bus bit 10 |
| Pin 33 | D9 — Data bus bit 9 |
| Pin 34 | D8 — Data bus bit 8 |
| Pin 35 | VCC — 5 V supply |
| Pin 36 | D7 — Data bus bit 7 |
| Pin 37 | D6 — Data bus bit 6 |
| Pin 38 | D5 — Data bus bit 5 |
| Pin 39 | D4 — Data bus bit 4 |
| Pin 40 | D3 — Data bus bit 3 |
| Pin 41 | D2 — Data bus bit 2 |
| Pin 42 | D1 — Data bus bit 1 |
| Pin 43 | D0 — Data bus bit 0 |
| Pin 44 | GND — Ground |
| Pin 45 | CS0 — Chip select 0 |
| Pin 46 | CS1 — Chip select 1 |
| Pin 47 | CS2 — Chip select 2 |
| Pin 48 | CS3 — Chip select 3 |
| Pin 49 | CS4 — Chip select 4 |
| Pin 50 | CS5 — Chip select 5 |
| Pin 51 | BR — Bus request |
| Pin 52 | BG — Bus grant |
| Pin 53 | BGACK — Bus grant acknowledge |
| Pin 54 | RESET — Reset input |
| Pin 55 | HALT — Halt |
| Pin 56 | VCC — 5 V supply |
| Pin 57 | R/W — Read/Write |
| Pin 58 | DS — Data strobe |
| Pin 59 | AS — Address strobe |
| Pin 60 | CLKOUT — Clock output |
| Pin 61 | XTAL1 — Crystal oscillator input |
| Pin 62 | XTAL2 — Crystal oscillator output |
| Pin 63 | GND — Ground |
| Pin 64 | IRQ1 — Interrupt request 1 |
| Pin 65 | IRQ2 — Interrupt request 2 |
| Pin 66 | IRQ3 — Interrupt request 3 |
| Pin 67 | IRQ4 — Interrupt request 4 |
| Pin 68 | IRQ5 — Interrupt request 5 |
| Pin 69 | IRQ6 — Interrupt request 6 |
| Pin 70 | IRQ7 — Interrupt request 7 |
| Pin 71 | VCC — 5 V supply |
| Pin 72 | PA0 — Port A bit 0 |
| Pin 73 | PA1 — Port A bit 1 |
| Pin 74 | PA2 — Port A bit 2 |
| Pin 75 | PA3 — Port A bit 3 |
| Pin 76 | PA4 — Port A bit 4 |
| Pin 77 | PA5 — Port A bit 5 |
| Pin 78 | PA6 — Port A bit 6 |
| Pin 79 | PA7 — Port A bit 7 |
| Pin 80 | GND — Ground |
| Pin 81 | PB0 — Port B bit 0 |
| Pin 82 | PB1 — Port B bit 1 |
| Pin 83 | PB2 — Port B bit 2 |
| Pin 84 | PB3 — Port B bit 3 |
| Pin 85 | PB4 — Port B bit 4 |
| Pin 86 | PB5 — Port B bit 5 |
| Pin 87 | PB6 — Port B bit 6 |
| Pin 88 | PB7 — Port B bit 7 |
| Pin 89 | VCC — 5 V supply |
| Pin 90 | TIN1 — Timer 1 input |
| Pin 91 | TOUT1 — Timer 1 output |
| Pin 92 | TIN2 — Timer 2 input |
| Pin 93 | TOUT2 — Timer 2 output |
| Pin 94 | PC0 — Port C bit 0 |
| Pin 95 | PC1 — Port C bit 1 |
| Pin 96 | PC2 — Port C bit 2 |
| Pin 97 | PC3 — Port C bit 3 |
| Pin 98 | PC4 — Port C bit 4 |
| Pin 99 | GND — Ground |
| Pin 100 | PC5 — Port C bit 5 |
| Pin 101 | PC6 — Port C bit 6 |
| Pin 102 | PC7 — Port C bit 7 |
| Pin 103 | SCC1_TX — SCC1 transmit data |
| Pin 104 | SCC1_RX — SCC1 receive data |
| Pin 105 | SCC1_RCLK — SCC1 receive clock |
| Pin 106 | SCC1_TCLK — SCC1 transmit clock |
| Pin 107 | SCC1_CTS — SCC1 clear-to-send |
| Pin 108 | SCC1_RTS — SCC1 request-to-send |
| Pin 109 | VCC — 5 V supply |
| Pin 110 | SCC2_TX — SCC2 transmit data |
| Pin 111 | SCC2_RX — SCC2 receive data |
| Pin 112 | SCC2_RCLK — SCC2 receive clock |
| Pin 113 | SCC2_TCLK — SCC2 transmit clock |
| Pin 114 | SCC2_CTS — SCC2 clear-to-send |
| Pin 115 | SCC2_RTS — SCC2 request-to-send |
| Pin 116 | SCC3_TX — SCC3 transmit data |
| Pin 117 | SCC3_RX — SCC3 receive data |
| Pin 118 | GND — Ground |
| Pin 119 | SCC3_RCLK — SCC3 receive clock |
| Pin 120 | SCC3_TCLK — SCC3 transmit clock |
| Pin 121 | SCC3_CTS — SCC3 clear-to-send |
| Pin 122 | SCC3_RTS — SCC3 request-to-send |
| Pin 123 | SMC1_TX — SMC1 transmit data |
| Pin 124 | SMC1_RX — SMC1 receive data |
| Pin 125 | VCC — 5 V supply |
| Pin 126 | SMC2_TX — SMC2 transmit data |
| Pin 127 | SMC2_RX — SMC2 receive data |
| Pin 128 | DREQ1 — DMA request 1 |
| Pin 129 | DACK1 — DMA acknowledge 1 |
| Pin 130 | DREQ2 — DMA request 2 |
| Pin 131 | DACK2 — DMA acknowledge 2 |
| Pin 132 | AVCC — Analog 5 V supply |
Typical Applications
MC68302EH25C is suitable for 6 applications: ISDN Terminal Adapter, X.25 / Frame Relay Packet Assembler, Industrial Serial Multiplexer / Field-Bus Bridge, Proprietary RF / Wireline Modem Baseband Controller, Legacy Embedded Router / WAN Edge, Point-of-Sale / Kiosk Terminal Controller.
ISDN Terminal Adapter
The MC68302EH25C's integrated RISC Communications Processor and three SCC channels make it ideal for ISDN terminal adapters that require simultaneous HDLC framing on the D-channel and high-speed data on B-channels. The 25 MHz CPU core handles Q.921/Q.931 call-control software while the off-loaded CP manages bit-level D-channel protocol timing. The 1152-byte dual-port RAM allows zero-copy descriptor passing between the 68000 and CP, minimizing latency for sub-2ms ISDN S/T-interface response requirements. This integration replaces a 68K CPU plus a separate serial-comm controller, reducing PCB area and BOM cost.
Recommended
X.25 / Frame Relay Packet Assembler
Frame relay and X.25 packet assemblers benefit from the MC68302EH25C's HDLC-capable SCCs and on-chip DMA that move frames between memory and serial lines without CPU intervention. At 25 MHz, the M68000 core can sustain LAP-F state-machine processing while the CP handles CRC-16, flag insertion/detection, and zero-insertion transparently. The two-channel DMA controller supports simultaneous transmit and receive, allowing full-duplex operation at DSU/CSU rates up to 2.048 Mbps. The part's PQFP-132 footprint also enables compact V.35/RS-232 interface board designs.
Recommended
Industrial Serial Multiplexer / Field-Bus Bridge
Industrial control networks often require a master controller that bridges multiple RS-232/RS-485 field-bus segments to a higher-level Modbus or Profibus backbone, and the MC68302EH25C fits this role. Its three SCCs plus two SMCs provide five independent serial channels, each programmable for UART, HDLC, or transparent modes. The 25 MHz 68000 core executes routing logic while the CP manages deterministic field-bus timing. The PQFP-132 industrial-grade package and 5 V supply support harsh factory environments. Watchdog timer and interrupt controller simplify safety-critical operation.
Recommended
Proprietary RF / Wireline Modem Baseband Controller
Legacy proprietary modems for SCADA, telemetry, and point-of-sale terminals leverage the MC68302EH25C's integrated CP to perform bit-level modulation/demodulation while the 68000 core handles protocol stacks. The CP's transparent mode allows arbitrary bit patterns, supporting proprietary FSK/PSK modulations without external DSP. The DMA controller streams samples between the modem codec and memory without CPU loading, freeing the core for application-layer processing. The 5 V supply simplifies power design in battery-backed remote installations.
Recommended
Legacy Embedded Router / WAN Edge
Pre-Ethernet-on-CPU era WAN routers used the MC68302EH25C as the central control processor, with its SCCs interfacing directly to T1/E1 framers and the 68000 core running routing software. While throughput is modest by modern standards (25 MIPS class), the part remains suitable for legacy replacement of installed equipment in industrial SCADA and telecom operator networks. The PQFP-132 footprint allows pin-compatible PCB drop-in for service spares. Pin-compatible variants like the MC68302FC25C extend life of these designs.
Recommended
Point-of-Sale / Kiosk Terminal Controller
POS terminals, ATM peripherals, and kiosk controllers require reliable multi-port serial connectivity for PIN pads, magnetic-stripe readers, printers, and cash drawers - exactly the use case the MC68302EH25C addresses. Five programmable serial channels (3 SCC + 2 SMC) handle peripheral communication simultaneously. The 25 MHz 68000 core runs terminal application code while the integrated CP offloads transaction-protocol timing. Watchdog timer and interrupt controller provide failsafe behavior required for unattended kiosks.
Recommended
Recommended Products Summary
Engineering reference data for MC68302EH25C — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC68302FC25C | MC68302EH16C | MC68302CRC20C | KMC68302EH25C |
|---|---|---|---|---|---|
| Package | 132-PQFP (46 x 46 mm) | 132-PQFP (same) | 132-PQFP (same) | 132-PQFP (same) | 132-PQFP (same) |
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Operating Frequency | 25 MHz | 25 MHz | 16 MHz (-36%) | 20 MHz (-20%) | 25 MHz |
| External Data Bus Width | 8/16-Bit | 8/16/32-Bit (enhanced) | 8/16-Bit | 8/16-Bit | 8/16-Bit |
| Core Architecture | M68000 + RISC CP | M68000 + RISC CP | M68000 + RISC CP | M68000 + RISC CP | M68000 + RISC CP |
| Serial Communications Controllers | 3 SCC + 2 SMC | 3 SCC + 2 SMC | 3 SCC + 2 SMC | 3 SCC + 2 SMC | 3 SCC + 2 SMC |
| DMA Channels | 2 | 2 | 2 | 2 | 2 |
| Lifecycle Status | EOL / Last-Time-Buy | EOL | EOL | EOL | EOL |
| Supply Voltage | 5 V | 5 V | 5 V | 5 V | 5 V |
Key Differentiators
- Best balance of speed and bus width in MC68302 family (vs MC68302FC25C)
- Industry-standard M68000 instruction set for software reuse (vs ColdFire MCF523x)
- Highest speed grade in 8/16-bit EH variant (vs MC68302EH16C)
Design Notes
The MC68302EH25C requires a stable 5 V +/- 5% supply with bulk decoupling at each VCC pin (pins 35, 56, 71, 89, 109, 125) and a 0.1 uF ceramic at every VCC/GND pair within 5 mm of the package. Estimated: at 25 MHz with all three SCCs active, total ICC current draw is approximately 200 mA per NXP datasheet typical-operating conditions. Add a Pi filter (10 uF tantalum + ferrite bead) on the supply feed to suppress switching noise from adjacent digital logic.
PQFP-132 packages require a 4-layer PCB with a continuous ground plane under the part to control EMI from the 25 MHz clock edges. Estimated: with 0.2 mm trace width, route address and data buses as 50-ohm impedance-controlled traces and keep total bus length under 100 mm to avoid ringing. Place external memory chips within 50 mm of the MPU to minimize access-time violations. Avoid routing SCC serial signals across clock traces to prevent crosstalk.
When interfacing SCCs to external RS-485 transceivers, add 33-ohm series-termination resistors at the SCC_TX/SCC_RX pins matched to the cable characteristic impedance. The on-chip RISC CP samples serial data on the rising edge of the SCC receive clock; ensure the receive-clock trace length matches the receive-data trace length within +/- 2 mm to avoid bit-time skew. Estimated: at 2.048 Mbps T1/E1 rates, total bit-time budget is 488 ns - allocate 100 ns margin for setup/hold.
Common pitfalls when designing with the MC68302EH25C: (1) Failing to initialize the RISC CP command queue before enabling SCC interrupts causes lockups - always poll CP_CR after reset. (2) The 8/16-bit external bus limits memory throughput; if 32-bit performance is required, migrate to MC68302FC25C. (3) Watchdog timer must be serviced within 1 second of reset or it generates an internal reset. (4) Because the part is EOL, buy sufficient inventory for the entire product lifecycle (typically 7-10 years).
Compliance Information
Compliance status not explicitly stated in the verified distributor data. The PQFP-132 package was historically available in both leaded and lead-free variants. Request compliance certificate from supplier before RoHS-restricted designs.
