MC68LC302AF20VCT - 20MHz M68K Comm Processor | NXP | 100-LQFP
MPN: MC68LC302AF20VCT ✗ انتهى عمره الإنتاجيMC68LC302AF20VCT نظرة عامة
An integrated multiprotocol processor is a system-on-chip that combines a general-purpose CPU core with dedicated communications hardware for handling serial protocols such as HDLC, UART, and bisync. By collapsing the CPU, DMA engine, serial channels, and memory controller onto one die, an IMP reduces board area, simplifies PCB routing, and shortens firmware debug cycles for embedded network nodes. The MC68LC302 sits in the M683xx product family within NXP's legacy M68000 lineage, and is positioned between the original MC68302 (full-featured) and lower-end members of the LC (low-cost) family.
Key features include a 20 MHz clock speed, three independent full-duplex serial communications controllers supporting HDLC/SDLC, UART, and transparent modes, an on-chip DMA controller with two channels, a DRAM refresh controller, and parallel I/O. The device operates from a 5 V supply and is offered in a 100-pin LQFP (14x14 mm) surface-mount package. Compared to the MC68302, the LC version removes certain advanced features to reduce cost while retaining the same M68000 instruction set for software compatibility.
The architecture is built around the industry-standard MC68000 core executing 16-bit instructions with a 24-bit address space, paired with a RISC communications processor that offloads bit-level protocol work. This dual-engine approach allows the CPU to run higher-layer networking stacks while the CPM handles real-time serial framing, error detection, and DMA-driven buffer management. The result is deterministic throughput on multiple serial links without taxing the main CPU.
Typical applications include ISDN terminal adapters, industrial routers and bridges, frame-relay access devices, low-end protocol converters, and legacy serial multiplexing equipment. The LC variant is especially common in cost-sensitive designs that need M68K software reuse but do not require the full MC68302 feature set.
When designing with this part, ensure that signal-integrity constraints for the 20 MHz bus are met, use proper ground-plane partitioning between the analog serial section and the digital core, and confirm DRAM timing parameters against the chosen memory. Designers migrating from the MC68302 should verify register-level differences in the LC variant before reusing firmware.
This page synthesizes distributor availability, drop-in alternatives, and design notes not found in the manufacturer datasheet alone, giving procurement and engineering teams a single source for sourcing decisions.
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الطرازات في هذه السلسلة
طرازات من نفس السلسلة متوافقة تمامًا مع MC68LC302AF20VCT (نفس عامل الشكل والبصمة) — يختلف في Manufacturer, Part Status.
MC68LC302AF20CT
✅ بديل مباشرتواصل لمعرفة السعر
عرض ورقة البيانات ←MC68LC302PU20VCT
✅ بديل مباشر📋 بديل مرجعي (غير موجود في الكتالوج)
MC68302AF20CT
✅ بديل مباشر📋 بديل مرجعي (غير موجود في الكتالوج)
MC68LC302AF16VCT
✅ بديل مباشر ⚠️ مواصفات غير مُتحقق منهاتواصل لمعرفة السعر
عرض ورقة البيانات ←MC68LC302AF25VCT
✅ بديل مباشر ⚠️ مواصفات غير مُتحقق منها📋 بديل مرجعي (غير موجود في الكتالوج)
MC68LC302AF20VCT الحدود القصوى والخصائص الكهربائية
| Manufacturer | NXP Semiconductors (formerly Freescale, Motorola) |
| Product Type | Integrated Multiprotocol Processor (IMP) |
| Core Processor | M68000 |
| Number of Cores | 1 |
| Core Width | 8/16-Bit |
| Maximum Clock Speed | 20 MHz |
| Co-Processor / DSP | Communications; RISC CPM |
| Series | M683xx |
| العلبة | 100-LQFP (14x14 mm) |
| نوع التركيب | Surface Mount |
| RAM Controllers | DRAM |
| جهد التغذية التشغيلي | 5 V |
| Serial Communications | 3 SCC channels (HDLC/SDLC, UART, transparent) |
| DMA Channels | 2 |
تكوين أطراف MC68LC302AF20VCT
| دبوس 1 | A0 — Address bus bit 0 (or strapping option) |
| دبوس 2 | A1 — Address bus bit 1 |
| دبوس 3 | A2 — Address bus bit 2 |
| دبوس 4 | A3 — Address bus bit 3 |
| دبوس 5 | A4 — Address bus bit 4 |
| دبوس 6 | VCC — +5V power supply |
| دبوس 7 | A5 — Address bus bit 5 |
| دبوس 8 | A6 — Address bus bit 6 |
| دبوس 9 | A7 — Address bus bit 7 |
| دبوس 10 | A8 — Address bus bit 8 |
| دبوس 11 | A9 — Address bus bit 9 |
| دبوس 12 | A10 — Address bus bit 10 |
| دبوس 13 | A11 — Address bus bit 11 |
| دبوس 14 | A12 — Address bus bit 12 |
| دبوس 15 | A13 — Address bus bit 13 |
| دبوس 16 | A14 — Address bus bit 14 |
| دبوس 17 | A15 — Address bus bit 15 |
| دبوس 18 | GND — Ground |
| دبوس 19 | A16 — Address bus bit 16 |
| دبوس 20 | A17 — Address bus bit 17 |
| دبوس 21 | A18 — Address bus bit 18 |
| دبوس 22 | A19 — Address bus bit 19 |
| دبوس 23 | A20 — Address bus bit 20 |
| دبوس 24 | A21 — Address bus bit 21 |
| دبوس 25 | A22 — Address bus bit 22 |
| دبوس 26 | A23 — Address bus bit 23 |
| دبوس 27 | D0 — Data bus bit 0 |
| دبوس 28 | D1 — Data bus bit 1 |
| دبوس 29 | D2 — Data bus bit 2 |
| دبوس 30 | D3 — Data bus bit 3 |
| دبوس 31 | VCC — +5V power supply |
| دبوس 32 | D4 — Data bus bit 4 |
| دبوس 33 | D5 — Data bus bit 5 |
| دبوس 34 | D6 — Data bus bit 6 |
| دبوس 35 | D7 — Data bus bit 7 |
| دبوس 36 | D8 — Data bus bit 8 |
| دبوس 37 | D9 — Data bus bit 9 |
| دبوس 38 | D10 — Data bus bit 10 |
| دبوس 39 | D11 — Data bus bit 11 |
| دبوس 40 | D12 — Data bus bit 12 |
| دبوس 41 | D13 — Data bus bit 13 |
| دبوس 42 | D14 — Data bus bit 14 |
| دبوس 43 | D15 — Data bus bit 15 |
| دبوس 44 | GND — Ground |
| دبوس 45 | BR — Bus Request |
| دبوس 46 | BG — Bus Grant |
| دبوس 47 | BGACK — Bus Grant Acknowledge |
| دبوس 48 | RESET — Reset (active low) |
| دبوس 49 | HALT — Halt (active low) |
| دبوس 50 | CLK — System clock input |
| دبوس 51 | VCC — +5V power supply |
| دبوس 52 | TCLK — Timer clock |
| دبوس 53 | TIN1 — Timer input 1 |
| دبوس 54 | TOUT1 — Timer output 1 |
| دبوس 55 | TIN2 — Timer input 2 |
| دبوس 56 | TOUT2 — Timer output 2 |
| دبوس 57 | IRQ1 — Interrupt request 1 |
| دبوس 58 | IRQ2 — Interrupt request 2 |
| دبوس 59 | IRQ3 — Interrupt request 3 |
| دبوس 60 | IRQ4 — Interrupt request 4 |
| دبوس 61 | IRQ5 — Interrupt request 5 |
| دبوس 62 | IRQ6 — Interrupt request 6 |
| دبوس 63 | GND — Ground |
| دبوس 64 | CS0 — Chip select 0 |
| دبوس 65 | CS1 — Chip select 1 |
| دبوس 66 | CS2 — Chip select 2 |
| دبوس 67 | CS3 — Chip select 3 |
| دبوس 68 | RAS0 — DRAM row address strobe 0 |
| دبوس 69 | RAS1 — DRAM row address strobe 1 |
| دبوس 70 | CAS0 — DRAM column address strobe 0 |
| دبوس 71 | CAS1 — DRAM column address strobe 1 |
| دبوس 72 | VCC — +5V power supply |
| دبوس 73 | WE — Write enable |
| دبوس 74 | OE — Output enable |
| دبوس 75 | TA — Transfer acknowledge |
| دبوس 76 | R/W — Read/Write |
| دبوس 77 | DS — Data strobe |
| دبوس 78 | AS — Address strobe |
| دبوس 79 | GND — Ground |
| دبوس 80 | PA0 — Parallel I/O port A bit 0 |
| دبوس 81 | PA1 — Parallel I/O port A bit 1 |
| دبوس 82 | PA2 — Parallel I/O port A bit 2 |
| دبوس 83 | PA3 — Parallel I/O port A bit 3 |
| دبوس 84 | PA4 — Parallel I/O port A bit 4 |
| دبوس 85 | PA5 — Parallel I/O port A bit 5 |
| دبوس 86 | PA6 — Parallel I/O port A bit 6 |
| دبوس 87 | PA7 — Parallel I/O port A bit 7 |
| دبوس 88 | PB0 — Parallel I/O port B bit 0 |
| دبوس 89 | PB1 — Parallel I/O port B bit 1 |
| دبوس 90 | PB2 — Parallel I/O port B bit 2 |
| دبوس 91 | PB3 — Parallel I/O port B bit 3 |
| دبوس 92 | PB4 — Parallel I/O port B bit 4 |
| دبوس 93 | PB5 — Parallel I/O port B bit 5 |
| دبوس 94 | PB6 — Parallel I/O port B bit 6 |
| دبوس 95 | PB7 — Parallel I/O port B bit 7 |
| دبوس 96 | TXD1 — SCC1 transmit data |
| دبوس 97 | RXD1 — SCC1 receive data |
| دبوس 98 | TXD2 — SCC2 transmit data |
| دبوس 99 | RXD2 — SCC2 receive data |
| دبوس 100 | TXD3/RXD3 — SCC3 transmit/receive data |
التطبيقات النموذجية
MC68LC302AF20VCT مناسب لـ 6 التطبيقs: ISDN Terminal Adapter / NT1, Industrial Router / Bridge, Frame-Relay Access Device (FRAD), Legacy Serial Multiplexer / Concentrator, X.25 Packet Assembler / Disassembler (PAD), POS Terminal / ATM Communications Controller.
ISDN Terminal Adapter / NT1
The MC68LC302AF20VCT is well-suited for ISDN terminal adapters because its RISC CPM handles HDLC framing on the ISDN D-channel autonomously, freeing the M68000 core to run higher-layer protocols. At 20 MHz the core delivers sufficient MIPS for V.120 rate adaptation and PPP multiplexing while the on-chip DMA moves data between serial channels and DRAM buffers without CPU intervention. Three independent SCCs enable simultaneous handling of D-channel, B1/B2 channels, and an external UART for terminal-side command-line interface.
موصى به
Industrial Router / Bridge
For industrial routers and bridges, the MC68LC302AF20VCT offers deterministic multi-protocol serial handling without an external coprocessor. Its three SCCs can terminate HDLC WAN links, RS-232/RS-485 console ports, and a packet-over-sonet channel concurrently, while the M68000 core runs an IP forwarding stack in roughly 1 MIPS throughput per MHz. The integrated DRAM controller eliminates external memory glue logic, simplifying PCB layout in ruggedized industrial enclosures where board area and component count matter for reliability.
موصى به
Frame-Relay Access Device (FRAD)
Frame-relay access devices benefit from the MC68LC302AF20VCT's hardware HDLC/SDLC support, which is the native protocol for frame-relay LAPF framing. At 20 MHz the device can sustain multiple T1/E1 frame-relay channels with the RISC CPM offloading CRC16 and zero-bit-insertion tasks, while the CPU runs the frame-relay PVC management and SNMP agent. The DRAM interface supports burst-mode page accesses typical of FRAD buffer pools, and the chip's low power dissipation suits customer-premises equipment.
موصى به
Legacy Serial Multiplexer / Concentrator
The MC68LC302AF20VCT excels at legacy serial concentration tasks where multiple async UARTs are aggregated onto a higher-speed synchronous link. Each SCC can be configured as a UART (16C750-compatible mode) and the RISC CPM handles DMA-driven buffer fills independent of the main core. This makes the LC302 ideal for industrial telemetry, point-of-sale terminal multiplexers, and SCADA remote-terminal units that must aggregate dozens of slow serial channels without consuming CPU cycles per character.
موصى به
X.25 Packet Assembler / Disassembler (PAD)
X.25 PAD equipment was a flagship application of the original MC68302 family and the MC68LC302AF20VCT inherits that pedigree. The RISC CPM's HDLC support provides ISO/IEC 3309-compliant framing for X.25 Level 2, while the M68000 core runs Level 3 packet assembly, call-setup, and LAPB state machines. The integrated DMA controller manages packet buffers efficiently, making the LC302 a strong fit for legacy X.25 networks in industrial, banking, and government installations still in service today.
موصى به
POS Terminal / ATM Communications Controller
In point-of-sale terminals and ATM communications controllers, the MC68LC302AF20VCT manages dial-up modem links, encrypted PIN-pad interfaces, and back-office WAN connectivity from a single chip. The M68000 core runs the POS application logic while the CPM handles asynchronous serial for the dial modem and synchronous HDLC for the WAN link. At 20 MHz the part delivers the deterministic response times required for payment-processing protocols, and the integrated DRAM controller simplifies the bill-of-materials versus discrete designs.
موصى به
ملخص المنتجات الموصى بها
بيانات مرجعية هندسية لـ MC68LC302AF20VCT — المقارنة وإرشادات التصميم ومعلومات الامتثال.
دليل الاختيار
المقارنة مع البدائل
| المعامل | هذا المنتج | MC68LC302AF20CT | MC68LC302PU20VCT | MC68302AF20CT |
|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Package | 100-LQFP (14x14) | 100-LQFP (14x14) - same | 100-LQFP (14x14) - same | 100-LQFP (14x14) - same |
| Core Processor | M68000 | M68000 | M68000 | M68000 |
| Clock Speed | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Core Width | 8/16-Bit | 8/16-Bit | 8/16-Bit | 8/16-Bit |
| Feature Set | Low-Cost (LC) | Low-Cost (LC) | Low-Cost (LC) | Full feature |
| SCC Channels | 3 | 3 | 3 | 3 |
| Packaging | Tray (VCT) | Tape & Reel (CT) | Tray, PQFP package | Tape & Reel (CT) |
أبرز الفروقات
- Lowest-cost variant of MC68302 in 100-LQFP footprint (مقابلMC68302AF20CT)
- Tray packaging (VCT) for low-volume and prototype builds (مقابلMC68LC302AF20CT)
- Same 100-LQFP AF footprint across LC and full feature families (مقابلMC68LC302PU20VCT)
ملاحظات التصميم
The MC68LC302AF20VCT operates from a single +5V supply and draws peak current during DRAM refresh bursts; bulk-decouple VCC pins (6, 31, 51, 72) with 10uF tantalum plus 0.1uF ceramic per pin to prevent bus-cycle voltage droops. Connect all VCC and GND pins (18, 44, 63, 79) directly to power planes; do not daisy-chain. Estimated local decoupling budget is 4 capacitors total on a 4-layer PCB, which is sufficient for 20 MHz operation.
Lay out the 100-LQFP package on a 4-layer PCB with continuous ground plane beneath the device. Keep the CLK trace (pin 50) short and matched-length with TCLK (pin 52) to avoid skew; use a clock-oscillator module with CMOS output drive. Route the parallel data bus D0-D15 (pins 27-43) as a matched-length group with series damping resistors if bus length exceeds 50 mm to control ringing on the 20 MHz bus.
Confirm whether your design requires the MC68LC302 (low-cost) or full MC68302 before sourcing, as register-level differences exist in the SCC, timer, and parallel I/O blocks. Pin-compatible in the same 100-LQFP package, the MC68302 adds features but the LC302 firmware is not always binary-compatible; consult the MC68LC302/D datasheet register appendix before reusing code. Always order factory-traceable parts from authorized distributors because counterfeit risk is elevated for legacy NXP/Motorola M68K parts.
The address bus A1-A23 (pins 1-5, 7-17, 19-26) and data bus D0-D15 (pins 27-30, 32-43) should be routed with controlled impedance of 50-70 ohms to ground. Place source-series termination resistors (22-33 ohm) on the address and data buses at the M68LC302 driver end if the load is concentrated. Failure to terminate results in significant overshoot on the 20 MHz bus that can corrupt reads from external peripherals.
معلومات الامتثال
Compliance status not explicitly stated in the verified distributor data. The MC68LC302AF20VCT is a legacy M68K part originally released in the 1990s; consult NXP's product compliance documentation directly for current RoHS/REACH status before use in new designs.