MC68LC302AF20VCT - 20MHz M68K Comm Processor | NXP | 100-LQFP
MPN: MC68LC302AF20VCT ✗ Cuối đờiMC68LC302AF20VCT Tóm tắt
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.
Bộ thay thế dễ dàng lắp đặt cho MC68LC302AF20VCT — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
Các biến thể trong loạt này
Các mẫu cùng loạt có thể lắp đặt dễ dàng tương thích với MC68LC302AF20VCT (cùng hình factor và footprint) — khác nhau ở Manufacturer, Part Status.
MC68LC302AF20CT
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →MC68LC302PU20VCT
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
MC68302AF20CT
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
MC68LC302AF16VCT
✅ Drop-In ⚠️ Thông số chưa được xác minhLiên hệ để biết giá
Xem tài liệu →MC68LC302AF25VCT
✅ Drop-In ⚠️ Thông số chưa được xác minh📋 Tham chiếu thay thế (không có trong danh mục)
MC68LC302AF20VCT Tỷ lệ tối đa & tính chất điện
| 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 |
| Hộp | 100-LQFP (14x14 mm) |
| Kiểu lắp đặt | Surface Mount |
| RAM Controllers | DRAM |
| Điện áp cung cấp hoạt động | 5 V |
| Serial Communications | 3 SCC channels (HDLC/SDLC, UART, transparent) |
| DMA Channels | 2 |
Cấu hình chân MC68LC302AF20VCT
| Chân 1 | A0 — Address bus bit 0 (or strapping option) |
| Chân 2 | A1 — Address bus bit 1 |
| Chân 3 | A2 — Address bus bit 2 |
| Chân 4 | A3 — Address bus bit 3 |
| Chân 5 | A4 — Address bus bit 4 |
| Chân 6 | VCC — +5V power supply |
| Chân 7 | A5 — Address bus bit 5 |
| Chân 8 | A6 — Address bus bit 6 |
| Chân 9 | A7 — Address bus bit 7 |
| Chân 10 | A8 — Address bus bit 8 |
| Chân 11 | A9 — Address bus bit 9 |
| Chân 12 | A10 — Address bus bit 10 |
| Chân 13 | A11 — Address bus bit 11 |
| Chân 14 | A12 — Address bus bit 12 |
| Chân 15 | A13 — Address bus bit 13 |
| Chân 16 | A14 — Address bus bit 14 |
| Chân 17 | A15 — Address bus bit 15 |
| Chân 18 | GND — Ground |
| Chân 19 | A16 — Address bus bit 16 |
| Chân 20 | A17 — Address bus bit 17 |
| Chân 21 | A18 — Address bus bit 18 |
| Chân 22 | A19 — Address bus bit 19 |
| Chân 23 | A20 — Address bus bit 20 |
| Chân 24 | A21 — Address bus bit 21 |
| Chân 25 | A22 — Address bus bit 22 |
| Chân 26 | A23 — Address bus bit 23 |
| Chân 27 | D0 — Data bus bit 0 |
| Chân 28 | D1 — Data bus bit 1 |
| Chân 29 | D2 — Data bus bit 2 |
| Chân 30 | D3 — Data bus bit 3 |
| Chân 31 | VCC — +5V power supply |
| Chân 32 | D4 — Data bus bit 4 |
| Chân 33 | D5 — Data bus bit 5 |
| Chân 34 | D6 — Data bus bit 6 |
| Chân 35 | D7 — Data bus bit 7 |
| Chân 36 | D8 — Data bus bit 8 |
| Chân 37 | D9 — Data bus bit 9 |
| Chân 38 | D10 — Data bus bit 10 |
| Chân 39 | D11 — Data bus bit 11 |
| Chân 40 | D12 — Data bus bit 12 |
| Chân 41 | D13 — Data bus bit 13 |
| Chân 42 | D14 — Data bus bit 14 |
| Chân 43 | D15 — Data bus bit 15 |
| Chân 44 | GND — Ground |
| Chân 45 | BR — Bus Request |
| Chân 46 | BG — Bus Grant |
| Chân 47 | BGACK — Bus Grant Acknowledge |
| Chân 48 | RESET — Reset (active low) |
| Chân 49 | HALT — Halt (active low) |
| Chân 50 | CLK — System clock input |
| Chân 51 | VCC — +5V power supply |
| Chân 52 | TCLK — Timer clock |
| Chân 53 | TIN1 — Timer input 1 |
| Chân 54 | TOUT1 — Timer output 1 |
| Chân 55 | TIN2 — Timer input 2 |
| Chân 56 | TOUT2 — Timer output 2 |
| Chân 57 | IRQ1 — Interrupt request 1 |
| Chân 58 | IRQ2 — Interrupt request 2 |
| Chân 59 | IRQ3 — Interrupt request 3 |
| Chân 60 | IRQ4 — Interrupt request 4 |
| Chân 61 | IRQ5 — Interrupt request 5 |
| Chân 62 | IRQ6 — Interrupt request 6 |
| Chân 63 | GND — Ground |
| Chân 64 | CS0 — Chip select 0 |
| Chân 65 | CS1 — Chip select 1 |
| Chân 66 | CS2 — Chip select 2 |
| Chân 67 | CS3 — Chip select 3 |
| Chân 68 | RAS0 — DRAM row address strobe 0 |
| Chân 69 | RAS1 — DRAM row address strobe 1 |
| Chân 70 | CAS0 — DRAM column address strobe 0 |
| Chân 71 | CAS1 — DRAM column address strobe 1 |
| Chân 72 | VCC — +5V power supply |
| Chân 73 | WE — Write enable |
| Chân 74 | OE — Output enable |
| Chân 75 | TA — Transfer acknowledge |
| Chân 76 | R/W — Read/Write |
| Chân 77 | DS — Data strobe |
| Chân 78 | AS — Address strobe |
| Chân 79 | GND — Ground |
| Chân 80 | PA0 — Parallel I/O port A bit 0 |
| Chân 81 | PA1 — Parallel I/O port A bit 1 |
| Chân 82 | PA2 — Parallel I/O port A bit 2 |
| Chân 83 | PA3 — Parallel I/O port A bit 3 |
| Chân 84 | PA4 — Parallel I/O port A bit 4 |
| Chân 85 | PA5 — Parallel I/O port A bit 5 |
| Chân 86 | PA6 — Parallel I/O port A bit 6 |
| Chân 87 | PA7 — Parallel I/O port A bit 7 |
| Chân 88 | PB0 — Parallel I/O port B bit 0 |
| Chân 89 | PB1 — Parallel I/O port B bit 1 |
| Chân 90 | PB2 — Parallel I/O port B bit 2 |
| Chân 91 | PB3 — Parallel I/O port B bit 3 |
| Chân 92 | PB4 — Parallel I/O port B bit 4 |
| Chân 93 | PB5 — Parallel I/O port B bit 5 |
| Chân 94 | PB6 — Parallel I/O port B bit 6 |
| Chân 95 | PB7 — Parallel I/O port B bit 7 |
| Chân 96 | TXD1 — SCC1 transmit data |
| Chân 97 | RXD1 — SCC1 receive data |
| Chân 98 | TXD2 — SCC2 transmit data |
| Chân 99 | RXD2 — SCC2 receive data |
| Chân 100 | TXD3/RXD3 — SCC3 transmit/receive data |
Ứng dụng tiêu biểu
MC68LC302AF20VCT phù hợp cho 6 Áp dụngs: 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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho MC68LC302AF20VCT — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | 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) |
Bảo phân biệt quan trọng
- Lowest-cost variant of MC68302 in 100-LQFP footprint (vsMC68302AF20CT)
- Tray packaging (VCT) for low-volume and prototype builds (vsMC68LC302AF20CT)
- Same 100-LQFP AF footprint across LC and full feature families (vsMC68LC302PU20VCT)
Ghi chú thiết kế
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.
Thông tin tuân thủ
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.