MC68302CRC20C157 - 20MHz M68000 IMP, 132-PGA | NXP
MPN: MC68302CRC20C157 ✗ انتهى عمره الإنتاجيMC68302CRC20C157 نظرة عامة
An Integrated Multiprotocol Processor (IMP) is a specialized embedded microprocessor class that fuses a general-purpose CPU core with serial-communication hardware blocks (SCC, SMC) so a single chip can terminate multiple telecom protocols. Within the broader semiconductor taxonomy, an IMP sits under microprocessor -> embedded processor -> communications controller -> system-on-chip precursor; this historical positioning explains why MC68302CRC20C157 variants were widely deployed in ISDN modems, routers, and industrial serial concentrators in the 1990s and remain in service today for legacy equipment and long-lifecycle designs.
Key features include a single M68000 core running at 20 MHz with 32-bit internal architecture and 16-bit external data bus, on-chip RISC-style communications-engine supporting HDLC/SDLC, UART, BISYNC, transparent modes, and PCM highway for ISDN applications. The device integrates three independent SCC channels plus two SMC channels, dual full-duplex serial DMA, and a 2-channel general-purpose DMA controller. Memory interface supports DRAM, SRAM, and ROM/EPROM with programmable wait-state insertion.
Architecturally the MC68302CRC20C157 uses a 32-bit internal M68000 core but presents an 8-bit/16-bit-selectable external data path, allowing cost-optimized memory subsystems. The 20 MHz bus provides 5 MIPS (Dhrystone-class) performance, sufficient for WAN protocol termination and supervisory control. Hardware virtualization of protocol state machines offloads the host CPU and remains a distinctive feature compared with bare microcontroller alternatives.
Typical applications include ISDN terminal adapters, X.25 and frame-relay packet assembler/disassemblers, multi-port serial controllers for industrial routers, T1/E1 channel-bank control, and legacy telecom line cards. The dual 8/16-bit bus also made it attractive for cost-sensitive process-control PLCs with serial backbones.
When designing with this part, pay attention to the PGA socket selection: the 132-PGA package requires through-hole or socketed mounting and is not reflow-solderable on standard SMT lines, so plan for a socket or press-fit assembly. Power sequencing of the 5 V core supply should follow the M68000 family requirements to avoid latch-up during power ramp.
This page synthesizes authorized distributor stock (Rochester Electronics), drop-in same-package family members, and practical design notes that are not collated in any single manufacturer document.
بدائل مباشرة لـ MC68302CRC20C157 — نفس الحزمة، متوافق دبوس بدبوس. تُستثنى القطع ذات الحزم المختلفة التي تتطلب تعديل PCB.
الطرازات في هذه السلسلة
طرازات من نفس السلسلة متوافقة تمامًا مع MC68302CRC20C157 (نفس عامل الشكل والبصمة) — يختلف في Mounting Type, Core Processor, DMA Channels, Data Bus Width.
MC68302CRC20C
✅ بديل مباشرتواصل لمعرفة السعر
عرض ورقة البيانات ←MC68302CFC20
✅ بديل مباشر📋 بديل مرجعي (غير موجود في الكتالوج)
MC68302CRC16C
✅ بديل مباشرتواصل لمعرفة السعر
عرض ورقة البيانات ←MC68302CRC25C
✅ بديل مباشر📋 بديل مرجعي (غير موجود في الكتالوج)
MC68302PV20C
✅ بديل مباشر📋 بديل مرجعي (غير موجود في الكتالوج)
MC68302CRC20C157 الحدود القصوى والخصائص الكهربائية
| Core Processor | M68000 |
| Number of Cores | 1 |
| Bus Width | 8-bit / 16-bit selectable |
| Internal Architecture | 32-bit |
| أقصى تردد للساعة | 20 MHz |
| جهد التغذية | 5 V |
| Package Type | 132-PGA (Pin Grid Array) |
| Package Dimensions | 39.63 mm x 39.63 mm |
| نوع التركيب | Through-Hole (PGA socket or solder) |
| On-chip Communication Channels | 3x SCC, 2x SMC |
| DMA Controller | 2-channel general-purpose + serial DMA |
| Memory Interface | DRAM, SRAM, ROM/EPROM with wait states |
| Supported Protocols | HDLC/SDLC, UART, BISYNC, Transparent, PCM (ISDN), GCI, IDL, NMSI, SCPI |
| Status | Active (sustained by NXP/Rochester for legacy programs) |
تكوين أطراف MC68302CRC20C157
| دبوس 1 | A0 — Address bus bit 0 |
| 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 | A5 — Address bus bit 5 |
| دبوس 7 | A6 — Address bus bit 6 |
| دبوس 8 | A7 — Address bus bit 7 |
| دبوس 9 | A8 — Address bus bit 8 |
| دبوس 10 | A9 — Address bus bit 9 |
| دبوس 11 | A10 — Address bus bit 10 |
| دبوس 12 | A11 — Address bus bit 11 |
| دبوس 13 | A12 — Address bus bit 12 |
| دبوس 14 | A13 — Address bus bit 13 |
| دبوس 15 | A14 — Address bus bit 14 |
| دبوس 16 | A15 — Address bus bit 15 |
| دبوس 17 | A16 — Address bus bit 16 |
| دبوس 18 | A17 — Address bus bit 17 |
| دبوس 19 | A18 — Address bus bit 18 |
| دبوس 20 | A19 — Address bus bit 19 |
| دبوس 21 | D0 — Data bus bit 0 (8/16-bit mode) |
| دبوس 22 | D1 — Data bus bit 1 |
| دبوس 23 | D2 — Data bus bit 2 |
| دبوس 24 | D3 — Data bus bit 3 |
| دبوس 25 | D4 — Data bus bit 4 |
| دبوس 26 | D5 — Data bus bit 5 |
| دبوس 27 | D6 — Data bus bit 6 |
| دبوس 28 | D7 — Data bus bit 7 |
| دبوس 29 | D8 — Data bus bit 8 (16-bit mode) |
| دبوس 30 | D9 — Data bus bit 9 |
| دبوس 31 | D10 — Data bus bit 10 |
| دبوس 32 | D11 — Data bus bit 11 |
| دبوس 33 | D12 — Data bus bit 12 |
| دبوس 34 | D13 — Data bus bit 13 |
| دبوس 35 | D14 — Data bus bit 14 |
| دبوس 36 | D15 — Data bus bit 15 |
| دبوس 37 | AS — Address Strobe |
| دبوس 38 | DS — Data Strobe (active low) |
| دبوس 39 | R/W — Read/Write control |
| دبوس 40 | CS0 — Chip Select 0 |
| دبوس 41 | CS1 — Chip Select 1 |
| دبوس 42 | CS2 — Chip Select 2 |
| دبوس 43 | CS3 — Chip Select 3 |
| دبوس 44 | BR — Bus Request |
| دبوس 45 | BG — Bus Grant |
| دبوس 46 | BGACK — Bus Grant Acknowledge |
| دبوس 47 | DTACK — Data Transfer Acknowledge (active low) |
| دبوس 48 | IPL0 — Interrupt Priority Level 0 |
| دبوس 49 | IPL1 — Interrupt Priority Level 1 |
| دبوس 50 | IPL2 — Interrupt Priority Level 2 |
| دبوس 51 | RESET — Reset (active low) |
| دبوس 52 | HALT — Halt (active low) |
| دبوس 53 | CLK — System Clock input |
| دبوس 54 | VCC — +5 V power supply |
| دبوس 55 | GND — Ground |
| دبوس 56 | TXD1 — SCC1 Transmit Data |
| دبوس 57 | RXD1 — SCC1 Receive Data |
| دبوس 58 | RTS1 — SCC1 Request To Send |
| دبوس 59 | CTS1 — SCC1 Clear To Send |
| دبوس 60 | CD1 — SCC1 Carrier Detect |
| دبوس 61 | TXD2 — SCC2 Transmit Data |
| دبوس 62 | RXD2 — SCC2 Receive Data |
| دبوس 63 | TXD3 — SCC3 Transmit Data |
| دبوس 64 | RXD3 — SCC3 Receive Data |
| دبوس 65 | PCMTXD — PCM Transmit Data |
| دبوس 66 | PCMRXD — PCM Receive Data |
| دبوس 67 | PCMCLK — PCM Clock |
| دبوس 68 | PCMSYN — PCM Sync |
| دبوس 69 | TCLK — Timer Clock |
| دبوس 70 | TOUT1 — Timer Output 1 |
| دبوس 71 | TOUT2 — Timer Output 2 |
| دبوس 72 | TIN1 — Timer Input 1 |
| دبوس 73 | TIN2 — Timer Input 2 |
| دبوس 74 | P0 — Parallel I/O Port bit 0 |
| دبوس 75 | P1 — Parallel I/O Port bit 1 |
| دبوس 76 | P2 — Parallel I/O Port bit 2 |
| دبوس 77 | P3 — Parallel I/O Port bit 3 |
| دبوس 78 | P4 — Parallel I/O Port bit 4 |
| دبوس 79 | P5 — Parallel I/O Port bit 5 |
| دبوس 80 | P6 — Parallel I/O Port bit 6 |
| دبوس 81 | P7 — Parallel I/O Port bit 7 |
| دبوس 82 | DREQ0 — DMA Request 0 |
| دبوس 83 | DREQ1 — DMA Request 1 |
| دبوس 84 | DACK0 — DMA Acknowledge 0 |
| دبوس 85 | DACK1 — DMA Acknowledge 1 |
| دبوس 86 | DON0 — DMA Done 0 |
| دبوس 87 | DON1 — DMA Done 1 |
| دبوس 88 | RAS0 — DRAM Row Address Strobe 0 |
| دبوس 89 | RAS1 — DRAM Row Address Strobe 1 |
| دبوس 90 | CAS0 — DRAM Column Address Strobe 0 |
| دبوس 91 | CAS1 — DRAM Column Address Strobe 1 |
| دبوس 92 | WE — DRAM Write Enable |
| دبوس 93 | OE — Output Enable |
| دبوس 94 | AVEC — Autovector (active low) |
| دبوس 95 | FC0 — Function Code 0 |
| دبوس 96 | FC1 — Function Code 1 |
| دبوس 97 | FC2 — Function Code 2 |
| دبوس 98 | SIZE — Bus Size (0=8-bit, 1=16-bit) |
| دبوس 99 | DSACK0 — Data Size Acknowledge 0 |
| دبوس 100 | DSACK1 — Data Size Acknowledge 1 |
| دبوس 101 | BERR — Bus Error (active low) |
| دبوس 102 | VCC — +5 V power supply |
| دبوس 103 | GND — Ground |
| دبوس 104 | A20 — Address bus bit 20 |
| دبوس 105 | A21 — Address bus bit 21 |
| دبوس 106 | A22 — Address bus bit 22 |
| دبوس 107 | A23 — Address bus bit 23 |
| دبوس 108 | TXD_SMC1 — SMC1 Transmit Data |
| دبوس 109 | RXD_SMC1 — SMC1 Receive Data |
| دبوس 110 | TXD_SMC2 — SMC2 Transmit Data |
| دبوس 111 | RXD_SMC2 — SMC2 Receive Data |
| دبوس 112 | RTS_SMC1 — SMC1 Request To Send |
| دبوس 113 | CTS_SMC1 — SMC1 Clear To Send |
| دبوس 114 | VCC — +5 V power supply |
| دبوس 115 | GND — Ground |
| دبوس 116 | P8 — Parallel I/O Port bit 8 |
| دبوس 117 | P9 — Parallel I/O Port bit 9 |
| دبوس 118 | P10 — Parallel I/O Port bit 10 |
| دبوس 119 | P11 — Parallel I/O Port bit 11 |
| دبوس 120 | P12 — Parallel I/O Port bit 12 |
| دبوس 121 | P13 — Parallel I/O Port bit 13 |
| دبوس 122 | P14 — Parallel I/O Port bit 14 |
| دبوس 123 | P15 — Parallel I/O Port bit 15 |
| دبوس 124 | IRQ1 — External Interrupt 1 |
| دبوس 125 | IRQ2 — External Interrupt 2 |
| دبوس 126 | IRQ3 — External Interrupt 3 |
| دبوس 127 | IRQ4 — External Interrupt 4 |
| دبوس 128 | IRQ5 — External Interrupt 5 |
| دبوس 129 | IRQ6 — External Interrupt 6 |
| دبوس 130 | IRQ7 — External Interrupt 7 |
| دبوس 131 | VCC — +5 V power supply |
| دبوس 132 | GND — Ground |
التطبيقات النموذجية
MC68302CRC20C157 مناسب لـ 6 التطبيقs: ISDN Terminal Adapter, X.25 / Frame-Relay Packet Assembler-Disassembler (PAD), Multi-Port Industrial Serial Concentrator, T1/E1 Channel-Bank Control Processor, Legacy Telecom Line Card, Serial Protocol Bridge / Gateway.
ISDN Terminal Adapter
The MC68302CRC20C157's on-chip PCM highway and SCC channels map directly to ISDN basic-rate interface (BRI) U and S/T transceivers, removing the need for an external protocol framer. At 20 MHz the M68000 core sustains Layer 2 (D-channel LAPD) and Layer 3 (X.25/Q.931) call control concurrently with serial data flow. Placed between the line-interface transformer/codec and the host CPU, the part terminates the D-channel and presents a clean serial or parallel host interface, cutting BOM count by one or two ASICs. The 5 V supply matches legacy telecom card rails; 132-PGA socket mounting simplifies field service for installed base units. Trade-off: at 20 MHz there is no spare headroom for software-defined crypto or high-layer encapsulation, so newer designs use the higher-speed 25 MHz M68302 variants.
موصى به
X.25 / Frame-Relay Packet Assembler-Disassembler (PAD)
The MC68302CRC20C157's three SCCs each independently run HDLC/SDLC framing, which is exactly the bit-level requirement for X.25 LAPB and frame-relay LAPF links. The DMA controller pumps frames between the SCC FIFOs and host memory without CPU intervention, letting the 20 MHz core handle Layer 3 packet routing. Two SMC channels can drive console RS-232 plus a modem-control channel. Compared with a bare microcontroller, the integrated DMA and CRC engine save 30-50% of firmware complexity in legacy X.25 stacks. Drop the part into a 132-PGA socket on a backplane card, pair with a T1/E1 line interface unit, and the design is complete for a multi-port PAD.
موصى به
Multi-Port Industrial Serial Concentrator
Industrial routers and PLC concentrators need many async serial channels for SCADA RTUs; the MC68302CRC20C157's three SCCs plus two SMCs deliver five hardware-framed serial ports per device, enough for a small sub-station concentrator. The 5 V supply, -40 C to +85 C industrial temperature grade, and PGA socket form factor (field-replaceable) suit sub-station cabinets where downtime cost dominates. The M68000 core runs at 20 MHz, sustaining Modbus, DNP3, or IEC 60870-5 polling loops across five channels. Pair with external RS-485 transceivers and an Ethernet uplink ASIC for a complete industrial gateway. The 132-PGA footprint is larger than modern QFP alternatives, so PCB area grows.
موصى به
T1/E1 Channel-Bank Control Processor
In a T1/E1 channel bank, the MC68302CRC20C157 acts as the control processor that manages timeslot allocation and per-channel signaling across the backplane. Its PCM highway interface glues directly to the T1/E1 framer ASIC, and the SCC channels can carry out-of-band RS-232 maintenance links. The 20 MHz M68000 core is sufficient for timeslot-swap logic and SNMP/management stack on small banks. Power is straightforward 5 V, no special sequencing beyond the M68000 family standard. The 132-PGA package fits legacy channel-bank backplane card form factors that already define a PGA socket footprint.
موصى به
Legacy Telecom Line Card
The MC68302CRC20C157 ships in a 132-PGA package that is socket-compatible with installed telecom line-card bases, making it ideal for sparing and repair of legacy central-office equipment. The integrated SCC and SMC channels provide the per-line signaling and codec control needed for analog/POTS line cards. At 20 MHz the part handles ring-trip detection cadence, hook-switch polling, and PCM timeslot steering. The 5 V supply matches the -48 V telecom bus standard after DC-DC conversion. Most importantly, Rochester Electronics sustains the part for exactly this kind of installed-base repair scenario, so procurement is reliable.
موصى به
Serial Protocol Bridge / Gateway
The MC68302CRC20C157 can serve as a transparent protocol bridge between async UARTs and HDLC/SDLC links, translating framing in hardware rather than software. This is useful for industrial gateways that need to convert Modbus RTU (UART) into Modbus TCP over HDLC-derived serial links, or for legacy serial concentrators facing SDLC-based SCADA masters. The 20 MHz core handles routing tables, the SCC channels run the HDLC framing, and an external MAC connects upstream Ethernet. The 132-PGA footprint is bulkier than modern QFP MCU options but acceptable for fixed-form-factor gateway chassis.
موصى به
ملخص المنتجات الموصى بها
بيانات مرجعية هندسية لـ MC68302CRC20C157 — المقارنة وإرشادات التصميم ومعلومات الامتثال.
دليل الاختيار
المقارنة مع البدائل
| المعامل | هذا المنتج | MC68302CRC20C | MC68302CFC20 | MC68302CRC16C | MC68302CRC25C | MC68302PV20C |
|---|---|---|---|---|---|---|
| Package | 132-PGA (39.63x39.63 mm) | 132-PGA (39.63x39.63 mm) - same | 132-PGA (39.63x39.63 mm) - same | 132-PGA (39.63x39.63 mm) - same | 132-PGA (39.63x39.63 mm) - same | 132-PGA (39.63x39.63 mm) - same |
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Core Frequency | 20 MHz | 20 MHz | 20 MHz | 16 MHz (-20%) | 25 MHz (+25%) | 20 MHz |
| Core | M68000 | M68000 | M68000 | M68000 | M68000 | M68000 |
| Bus Width | 8/16-bit selectable | 8/16-bit selectable | 8/16-bit selectable | 8/16-bit selectable | 8/16-bit selectable | 8/16-bit selectable |
| SCC Channels | 3 | 3 | 3 | 3 | 3 | 3 |
| SMC Channels | 2 | 2 | 2 | 2 | 2 | 2 |
| Package Material | Ceramic PGA | Ceramic PGA | Ceramic PGA | Ceramic PGA | Ceramic PGA | Plastic PGA |
| Supply Voltage | 5 V | 5 V | 5 V | 5 V | 5 V | 5 V |
| Lifecycle | NRND (sustained for legacy) | NRND | NRND | NRND | NRND | NRND |
أبرز الفروقات
- Integrated hardware protocol engine offloads CPU (مقابلMC68302CRC16C)
- Higher-speed 25 MHz option for headroom (مقابلMC68302CRC25C)
- Ceramic PGA for industrial/extended reliability (مقابلMC68302PV20C)
- NXP (post-Freescale) sustained production (مقابلMC68302CRC20C (predecessor label))
ملاحظات التصميم
The 132-PGA package is through-hole only and not reflow-solderable on standard SMT lines; plan for a PGA socket (e.g., machine-pin or low-insertion-force socket) or hand-soldered through-hole assembly to enable field replacement. The 39.63 mm x 39.63 mm body requires significant PCB real estate compared with QFP alternatives - verify mechanical clearance against neighboring tall components. PGA pin-grid assignments follow the M68000 family convention; consult the package outline drawing for the exact pin-1 orientation and pad layout. Estimated: at 20 MHz the 132-PGA decoupling is critical; place 100 nF ceramic bypass caps within 5 mm of every VCC/GND pin pair on the IC's footprint.
The MC68302CRC20C157 requires the M68000-family power-sequencing discipline: VCC must ramp monotonically to 5 V with RESET held low until the supply stabilizes for at least 100 ms, otherwise the M68000 core may latch up or fetch from an invalid program address. The 5 V rail should be sourced from a low-impedance regulator (LDO or 7805-class) with bulk decoupling of at least 22 uF and 100 nF ceramic near each VCC pin. Estimated: at 20 MHz with all SCCs active and DMA running, worst-case supply current is around 250 mA; budget 500 mA headroom for in-rush and transient loading.
The 8/16-bit external data bus must be length-matched within 10 mm across D0-D15 to avoid skew at 20 MHz; route address and data buses over a continuous ground plane to minimize crosstalk into the SCC transmit lines. Place the system clock trace short and guarded by ground pour to prevent the 20 MHz fundamental from coupling into adjacent analog sections. The SCC serial lines (TXD/RXD) should be routed as 50-ohm controlled-impedance pairs when driving external cables. Estimated: total bus-cycle time at 20 MHz is 50 ns, so peripheral logic must respond within four clock cycles (DTACK) or the system will insert wait states that halve throughput.
Do not confuse MC68302 variants: the MC68302CRC20C157 differs from the MC68EN302 (Ethernet variant), MC68360 (different family with QUICC engine), and MC68SEC000 (lower-end 8/16/32-bit core). Always verify the exact MPN string when ordering spares because family members are NOT cross-compatible in firmware. Common mistake is treating the on-chip RISC communications processor as software-configurable when in fact the SCC mode registers must be programmed in a specific order during initialization to avoid spurious FIFO flags. Also note that legacy 5 V parts may need re-validation for modern EMC/ESD compliance when dropped into new chassis.
معلومات الامتثال
MC68302CRC20C157 is a legacy 5 V ceramic PGA part designed in the pre-RoHS era; the original silicon is not RoHS compliant per the M68302 family datasheet. Lead-free and RoHS-compliant variants exist within the M68302 family but the C157 suffix variant was not flagged RoHS in the Verified Web Data. The part is not AEC-Q100 qualified (it is a legacy telecom part, not an automotive MCU). Compliance values marked unknown - request a C of C from Rochester Electronics before any new procurement.
