Broadband Modems
Cable Modems
CX24951 Features
Cable PHY Downstream
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10-bit A/D
Direct IF sampling at 44 and 36 MHz
QPSK/16/32/64/128/256 QAM demodulator
Programmable equalization
Annex A, B and C FEC
11-bit D/A
A-TDMA
S-CDMA with Turbo Trellis coding
QPSK/8/16/32/64/128 QAM burst modulator
Programmable pre-equalization
20 asynchronous channels
Memory to memory moves: aligned/unaligned
Source/destination mode for simple data transfer
Circular/linked buffer support for inbound/outbound data
Host Interface
• Master mode
- 16-bit data
- 8-chip selects
• Supports Flash, IP telephony, PCMCIA
- IEEE 802.11a or IEEE 802.11b
- 16/32-bit Slave mode (external host and test)
Cable PHY Upstream
USB 1.1
• Integrated 12 Mb transceiver
• Communications peripheral device
Memory
• Internal 8K x 32 SRAM
• External SDRAM Interface
- 16-bit interface
- Supports both 4MB and 8MB technologies
DMA Interrupt Controller
Phase-Locked Loops (4)
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TDM clock and frame sync generator
Transmit clock generator
Supplied 25MHz Ethernet reference clock
Internal USB clock
Peripheral I/O
• 32 GPIO
• JTAG boundary scan
• UART
Miscellaneous Functions
• Watchdog timer
• Four additional timers
• Interrupt controller
Cable MAC Network Processor
• Software Programmable
- DOCSIS 2.0/1.1/1.0 compliant
- EuroDOCSIS 2.0/1.1/1.0 compliant
- DVB compliant
- Fixed wireless compliant
- Proprietary standards
• Two PHS engines
• Internal 64KB data memory
• Internal 128KB Instruction memory
• Three 56-bit DES/CRC engines
• PID, SID, DA/SA, MAC, IP and LLC filtering
Package and Power
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228 PBGA (17mm x 17mm)
All I/O at 3.3V
Power supply: 3.3V and 1.3V
<550 mW (typical)
Reference Designs
• DOCSIS 2.0/1.1/1.0
• EuroDOCSIS 2.0/1.1/1.0
• PCI
Application Network Processor
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ARM940T microcontroller
Up to 225 MHz operation
4KB instruction and 4KB data cache
Embedded ICE and debug extensions
HCS 16- and 32-bit CRC single-cycle engines
Product Applications
MII
• IEEE 802.3 MAC layer
• Networking technologies
- 10/100 Ethernet
- Conexant HPNA 2.0
- Conexant HomePlug 1.0
(DOCSIS/EuroDOCSIS 2.0/1.1/1.0, DVB, Proprietary)
• Cable Modems with Ethernet
• Cable Modems with USB
• Cable Modems with IP Telephony
• PCI Cable Modem Card Internal (CMCI)
• Cable Modem with Home Networking
• PCMCIA Cable Modem
• Digital Set-Top Box with Cable Modem
• CPE Controlled Cable Modem (CCCM)
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are owned by their respective owners. Although Conexant strives for accuracy
in all its publications, this material may contain errors or omissions and is
subject to change without notice.
THIS MATERIAL IS PROVIDED AS IS AND WITHOUT
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE AND NON-INFRINGEMENT.
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