CONEXANT CX24951

Broadband Modems
Cable Modems
Single-Chip Cable Modem Solution
DOCSIS 2.0-Based
™
CX24951
Conexant’s next generation cable modem solution
offers a DOCSIS 2.0-based single-chip modem while
providing dual software programmable network
processing engines
Conexant’s broadband communications portfolio includes a comprehensive
suite of semiconductor solutions that enable the digital home and information
network. The InfoSurge™ family of products, supporting broadband cable
modem applications, presents the industry with yet another example of
Conexant’s ability to exceed the needs of a growing market segment.
The CX24951, Conexant’s DOCSIS 2.0-based single-chip cable modem
solution, provides backwards compatibility with the DOCSIS 1.1 and the
DOCSIS 1.0 standards. The world’s fastest, lowest power and smallest cable
modem solution, the CX24951, offers 500 MIPS of processing power while
consuming just 550mW in a 17mm x 17mm BGA package.
The CX24951 fully supports the new upstream physical-layer modulation
technologies A-TDMA (Advanced Time Division Multiple Access) and S-CDMA
(Synchronous Code Division Multiple Access) as specified in DOCSIS 2.0
standard. These new modulation techniques significantly increase upstream
cable bandwidth for data transmissions (up to 30Mbps) without requiring
CX24951 Distinguishing Features
• A-TDMA and S-CDMA DOCSIS
2.0 upstream modulation
• High level of integration
(Single monolithic IC)
any physical rebuilding of cable networks.
• Dual software programmable
network processing engines
The CX24951’s 500 MIPS and software programmable dual processor architecture
• 500 MIPS of processing power
with on-chip memory for cable MAC and application layer processing makes
• Less than 550mW typical
power dissipation
it ideally suited for CableHome™ and PacketCable™ applications.
Dual Programmable Network Processors
The CX24951 utilizes the proven software programmable dual processor
architecture of its predecessor, the CX24943, and further boosts its
performance by increasing the instruction memory size to 128K bytes.
The CX24951 is pin compatible with the CX24943.
The dual network processing engine architecture offers real-time-critical
packet management processing and superior performance. The software
programmability of this architecture accommodates application specific
• Embedded IEEE 802.3 MAC with MII
• 12Mb USB 1.1 communications
transceiver
• Support for DOCSIS/EuroDOCSIS 2.0/
1.1/1.0, DVB and proprietary standards
• CableHome and PacketCable
compliant
• High density, 17mm x 17mm
BGA package
requirements, worldwide standards, and manufacturers’ unique value
added features for maximum flexibility.
Part Number CX24951
Description
Single-Chip Cable Modem
Broadband Modems
Cable Modems
The dual processor architecture of the CX24951 allows it to be
Highly Integrated
used in CableHome applications, without needing an additional
The CX24951 supports a number of interfaces including a USB 1.1
network processor for the firewall and routing features required
communications transceiver, an IEEE 802.3 10/100 Ethernet Media
by the CableHome standard. The firewall and routing algorithms
Access Controller (MAC) with a Media Independent Interface (MII)
required by CableHome take less than 10 percent of the 500 MIPS
for access to home networking standards. Examples are HPNA
processing power of the CX24951, leaving plenty of processing
2.0, HomePlug 1.0 and a host interface which supports seamless
power left for developing custom networking applications.
connectivity to any PCMCIA compliance device such as IEEE
802.11a and IEEE 802.11b wireless transceivers. The CX24951
The integrated MII port and the PCMCIA functionality of the
supports integrated and stand alone cable modems, home
integrated host port allow the CX24951 to provide a seamless
networking gateway products, IP (Internet Protocol) telephony
interface to an array of networking peripherals such as wireless
products, and digital set-top boxes.
LANs (802.11a/b), HomePlug transceivers, HPNA solutions, and
The CX24951 was developed using leading-edge process and
multi-port Ethernet Switches.
packaging technologies. This helps drive down the size of the
The CX24951 also supports PacketCable applications by
monolithic IC, package and power, while allowing clock rates
interfacing to Conexant’s voice DSP products to execute voice
to increase. The CX24951 dissipates less than 550mW of power
processing algorithms.
setting a new standard for the industry.
The CX24951, through its high level of integration, enables
manufacturers to develop a complete cable modem with a
minimal number of additional components as shown in the
CX24951-based cable modem block diagram.
LED Indicators
Cable
Tuner
GPIO
ADC
MII
DAC
Control
CX24951
4 MB
SDRAM
SDRAM
Interface
10/100
Ethernet
PHY
RJ-45
Conexant
HPNA 2.0
PHY
RJ-11
Conexant
HomePlug
PHY
Powerline
Type B
Socket
USB
Host
Interface
Conexant
Voice DSP
1.3v
Power
Supply
3.3v
5.0v
2 MB
Flash
802.11a/b
MAC/PHY
CX24951-based Cable Modem Block Diagram
RJ-11
RJ-11
Antenna
CX24951 Features
Increased Performance
Conexant’s seventh-generation physical-layer downstream
receiver includes a 10-bit A/D that accepts a direct IF signal
Flexible Platform
(at 44 or 36 MHz) and a QPSK/16/32/64/128/256 QAM
Cable modem manufacturers have to devote a significant
demodulator with Annex A, B and C forward error correction.
amount of resources to bring new certifiable solutions to
The CX24951 also contains an 11-bit D/A converter, which can
market. The unique architecture of the CX24951 provides a
accommodate 65 MHz of upstream bandwidth for EuroDOCSIS
number of advantages for cable modem manufacturers and
and DVB applications, and a QPSK/8/16/32/64/128 QAM burst
cable operators alike. The software programmability of the dual
upstream modulator. Conexant’s proven PHY technology exceeds
network processing engine allows manufacturers to customize
all DOCSIS/EuroDOCSIS 2.0/1.1/1.0 requirements for low BER
the CX24951 for application specific requirements, both at
in noise-filled environments.
the cable MAC and software applications layer.
The CX24951 is the fastest solution in the industry with
The software programmability of the CX24951 allows one base
integrated dual software programmable network processing
platform to support numerous products, including PacketCable,
engines on board. Its unique packet management, unified
CableHome and set-top box products as shown in the CX24951-
memory architecture, and advanced system buses, maximize
based cable modem block diagram. In addition, the architectural
performance by allowing segmentation of real-time-critical
similarities between the CX24951 and its predecessor, the
DOCSIS/EuroDOCSIS 2.0/1.1/1.0 functions from non
CX24943, allows for maximum reuse of certified code.
real-time-critical application processes. The CX24951
processor performance and unique architecture enables
DOCSIS/EuroDOCSIS 2.0/1.1/1.0 and other software applications,
including VPN firewall for added security and routing for
cable home or VoIP for PacketCable.
The CX24951 provides the ability to adapt to a multitude of
standards by downloading different software into the embedded
dual network processing engine, including DOCSIS/EuroDOCSIS
2.0/1.1/1.0, DVB and proprietary standards. Finally, cable operators
can download complex feature enhancements above and beyond
The CX24951 also incorporates a PHS (Payload Header
simple code upgrades to field-deployed solutions, minimizing truck
Suppression requirement introduced in DOCSIS 1.1) engine
rolls and equipment obsolescence.
in hardware. Implementation of PHS in hardware further boosts
the performance of the CX24951 by relieving the internal CPU
from performing repeated filtering operations.
Complete Hardware and Software Solution
To reduce the resources and development time required to bring
CX24951-based cable modem solutions to market, Conexant
provides complete certifiable DOCSlS/EuroDOCSIS 2.0/1.1/1.0
cable modem reference designs which incorporate all of the
hardware and software needed for DOCSIS certification.
DMA
Interrupt
Controllers
Applications
Network
Processor
Peripheral
I/O
Memory
Cable modem reference designs include Conexant software that
is compliant to DOCSIS/EuroDOCSIS 2.0/1.1/1.0 and include the
USB drivers that meet Microsoft’s Windows Hardware Quality Lab
(WHQL) requirements. Additional software enhancements that are
above and beyond standards-based requirements are also included
A
D
C
Cable PHY
Downstream
D
A
C
Cable PHY
Upstream
S-CDMA
A-TDMA
USB
Cable MAC
Network
Processor
Host
Interface
MII
CX24951 Single-Chip
Cable Modem IC Block Diagram
in this complete software offering.
Broadband Modems
Cable Modems
CX24951 Features
Cable PHY Downstream
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)
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
Cable PHY Upstream
•
•
•
•
•
USB 1.1
11-bit D/A
A-TDMA
S-CDMA with Turbo Trellis coding
QPSK/8/16/32/64/128 QAM burst modulator
Programmable pre-equalization
• Integrated 12 Mb transceiver
• Communications peripheral device
Memory
DMA Interrupt Controller
•
•
•
•
20 asynchronous channels
Memory to memory moves: aligned/unaligned
Source/destination mode for simple data transfer
Circular/linked buffer support for inbound/outbound data
Peripheral I/O
• 32 GPIO
• JTAG boundary scan
• UART
TDM clock and frame sync generator
Transmit clock generator
Supplied 25MHz Ethernet reference clock
Internal USB clock
Package and Power
•
•
•
•
• DOCSIS 2.0/1.1/1.0
• EuroDOCSIS 2.0/1.1/1.0
• PCI
Product Applications
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
(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)
MII
• IEEE 802.3 MAC layer
• Networking technologies
- 10/100 Ethernet
- Conexant HPNA 2.0
- Conexant HomePlug 1.0
© 2002, Conexant Systems, Inc. All Rights Reserved. Conexant and the Conexant
logo are registered trademarks of Conexant Systems, Inc. All other trademarks
are owned by their respective owners. Although Conexant strives for accuracy
in all its publications, this material may contain errors or omissions and is
THIS MATERIAL IS PROVIDED AS IS AND WITHOUT
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE AND NON-INFRINGEMENT.
www.conexant.com
General Information:
U.S. and Canada: (800) 854-8099
International: (949) 483-6996
Headquarters – Newport Beach
4311 Jamboree Rd, P.O. Box C
Newport Beach, CA 92660-3095
Conexant shall not be liable for any
special, indirect, incidental or consequential damages as a result of its use.
228 PBGA (17mm x 17mm)
All I/O at 3.3V
Power supply: 3.3V and 1.3V
<550 mW (typical)
Reference Designs
Application Network Processor
02-0671
•
•
•
•
• Watchdog timer
• Four additional timers
• Interrupt controller
• 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
subject to change without notice.
Phase-Locked Loops (4)
Miscellaneous Functions
Cable MAC Network Processor
•
•
•
•
•
• Internal 8K x 32 SRAM
• External SDRAM Interface
- 16-bit interface
- Supports both 4MB and 8MB technologies
Order# 102113A