82562EZ(EX)/82547GI(EI) Dual Footprint Design Guide
2.2
CSA Port Connection to 82547GI(EI) Gigabit Ethernet
Controller
The 82547GI(EI) Gigabit Ethernet Controller uses the Communications Streaming Architecture
(CSA) port to connect to the Memory Control Hub (MCH). CSA is a point-to-point interface
supporting one device.
CSA has a theoretical bandwidth of 266 MB/s, sufficient to support Gigabit Ethernet speeds. The
connection to the MCH places the Ethernet controller close to system memory for minimum
latency.
The CSA interface uses IGTL buffers to achieve very high data speeds while controlling
transmission line characteristics. For details on connecting the CSA interface between the
82547GI(EI) Gigabit Ethernet Controller and the MCH, please refer to the Intel
®
865 Chipset
design guide, or the Intel
®
875 Chipset design guide.
2.2.1
Generation/Distribution of Reference Voltages
The 11-bit CSA port on the 82547GI(EI) controller has a dedicated CI_VREF pin to sample the
reference voltage. The nominal CSA port reference voltage is 0.35 V ± 3%. In addition to the
reference voltage, a reference swing voltage, CI_SWING must be supplied to control buffer
voltage swing characteristics. The nominal CSA port reference voltage swing must be 0.8 V
±
3%.
Table 3.
CSA Port Reference Circuit Specifications
Reference Voltage
Specification (V)
0.350 ± 3%
Reference Swing Voltage
Specification (V)
0.8 ± 3%
1.2 V Voltage Divider Circuit
Recommended Resistor Values (Ω)
R1 = 523 ± 1%
R2 = 665 ± 1%
R3 = 604 ± 1%
1.2V
0.8 V
R3
CI_SWING
C1
R2
C2
Intel®
82547GI(EI)
CI_VREF
C1
R1
C2
0.35 V
Figure 2. CSA Port Locally Generated Reference Divider Circuits
4
INTEL [ INTEL CORPORATION ]
