Xilinx ML310 - Manual (Page 49)

ML310 User Guide www.xilinx.com 49
UG068 (v1.01) August 25, 2004 1-800-255-7778
Board Hardware R
review the GD82559 Data sheet, located on the ML310 CDROM, for more detailed
information.
IIC/SMBus Interface
Introduction to IIC/SMBus
The Inter Integrated Circuit (IIC) bus provides the connection from the CPU to peripherals.
It is a serial bus with a data signal, SDA, and a clock signal, SCL, both of which are
bidirectional. The interface is designed to serve as an interface with multiple different
devices, with one master device and multiple slave devices. The interface is designed to
operate in the range of 100 KHz to 400 KHz.
The Systems Management Bus (SMBus) also provides connectivity from the CPU to
peripherals. The SMBus is also a two wire serial bus through which simple power related
devices can communicate with the rest of the system. SMBus uses IIC as its backbone.The
EDK kit provides IP that integrates the IIC interface with a microprocessor system, please
review the EDK Processor IP reference Guide for more details.
IIC/SMBus Signaling
There are two main signals on the IIC Bus, the data signal and the clock signal. Both of
these signals operate as open-drain, by default pulled high to 5 Volts, although some
devices support lower voltages. Either the master device or a slave device can drive either
of the signals low to transmit data or clock signals.
IIC/SMBus on ML310 Board
Table 2-22 provides a listing of the function, part number and addresses of the IIC devices
on the ML310. These devices include EEPROM, temperature sensors, power monitors and
Real Time Clock.
Figure 2-13: Intel GD82559 Ethernet Controller
PCI_P_AD23
Vendor ID 0x8086
Device ID 0x1229
PCI_BUS
IDSEL
INTEL
GD82559
Ethernet MAC/PHY
OSC
25MHz
X5
EEPROM
U16
RJ45
J3
FPGA
XC2VP30
PCI_BUS
PCI_P_CLK2
U37
U11