Spartan-3A DSP 3400A Edition User Guide
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31
UG498 (v2.2) November 17, 2008
Spartan-3A DSP 3400A Edition Board Hardware
R
20.
Clock Generator
IDT IDT5V9885PFGI. Used to generate different clocks on the Spartan-3A DSP 3400A
Edition board.
Table 1-14
summarizes the default settings of output clocks. The clock
generator can be programmed through the I
2
C interface (see
“I2C Bus Addressing,”
page 42
) or through a JTAG interface using connector P2 (see
Chapter 3,
“Programming the IDT Clock Chip”
for information).
21.
64-Kb I
2
C EEPROM
The I
2
C EEPROM 24LC64 can be used to store non-volatile data, for example, an
Ethernet MAC address. The EEPROM is accessible through the I
2
C bus (see
“I2C Bus
Addressing”
). The EEPROM write-protect is disabled on the board. I
2
C bus pull-up
resistors are provided on the board.
The I
2
C bus is extended to the FMC expansion connector so that the board can access
additional I
2
C devices and share the I
2
C controller in the FPGA.
22.
I
2
C Fan Controller and Temperature/voltage Monitor
Onboard temperature and voltage monitoring and control are handled by an Analog
Devices ADT7476A device. This device is controlled through I
2
C (
“I2C Bus
Addressing”
) and do the following:
♦
Measure the voltage of the 5-V, 3.3-V, 1.8-V, and 1.0-V supplies
♦
Measure the FPGA temperature through the DXP/DXN pins on the FPGA
♦
Measure ambient temperature
♦
Read power good status signals from the 2.5-V linear regulators
Table 1-14:
Clock Generator Default Settings
Clock
Generator
Output
FPGA Pin (if
Connected to
FPGA)
Default
Frequency
Clock Usage
1
NA
25 MHz
Ethernet PHY clock
2
NA
14.31818 MHz
Audio codec clock
3
NA
12 MHz
USB clock
4_P
NA
31.25 MHz
System ACE clock
4_N
AE13
31.25 MHz
FPGA clock
5_P
AA13
125 MHz
FPGA LVDS differential clock P
5_N
Y13
125 MHz
FPGA LVDS differential clock N
6
AF13
27 MHz
FPGA clock
Table 1-15:
I
2
C FPGA Pin Assignments
I
2
C Signal
FPGA Pin
Description
IIC_SCLK
AF23
(1)
1. I
2
C bus connected to FPGA through I
2
C MUX (U1). MUX needs
to be configured for the proper channel.
I
2
C clock
IIC_SDAT
AE25
(1)
I
2
C data
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