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Chapter 1: ML405 Evaluation Platform
14. IIC Bus with 4 Kb EEPROM
An IIC EEPROM (Microchip Technology 24LC04B-I/ST) is provided on the ML405 board
to store non-volatile data such as an Ethernet MAC address. The EEPROM write protect is
disabled on the ML405 board. The IIC bus uses 2.5V signaling and can operate at up to 400
kHz. IIC bus pull-up resistors are provided on the board.
The IIC bus is extended to the expansion connector so that the user can add additional IIC
devices and share the IIC controller in the FPGA. If the expansion IIC bus is used, the user
must have additional IIC pull-up resistors present on the expansion card. Bidirectional
level shifting transistors allow the expansion card to use 2.5V to 5V signaling on the IIC
bus.
A dual 1-of-4 FET multiplexer/demultiplexer chip (U60) allows the FPGA to
independently access multiple IIC buses without concern for IIC device address overlap.
See
Table 1-12: IIC Mux Options
Notes:
1. Pull-down resistors default the IIC Mux to this connection
15. VGA Output
A VGA output port (P2) is present on the board to support an external video monitor. On
ML405, the VGA circuitry utilizes a 330-MHz, 15-bit color video DAC (Analog Devices
ADV7125JST330). The FPGA can drive only five bits of data per color (red, green, and
blue).
The VGA connector supports the IIC protocol to allow the board to read the monitor's
configuration parameters (for example, plug and play support. See
EEPROM"
16. PS/2 Mouse and Keyboard Ports
The ML405 evaluation platform contains two PS/2 ports: one for a mouse (J17) and the
other for a keyboard (J18). Bidirectional level shifting transistors allow the FPGA's
2.5V I/O to interface with the 5V I/O of the PS/2 ports. The PS/2 ports on the board are
powered directly by the main 5V power jack; this jack also powers the rest of the board.
22
Table 1-12
for summary of IIC Mux options.
IIC Bus Connection
IIC EEPROM and expansion connector
SFP Module
VGA Connector (to read monitor configuration
parameters, for example: plug-and-play support)
USB Controller's IIC EEPROM
for more information.
Caution!
The power load of any attached PS/2 device must not overload the AC
adapter.
www.xilinx.com
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"14. IIC Bus with 4 Kb
ML405 Evaluation Platform
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