23/04/2019
29 / 43
Version 1.09
2.9.4
LEDs
LED
Description
PWR
(D1202)
Power Good: Indicates that DC-DC converters are in regulation.
RDY
(D1201)
FPGA Ready: The RDY LED shows the configuration status of the FPGA. The LED is on
when a valid bitstream is loaded and off if no bitstream has been loaded or the FPGA
configuration has failed.
RX
(D401)
Can be configured to indicate receive activity of the USB 2.0 UART USB Device.
TX
(D402)
Can be configured to indicate transmit activity of the USB 2.0 UART USB Device.
FX3
(D301)
FX3 LED: Can be controlled by the user application running on the Cypress FX3 USB 3.0
controller.
Table 19: LEDs
2.9.5
I
2
C IO Expander
A Semtech SX1505 I
2
C IO Expander (U901) is used to read and control the following signals:
•
Set the state of the slave fifo address signal A0 and chip select signal SLCS#
•
Read the state of the PCIe reset signal PCIE_PERST#
•
Read the state of the FX3_USB_SEL signal (chooses device or host connector for the USB
signals coming from the FPGA module)
•
Read the state of the USB_CPEN signal (enables power to the USB 2.0 host connector)
•
Enable or disable the I
2
C bus on the HDMI or LPC FMC and extension connector respectively
by means of PCIE_I2C_EN and IO_I2C_EN signals.
•
Disable the write-protect signal of the user EEPROM
It uses the I
2
C address 0x21 (7 bit) and is connected to the I
2
C pins of the FPGA module and FX3.
For simple IO operations only the following two 8 bit registers are used. For more information about
the SX1505 please refer to the SX150x
3
datasheet.
Register Name
Description
0
Data
Read or write data
1
Direction
Direction (0=output, 1=input)
Table 20: I2C expander registers