Intel® Cyclone® 10 GX FPGA Development Kit User Guide

ID 683696
Date 8/15/2018
Document Table of Contents

4.9.3. SFP+ Interface

Two SFP+ connectors (J5, J6) are provided on the PCIe* bracket. Each connector supports a 10 GE SFP+ hot pluggable module.

Each SFP+ interface has the following signals:
  • Transceivers, x1 for each SFP+, up to 12.5 Gbps
  • SMBUS (I2C), 3.3V for SFP+ and I/O expander, level-translated 10 1.8V with U22/U23
  • IRQ of I/O expander, 3.3V level-translated to 1.8V with U19

Each SFP+ module has six status/control signals and two LEDs. The FPGA device does not have enough I/O pins for these signals, hence an I/O expander is used to implement these I/Os for each SFP+ connector. The I2C I/O expander is on the same I2C bus as the SFP+ module, and the I2C bus of two SFP+ modules are independent of each other.

The I/O expander used is TI TCA9534PWR. U20 is for SFP+ 0, with I2C address 7'b010_0000. U21 is for SFP+, with I2C address 7'b010_0000.

The I/O expander has 8 I/Os. The definition of the I/Os is shown in the table below. The device is controlled with I2C bus.

Table 16.  I/O Expander: I/O Definition
I/O Number Signal I/O Type Function
P0 SFP_RLED Output Red LED, indicates LOS/ERR, "0" - ON
P1 SFP_GLED Output Green LED, indicates Link, "0" - ON
P2 SFP_TXDIS Output Tx_Disable, Pulled up, Transmitter is turned off if high
P3 SFP_TFLT Input Tx_Fault, Pulled up, indicates fault when high
P4 SFP_RS1 Output Rate Select, Pulled up with 1K resistor
P5 SFP_RLOS Input Rx_LOS, Pulled up, indicates LOS when high
P6 SFP_RS0 Output Rate Select, Pulled up with 1K resistor
P7 SFP_PRSN Input Mod_ABS, Pulled up, module in place when low

The I/Os of TCA9534 is in high impedance input mode upon power up. Hence, the module is placed in TX_Disable mode and the LEDs are off. The status changes on the I/Os are reported with an IRQ to the FPGA. Each I/O expander has its own dedicated IRQ signal.

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