ZHCSUH8B December 2017 – January 2024 FPC202
PRODUCTION DATA
The FPC202 has four general-purpose outputs per port which can be used to drive the low-speed inputs to the module. The host controller can change the state of these outputs for each port individually, for all ports connected to a given FPC202 device simultaneously, or for all ports in the system simultaneously.
There are two configuration registers for these outputs. One register configures the enable state of the S0_OUT_A, S0_OUT_B, S1_OUT_A, and S1_OUT_B pins for every port, and by default the S0_OUT_A, S0_OUT_B, S1_OUT_A, and S1_OUT_B pins are disabled (tri-stated). The second register controls the output value for all S0_OUT_A, S0_OUT_B, S1_OUT_A, and S1_OUT_B pins, where S0_OUT_A/S1_OUT_A have default values of '1' and S0_OUT_B/S1_OUT_B have default values of '0'. The output values should be configured before the outputs are enabled. If a default value is desired during boot-up before these pins are enabled, a 10-kΩ pull-up or pull-down resistor is recommended (note that SFP and QSFP modules have internal pull-up and pull-downs on certain inputs). Note that if the VDD1 rail does not have power and there is an externally powered pull-up resistor connected to an output pin, the output pin will be pulled low until VDD1 is supplied.
An example signal connection is provided below. S0_OUT_A, S0_OUT_B, S1_OUT_A, and S1_OUT_B are not restricted to this port pin assignment, and they can be used to drive any 3.3-V signal required for the application, provided the IOH and IOL limits are met.
PIN NAME | EXAMPLE CONNECTION | COMMENT | |
---|---|---|---|
SFP | QSFP | ||
S0_OUT_A | Tx_Disable | ResetL | |
S0_OUT_B | RS0 | LPMode | Alternatively, RS0 and RS1 be driven to the same level by using just one output. |
S1_OUT_A | RS1 | — | |
S1_OUT_B | General-purpose output, available for any purpose |