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                     GPIO/PWM Designations
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All GPIOs are outputs unless otherwise noted. 
By default, GPIOs are driven low during the indicated usage (i.e. LED On state).
D## LED labels apply to the FPGA platform only.

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  I/O  | LED |                   Usage
================================================================
 GPIO0:   D3 - [INPUT with 100uA PD] Undefined. Can use HID commands to change to output low or high.
 GPIO1:  D15 - USB 3.0 Link State if U1/U2 enabled, otherwise [INPUT with 100uA PD]. 
 GPIO5:  D14 - USB 3.0 Link State if U1/U2 enabled, otherwise [INPUT with 100uA PD].
               -----------------------------------
               State: GPIO1/GPIO5 state. 
               -----------------------------------
                  U0: Off/Off.
                  U1: On/Off.
                  U2: Off/On.
                  U3: On/On.
               Other: Off/Off.
 GPIO2:  D13 - HS/FS Suspend.
 GPIO3:   D5 - [INPUT with 100uA PD] Momentary Push Button (for remote wake).
 GPIO4:   D2 - [INPUT with 100uA PD] Bus or Self-powered Indicator. (GPIO level should be HIGH when self-powered)
 GPIO6:   D7 - [INPUT with 100uA PD] Undefined. Can use HID commands to change to output low or high.
 GPIO7:   D1 - SS Connection.
 GPIO8:  N/A - [INPUT] UART Rx. Compile option to configure as output with default state High.
 GPIO9:  N/A - UART Tx.
GPIO10:  N/A - [INPUT with 100uA PU] Undefined. Can use HID commands to change to output low or high. Compile option to configure as SATA Drive Power Enable output.
GPIO11:  N/A - [INPUT with 100uA PU] Power Fault Indicator.
  PWM0:  D12 - Disk Activity (LED blink rate is faster when connected at USB SuperSpeed), USB connection (LED On), and USB Suspend (fading LED). 
  PWM1:   D4 - SW Heartbeat.



