I want to connect a LED to GPIO Pin.
Which maximum current I'm able to use?
Which device are you trying to use? Could you be more specific? Moreover what is the drop across the Led. typically Leds will require anout 10mA of current. If your chip is say operating at 5V and if the drop across the Led is 1V, if you choose a resistor of 470ohm, you will get a current close to 10mA.
This I am interested as well and wasn't able to get a clear statement from Cypress so far. In the datasheet the I/O pins are tested only at 100 uA. Hopefully we can get a bit more current than that....
The drive strength of the GPIOs of FX3 is configurable. It rated for 13mA if configured for full drive strength.
LEDs have current ratings you've to select the drive strength configuration based on the LED you'll be using.