Send signal to FPGA from an ESP32

[Raist71]

I want to send several signal to a FPGA device (about 20 signal).
I don't want (if possible) to add some equipment between ESP32S and FPGA.
Both work at 3,3 V, ground are connected.

1) Question 1
If I set GPIO_DRIVE_CAP_0 on the pins I use, I'm in save mode (current point of view) ?
Or in any case I need to add some resistor (or something else) for the transient (pin on/off)?
Because in theory I shall have max 10 mA, right ?

2) Question 2
I have tryed to find some info about how work GPIO_DRIVE_CAP, but I don't find, can someone give some link about that ?

I hope I have explained myself.
Thanks

[MicroController]

1) Question 1
If I set GPIO_DRIVE_CAP_0 on the pins I use, I'm in save mode (current point of view) ?

Depends on the length of the connections, the frequency you want to transmit at, the input impedance of the FPGA, the impedance of the connections, and the acceptable levels of emitted EMI.

[Raist71]

FIRST: For me FPGA and Electronic in general are Hobby, not work. I read too much times the word FPGA and I decide to understand what it is I study a lot, but it's not my job. (the same for the word ESP )

Second, the Data:
Thee length it's 30 cm max.
Frequency (it's a demo board) Starting point 10 Hz. Perhaps I can arrive to 2k Hz.
EMI: I do not consider.
Impedance: I don't know. Impedance of the pin. It's HIGH, but I don't found the value...
I only know the Cpin = 10 pF (approx)

[Sprite]

Honestly, you're sending a 3.3V output to a 3.3V capable input. Especially when there's no need to keep EMC in mind, your lines are short, and your signals are low-frequency (say <50MHz), there's not really any wrong choice you can make. Just go with the defaults and it'll be fine, and optionally tweak the output capabilities if you find out you need a different slew rate.

[Raist71]

Perfect, thanks !

About question 2 ?
2) Question 2
I have tried to find some info about how work GPIO_DRIVE_CAP, but I don't find, can someone give some link about that ?

[MicroController]

Hobbyist here too. That's why I go by the rule of thumb to keep connections (significantly) shorter than the wavelength of the signals in order to stay clear of most of the impedance-messiness. This rule tells me that at 2kHz you'll be fine as long as you stay well below 150km of wire length

(If you had said, for example, that you wanted 40MHz SPI communication with the FPGA, which isn't much of an exotic or unrealistic use case, slew rates and impedances could have been more relevant, as @Sprite indicated.)