1.) You can go ahead and use the I2S as GPIO's after overriding them since they are taken out to the expansion header as GPIO50,51,52.
But the UART interface pins are routed to another chip on the CX3 Denebola kit as shown below:
You can override the GPIO's and would need to take the outputs/inputs from these pins as above.
But if you are using a custom board, you can override them and use them as GPIO's.
2.) Please refer to section 11 Default State of I/Os During Boot of the app note AN76405 from the following link: https://www.cypress.com/file/201991/download
Thanks for your feedback!
I will use it in a custom board.
but I still have questions regarding IO
1. Can all these IO be used a interrupt input?
2. If using IO to simulate PWM wave via software, what is max frequency for this PWM?
--> You can configure all the 60 GPIO's as Simple GPIO's with Interrupt functionality.
But the concept of configuring complex GPIO's from the total 60 GPIO's is mentioned in the above snapshot.
2.) Please refer to the firmware provided in FX3 SDK for configuring a complex GPIO from the path: C:\Program Files (x86)\Cypress\EZ-USB FX3 SDK\1.3\firmware\serialif_examples\cyfxgpiocomplexapp
The above example uses a 1KHz PWM signal on GPIO as ouput.
Also, for more info on the PWM configuration, you can refer to the following KBA: Calculating PWM Period and Duty Cycle in FX3 – KBA226759
For more detailed info, please refer to the answer of the following thread: Re: generating pwm on fx3
The max possible PWM frequency is ~50MHz as mentioned in the above threads.