alt Hacker NewsI think you miss understood the challenge. They are using a 60Msps ADC with a parallel port interface. The challenge is capturing the 600Mbit/s of data and having enough CPU and memory bandwidth to do anything useful with it.
If your microcontroller has a parallel port interface, you would use the clock setup you described. This works, I've done it before, but there was very little CPU left to do anything useful with the data.
It's neat that they used the PIO, its demonstrating how that peripheral fills a niche where you things that might have been impossible without an FPGA, suddenly become doable on a microcontroller.
Well, parallel port adc capture has nothing to do with PIO either - on STM32 you would just set up DMA on a GPIO port, then capture 16bit data. The real question is what RP2040 is going to do with 120MB/s of data.. and the answer is, it can't process it or send it over (12Mbps aka 1.5MB/s) USB. So, would only work in low duty cycle pulse mode, no streaming.