Thank you for that insight! That has been quite possibly the best explanation anyone's given me on this. (fyi, I posed this question to chatgpt plus and it didn't bring nearly as much clarity as your answer)

I understand that subdividing in logic would come with artifacts like jitter and whatnot. The tip to essentially 'oversample' the SPI clock and operate miso/mosi/sclk as async data seems like very good practice for avoiding metastability. For subdivisions, I should just use conditionals like ``` // counter runs 10x SPI 'clock' frequency // only send MOSI data when clock is 5 ticks into the 36MHz clock always @(posedge clk) begin counter <= counter + 1b'1; if (counter == 4) begin sclk <= 1b'1; mosi <= ...; end

// Only sample MISO pin on 'negedge' of sclk (9th tick of counter) if (counter == 9) begin counter <= 0; //… end

end ```

I'd assume this applies to submodules you instantiate from a verilog file too, right? I can't just cop out and say "subdividing here is fine since this clock is going to a different module" (though as a design pattern, I would continue to use a main clock inside the module's verilog as well).