Function poll_diagnostics_on 

pub fn poll_diagnostics_on<T: Transport>(
    port: &mut T,
    socket: Port,
    setup_spins: u32,
    interbyte_spins: u32,
) -> RawPoll

Poll socket once with explicit fixed timing, for hardware diagnostics: setup_spins of delay after asserting the select line, plus interbyte_spins of fixed delay after each byte (bounded STAT reads – no CTRL writes, no /ACK wait, no DSR IRQ). This isolates the two timings a strict original pad (SCPH-1200) might need – setup time after /CS, and an inter-byte gap – without the machinery that corrupted the ack-wait path on silicon.