how about for setting the OUTSET bits? I have this currently:
    let p_outset = (0x5000_0000 + 0x508) as *mut u32;
    unsafe {
        *p_outset |= 1 << 20; // row1
        *p_outset |= 0 << 27; // col1
    }


attempting to set 21 and 28