...
If you still don't get any feedback from the chip, please double check that the RSTn is kept at 18V for at least 1s before your first command to the chip.
...
I think you mean 1.8V !
Sure 1.8V.
But from the datasheet it states that signal is active low. So it must be kept for 1s 0V. Or do you mean that after it goes 0V for 1s it must be kept at 1.8V for another 1s before first command?