This will create virtaul pins 400-415 using two DNIN8 boards connected in sequence.
Vpins 400-407 will be on the first board (closest to the CS) and 408-415 on the second.
Note: 16 pins uses two boards. You may specify a non-multiple-of-8 pins but this will be rounded up to a multiple of 8 and you must connect ONLY the number of boards that this takes.
This example uses Arduino GPIO pins 40,42,44 as these are conveniently side-by-side on a Mega which is easier when you are using a 3 strand cable.
The DNIN8K module works the same but you must use DNIN8K in the HAL setup instead of DNIN8. NO you cant mix 8 and 8k versions in the same string of boards but you can create another string of boards.