Hi,
I was going to suggest increasing the command and/or data delay considerably (say 5000us for command and 200 for data) just to see if it starts to work but perhaps you've already tried that while fiddling with the numbers?

Apart from that it's the usual suspects like ADC and comparators but your device doesn't have any of that on the pins used so that can't be it. So, I think it's either a slow controller or a hardware problem like one of the datalines not reaching the controller.

/Henrik.