It seems that this issue has already been raised at this forum. Unfortunately, even though I tried to follow exactly the suggested steps I couldn't get the data successfully delivered to the memory in AD9957. In particular, I'm not sure how to organize the sequence of signals during RAM loading. I tried as follows:
1. CS = low
2. Send RAM address (0x16)
3. Send N 32-bit words one after another (with I/O_Update issued after each of them)
4. CS = high
Sometimes, I see that the first bit is changed but all the other are unaffected by the above procedure.
I will appreciate any suggestions.