Still unclear on AD9859, since all family datasheets are iddentical at OSK section. So few questions please:
1. If Shaped OOK is disabled (bypass) from CFR1 it means than OSK pin is don't care, amplitude ON-OFF is no more available at all, unless software modifies ASF register. This is correct ?
2. The auto ramp timer increments at SYS CLOCK ? I saw other DDS specifies 1/4 of SYS CLOCK.
3. The "scale-factor" from ASF[15:14] makes internally counter for ramp increment / decrement x time faster ? If I understand well:
- the max. ramp step size is given by ARR which on AD9859 is 256 or in 400MHz period (2.5nS) means 0.64uS
- the slowest ramp is when ASF[15:14] is 1, meaning 1024 steps for full ASF = 0.64 * 1024 = 655.36 uS
Thanks very much for clarifications