What is the max. output frequency from the on-chip DDS of the ADuC7128/29 ?
Basically this is related to the DDS settings and theoretically from this settings,
as can be seen on page 47 in the datasheet, the frequency can be calculated.
FSW = Frequency Select Word
1 LSB in the 32-Bit DDSFRQ MMR is equal to 0.0048 Hz
So the total range controllable by SW is from
0.0048Hz to 20.8896MHz
But the DAC output driven from the DDS has a subsequent Low-Pass-Filter (LPF) on the chip.
This LPF determines the max. output frequency as specified in the datasheet on page 4
to a -3dB cut-off point at 1MHz.