DAC - Jitter in SW generator

[u37esp32]

I need to generate a sinusoidal signal and digitize it with an external ADC. The generated frequency and digitization must be strictly synchronous, so I took the ADS1256. It is supposed to use the 8-10 MHz frequency from esp32. If the generator and ADC are operated from a separate frequency source, the process will be synchronous.

For the sine wave generator I want to use the SW generator on DAC1 (# 25). Collected the program according to a typical scheme (similar to https://www.esp32.com/viewtopic.php?t=10321)
For the first tuning, I took a frequency of about 1 kHz. Using the CK8M results in a step = 8 and a frequency of 1038 Hz.
Alternative mode, XTAL / 4 and step = 6 frequency 915 Hz.
In the program, I switched these two operating modes (CK8M / XTAL) every 30 seconds and measure the signal with an oscilloscope (rigol ds1104z). The waveform is correct, as described in the reviews - on the DAC1 there is a switching defect when crossing 0, on the DAC2 there is no defect. Those. esp32 works the same way as everyone else.
Measured the signal frequency:
- CK8M: 1068.17 Hz (.16-.17), independent of anything.
- XTAL/4: 912.7 Hz (.44-.78). When the board was warmed up with a hair dryer, the parity reached 915 Hz. There are no visible defects in the sinusoidal signal.
I intended to use XTAL/4 on the SW oscillator and LEDC to get 8 MHz to set the ADS1256 frequency, this would ensure complete synchronization. But, using XTAL/4 leads to strong jitter (bad) and unstable frequency (not acceptable!).
I would be happy with a job from CK8M, but I don't know how to get CK8M out. The timer output will divide the frequency by 2 and I will get 4 MHz, but I need 8-10 MHz.
Can you tell me if this can be fixed?

(If you implement the output through - periodic timer -> interrupt handler with writing to the DAC, a very stable and correct frequency is obtained. I got 1006.04-.05 Hz)

[u37esp32]

Sorry to bother you, the problem is not esp32. I didn’t work much with DDS generators, and this is their typical drawback. The topic can be deleted.
Thank you.