Hi all,
We are using 25 MHz external oscillator for UB960 reference clock. Amplitude of input clock is about 500 mV (image below):
But, in UB960 datasheet minimal amplitude is 800 mV:
So, I was unable to detect refclk valid frequency - value in DEVICE_STS register (Address 0x04) was 0xC0 (REFCLK_VALID bit is 0).
After I removed resistor R13, amplitude of clock has increased and I'm able to detect refclk - value in register DEVICE_STS register is 0xD0.
But, if I read register REFCLK_FREQ (Address 0xA5) I'm getting value 0x1A = 26 MHz. With oscilloscope I can clearly see 25 MHz clock at REFCLK pin.
Do you know what is the problem?
Best regards,
Stefan.
