Hi Joel:
Thanks your help.
Yes my PFD frequency is 20 MHz.
There is no low pass filter on the spi Port .
But I decrease the high level to 2V ,It's work.
I think the "1" logic is higher before,so I have to change the spi Port circuit.
Thanks again.
Hi Joel:
Thanks your help.
Yes my PFD frequency is 20 MHz.
There is no low pass filter on the spi Port .
But I decrease the high level to 2V ,It's work.
I think the "1" logic is higher before,so I have to change the spi Port circuit.
Thanks again.