We are trying to use the ltc2258-14 with the serial programming mode, Double data rate CMOS. We can not get any output on the clkout line or any of the data lines. We have also been unable to read any of the mode registers.
Any thoughts as to why we wouldn't be getting a response.
Screenshot of attempted spi communication with LTC2258
X"0080", --reset everything X"0203", --set out clock to 45 degree shift and clock stabilization X"0302", --put into double data rate CMOS X"0439", --put into two-compliment data format X"0100", -- Normal Operation X"8300" -- Read Output Mode Register/Output test
Schematic of our board:
R59 has been removed.
Pull Up resistor added to SDO
PAR/SER is connected to ground.
What does the clock signal look like going into ENC+ and ENC-?
We are doing single ended. Clk+ is ENC+
What the duty cycle? That looks like a simulated clock not a scope shot. Can I see a scope shot?
That was from a logic analyzer. Here is the scope shot.
If you are using a single ended clock what are you doing with enc-? Is that shunt resistor removed and ENC- grounded? Have you tried using a test pattern to see if you can get data out that way?