How does AD974 work?

[zaknwfp]

Does anybody have any idea of how to get AD974 to work. I have tied CS, WR1, and WR2 to ground. I use RC to initiate conversion but for some reason the busy signal does not go low. Any ideas?

 

[logbook]

There are 28 pins, many of which have to be correct for the device to function. Go through them one by one checking for power and grounds first. There are three ground pins

PWRD needs to be low.
EXT/NINT needs to be low.
DATACLK needs to be toggling at say 100kHz square wave.

 

[zaknwfp]

I have all pins connected according to datasheet. I am using external clock so I have EXT/INT tied low. I don't have anything connected to REF except the required capacitor. Does the external clock have to be squre wave. Since I am using I/O pin on a microcontroller for clock its impossible to have a squre wave(i.e 50% duty cycle).

 

[zaknwfp]

A typo above. I meant I have tied EXT/INT to high.

 

[logbook]

I would use a continuous clock from a signal generator to start with as a sanity check, just to get something to happen. Otherwise you might have to resort to a field applications engineer or a colleague to look over the system,. If the part is not recently developed it must be reasonably workable. Either you have wired it up wrong, or you have a duff part.

Change the device to eliminate one possibility. Then you are left with something you can’t see but someone else may see immediately.

 

[automatic2]

your clock should be 50% plus or minus 10. Try pulling your mux wr1 and wr2 lines high. Low indicates your attempting a mux address write.