AnsweredAssumed Answered

AD5292 in daisy chain

Question asked by ADevice_User on Apr 6, 2016
Latest reply on Apr 17, 2016 by ADevice_User

Hallo everybody,

We're trying to control two AD5292 in daisy chain mode. I'm sending pictures of the SPI. First we send command {0x1802 & 0x0000} to enable calibration and then {0x0500 & 0x0000} to change wiperposition of the second AD in the chain. SPI looks fine to me, but the devices just don't work.

 

The first picture shows the sync and the clk signals.

The second picture shows command „enable calibration“.

 

The board i'm using was already set up, bevore i started to work with it.


This is our set up:

----------------SET UP-------------------

V_Supply: 12 V

V_Logic: 5 V


RESET: tied to Vlogic-Pin.

 

VSS: connected to negative V_Supply and decoupled with one 0,1 µF capacitor to GND.


VDD: connected to positive V_Supply and decoupled with one 0,1 µF capacitor to GND.


EXT_CAP: Connected with a 1µF capacitor to GND.


VLOGIC: Connceted to positive V_Logic and decoupled with one 0,1 µF capacitor to GND.


SDO of the first AD in DaisyChain: 20 kOhm pull up Resistor to posive V_Logic and 15 pF capacitor to GND. Connected to DIN of the second AD in DaisyChain.

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For me two things look a little incorrect, since they are not in accordance with the datasheet: the EXT_CAP and the SDO of the first AD. Is the the set up possible this way?

Thank you in advance!

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