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Eval-AD7609EDZ use in standalone

Question asked by steverey8 on Feb 12, 2014
Latest reply on Feb 14, 2014 by steverey8

Hello all,


My name is Steve and I am needing some help using the AD7609 in general.  My group is working on a project which we need to measure about 14 different DC voltages and input them into an FPGA.  We decided to go with the AD7609 as we do not have many GPIO ports on our FPGA.  Just a standard 40 pin connector (Minus 4 pins for 5V, 3.3V, and [2] GND).  Maybe there's a better way to measure these voltages, but this seems like the easiest for us.  As we are new to FPGA's we want to go ahead and convert the analog voltage measurements into binary data.


Moving along to our problem.  We received the Eval-AD7609EDZ from Analog Devices and continued to look for documentation on it.  The document which we found explains the setup process and how to use the Eval-AD7609EDZ in conjunction with EVAL-CED1Z, which then connects to a PC that controls and analyzes the readings.  The documentation doesn't really go into explanation of how to use the board in standalone mode, it just mentions that it has the capability of doing so.


So as far as setup is concerned.  I went ahead and did continuity checks to find out which pins from the AD7609 went to the 96 pin connector on the Eval board.  I am attaching the layout I came out with:


This is the setup I did to verify functionality:

AVcc - 5VDC, one pin connected to voltage source

VDrive - 3.3VDC, one pin connected to voltage source

Ground - All ground pins seemed to be connected together, so only one pin went to ground

DB0-DB15 - Connected to LED, then ground

Range - Tied to high

STBY - Tied to high

CS and RD - Connected to a pulse switch, normally high

Reset - Connected to a pulse switch, normally high

CONVST - connected to a pulse switch, normally high

OS - Left open


For analog inputs,

V- tied to ground

V+ tied to 5VDC


We tried manually controlling the AD7609 by switching reset, then CONVST, then pulsing CS/RD.


LED's would not light up, and we never received a FirstData signal.