These A/D systems use methods to isolate the sensitive analog signals
from the electrical noise and ground plane of the computer. Typically a
differential input is standard, so you will probably need wire up two
inputs.
If this is your first time with A/D, suggest you toggle in some code to
trigger and report the A/D conversion repeatedly and use a small voltage
battery with a potentiometer divider to drive the inputs. Most of
the analog inputs should be high impedance and while not impervious, can
take +- 30v w/o damage.
Jerry
On 2/6/22 11:43 AM, Douglas Taylor via cctalk wrote:
Yes, I am putting 1 into the CSR to start the conversion and I do get
a 200(8) indicating that the conversion is complete. I wonder if this
means the A/D chip is OK but something else, like the multiplexer chip
or gain amp is fried.
On 2/6/2022 12:33 PM, Jerry Weiss via cctalk wrote:
Are you triggering an A/D conversion via the CSR or external signal?
Then check the A/D done bit.
See EK-AXV11-UG-02 Chapter 4.
Jerry
On 2/6/22 11:20 AM, Douglas Taylor via cctalk wrote:
I have one of these and would like to use it, however it appears to
only partially work. Here is what I have found that works and what
doesn't:
1. CSR and DBR are present and operational.
2. Jumpers set to 'factory'.
3. D/A portion works, can deposit codes in ODT and see voltages out
on DAC pins that change depending on the octal value deposited in
CSR+4 or +6.
4. A/D portion returns full scale code, either 3777 (2's compliment)
or 7777 (offset binary) whether in the input is open or shorted to gnd.
I think the problem is that the A/D inputs are not exactly protected
and damage has occurred to this portion in the past.
Does anyone have any info on the A/D module? Who made it? Can you
open it up? Does XXDP have a test for this?
Doug
