Author Topic: Reading out an ADC (ADS8325IBDGKD) with Arduino (ECG monitor)  (Read 1770 times)

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Offline NikWing

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Reading out an ADC (ADS8325IBDGKD) with Arduino (ECG monitor)
« on: December 14, 2013, 03:02:52 pm »
Hello all :)

I'm playing around with an ECG shield for Arduino.
I made this myself using schematics from a magazine and some schematics I found online.
It's kinda split into 2 parts: analog part using OpAmps and optocouplers to decouple it from earth/ground/USB and the ADC part.
The ADC I use is the ADS8325IBDGKD.

The ECG/analog part doesn't work as it should yet at some point, but I'm trying to figure out why (maybe I'll ask about that later, lol).
Right now I want to get the ADC part to work. I want to measure the analog voltage as fast as possible and then send it via serial connection to the PC to make it visible on screen
For this I have to write a little program (using vb.net) to get something like an oscilloscope on screen (either roll mode or updating the screen from left to right)

But what I don't know is how to configure the ADC.
I think the Arduino doesn't have to do much beside reading out the ADC value and sending it along with a time value to the serial port
The time value could be something like millis(), no idea yet if that's a good way to do it :/
But how do I read out the ADC?
I'm a total noob when it comes to reading out sensors. The only thing I did before was reading out DS18B20 temperature sensors using sketches from the www.
So I also have real problems reading the timing information charts in the datasheet :(
But I want to learn how it works :)
The ADC is controlled with 3 pins, DCLOCK (determines conversion speed and syncs the data transfer), /CS_SHDN (chipselect and shutdown mode) and Dout (serial output data word)
Maybe someone has the time to help me out?
Thanks in advance!

Nik

If schematics are needed, I'll post them :)
 

Offline dannyf

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Re: Reading out an ADC (ADS8325IBDGKD) with Arduino (ECG monitor)
« Reply #1 on: December 14, 2013, 03:09:45 pm »
Quote
But what I don't know is how to configure the ADC.
...
But how do I read out the ADC?

Read the adc's datasheet.

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https://dannyelectronics.wordpress.com/
 

Offline NikWing

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Re: Reading out an ADC (ADS8325IBDGKD) with Arduino (ECG monitor)
« Reply #2 on: December 14, 2013, 03:18:39 pm »
I'm a total noob when it comes to reading out sensors. The only thing I did before was reading out DS18B20 temperature sensors using sketches from the www.
So I also have real problems reading the timing information charts in the datasheet :(

thank you for understanding -_-;

I see something like setting /CS_shdn low with DCLOCK, cycling DCLOCK 10 times until Dout throws out the 16 bits data and for some reason Dout has 3 states
and after bit 16 I set /CS_shdn high for 5 cycles and then low again and now I have one value read out, wherever it went :o
Now you see what I meant with the quote above ...
I wish I would find similar projects on the www so I wouldn't have to ask here.
 


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