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Re: Re: AD7606: Inconsistent output value

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Hi Jonathan

 

Thanks a lot for checking this issue out.

 

1. To confirm on the reference used: External.

 

Could you please clarify my confusion on this.

The data sheet [attached earlier] says R5 inserted, hence Internal reference mode [Page 5, Table 3, of the Eval data sheet.]

but from the Board itself, please refer to the image below.

I think external reference is used.

 

R6 inserted, R20 not clear.

 

Internal_Exter_Ref.png

 

2. To clarify on the SCLK clocks:

In the Timing diagram picture 1, we can see that there are 16 spikes observer in the Clock. This is at 1ms time resolution. The picture 2 is a zoomed version, of 10us time resolution, so it shows one of those 16 spikes with 8 clocks in it.

16 * 8 = 128 Clocks to read all 8 channels

 

Reason why continuous 16 clocks are not seen:

Note: Arduino uses int raw = SPI.transfer(0x00); code to read data from SPI. This gives out only 1 byte at a time, need 2 bytes per channel. So I run it in a loop of 16 times to read all 8 channels so you don't see a continuous 16 clocks but 2 sets of 8 clocks each per channel.

 

Note: There are additional Images of various Time resolutions attached along with that timing diagram images.

 

3. Right now I have connected only 1 channel, rest are tied to AGND through the LK2 ~ LK8.

Do I still need to apply 128 clocks or I can just apply 16 clocks.

 

 

Regards,

Simba


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