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greatmaverick
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Explorer
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Registered: ‎04-06-2017

Two ADCs in XADC work together

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For 7 series FPGA, if ADCA and ADCB in XADC work together, what the channel outputs which tell us the last conversion channel will be delivered? the channel in ADCA or ADCB? It happens in the independent mode and simultaneious mode.

Thank you

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pthakare
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Registered: ‎08-08-2017

Hi @greatmaverick 

In the independent ADC mode, ADC A is used to implement a fixed “monitoring mode” similar to the default mode, When you look to the default mode the sampling sequence is Calibration , Temp, VCCINT, VCCAUX and VCCBRAM

pthakare_0-1612507377180.png

 

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pthakare
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Registered: ‎08-08-2017

HI @greatmaverick 

The CHANNEL_OUT[4:0] in this case inform the last conversion on ADCA (Default ADC). 

you can confirm this by running the example design for independent mode configuration and check the  CHANNEL_OUT[4:0] in simulation.

The example design is create by right click to XADC IP instance -> Open example design.

 

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greatmaverick
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Registered: ‎04-06-2017

Thank you. 

This can be understood for simultaneous mode. If I see an eco assertion, I can initiate 2 consecutive DRP read operations for the ADCA and ADCB conversion results.  But it may not be true for independent mode because the end of conversion for ADCA and ADCB may not happen at the same time as to my understanding. The user guide has not said ADCA and ADCB convert simultanously.

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pthakare
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Moderator
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Registered: ‎08-08-2017

Hi @greatmaverick 

Looking at the timing details for Independent mode from UG480 , ADCA and ADCB conversion seems to happen at the same time. Again this can be verified by ADCB operating in continuous channel mode.

I will try to check this at my end so confirm my understanding.

pthakare_0-1612338812080.png

 

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greatmaverick
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Registered: ‎04-06-2017

I have simulated XADC operating at the the independent ADC mode, finding the channel output is the external channel sampled by ADCB. I do not know what is the ADCA sampling sequence. This is important when using XADC

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pthakare
Moderator
Moderator
301 Views
Registered: ‎08-08-2017

Hi @greatmaverick 

In the independent ADC mode, ADC A is used to implement a fixed “monitoring mode” similar to the default mode, When you look to the default mode the sampling sequence is Calibration , Temp, VCCINT, VCCAUX and VCCBRAM

pthakare_0-1612507377180.png

 

-------------------------------------------------------------------------------------------------------------------------------
Reply if you have any queries, give kudos and accept as solution
-------------------------------------------------------------------------------------------------------------------------------

View solution in original post

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