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AR# 63146

2014.4 XADC Wizard - How to include Vaux4 in the sequence


Not all auxiliary analog channels are available in all device package combinations. 

To check if the Vaux4 channels are available in the Zynq 7000 device that you are using, check the package file for the package you are using. 

If the package file has  *_AD4P_* and *_AD4N_* then the auxiliary channel 4 is available.

There is an issue with the 2014.4 XADC Wizard that does not allow users to include the Vaux4 channel for some packages where the Vaux4 is available. 

The work-around to include the Vaux4 in the Sequence is described below.


To work around this issue in the Wizard, first generate the required XADC setup in the Wizard (minus Vaux4) and generate the Wizard output files.

Then open the .vhdl or .v file generated by the Wizard. This file contains the XADC instantiation.

Search for INIT_49H, which is the second Sequencer register.

In the XADC User Guide see Table 4-2: Sequencer Auxiliary Channel Selection (49h).

Auxiliary channel 4 is BIT 4 of this register.

Change the content to include Vaux4.

For example if you have all other auxiliary channels selected, INIT_49H would be FFEFH.

To add Vaux4 to the sequence you change bit 4, so the new value would be FFFFH.

Similarly if you want ADC Channel Averaging on Vaux4, change bit 4 of 4BH.

To use the bipolar Analog input mode on Vaux4, change bit 4 of 4DH.

To increase the channel settling time to 10 ADCCLK cycles on Vaux4, change bit 4 of 4FH.

You can then remove the .xci file from the project and replace it with the edited .vhdl/.v file.

If you need any assistance with this work-around please open a Webcase.

A second option is to use the patch file included with this Answer Record.

The instructions for installation are included in the readme file in the zip file.


Associated Attachments

Name File Size File Type
63146_Patch.zip 49 KB ZIP
AR# 63146
Date 11/10/2015
Status Active
Type General Article
  • Zynq-7000
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