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PSoC™ 5, 3 & 1

New Contributor

I am using 5LP and need 1.024V Vref in the schematic.

Because all 4 Comparators are used, I am not allowed to "AutoEnable" the 1.024V Vref, the Datasheet says Vref needs to be manually enabled in analog block.

But I cannot find the instructions for how to manually enable Vref.

Can someone help me on this?


1 Solution
Honored Contributor II


I'm back.

I performed some experiments and have some suggestions.

Attached is a project based on your original design intent.  It has three schematic sheets.  Enable only one sheet at a time.  Disable the enabled sheet first, then enable the next sheet.  Perform a build.

The application in main() switches the AMux_1 one channel every 1 second and displays the mV reading using the DEBUG_UART @ 115.2Kps.

The "sch" is a modification of your original design (See pic below).  I included 3000mV and 500mV VDAC sources to drive the channels 0 and 1 of AMux_1.

The 1.024V Vref is not AutoEnabled.  The resultant channel 3 voltage reading is 1824mV.  There is also a Opamp follower mode on the output of the AMux_1 to see the result of the mux on a scope.


The "VDAC" sheet (See pic below) replaces the 1.024V Vref with a VDAC generating 1.020V.  The resultant channel 3 reading is about 1042mV.  This is more on target.


The final "VFD" sheet (See pic below) keeps the 1.024V Vref on channel 3 with it AutoEnable'd.  It does replace Comp_1, Comp_2,  Comp_3 and Comp_4 with a 4-channel VFD component.  The resultant channel 3 voltage is about 1042mV.  I did not fully configure the VFD so it may not be working to intended spec.

By the way, Cypress provides a PowerMonitor that provides ADC readings and input voltage fault detection of various types.


Maybe one of these ideas will work for you.


"Engineering is an Art. The Art of Compromise."

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