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PSoC™ 5, 3 & 1 Forum Discussions

DaHu_285096
Level 5
Level 5
10 likes received 250 replies posted 100 replies posted

I have a project with 2 x Differential analog input requirement and 2 x Single ended analog input.

The SAR SEQ component is set up as differential input with internal reference for the differential inputs ok.

What is usually done to set the second input for the single ended measurement? I tried connecting to VSSA ref but the program cmplained about vdac output not connected for some reason.

I don't suppose I could put a couple of Digital LOW components on those pins to reference to ground?

Really don't want to waste 2 IO pins to get ground refs.

Thanks

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1 Solution
Len_CONSULTRON
Level 9
Level 9
500 solutions authored 1000 replies posted 750 replies posted

DaHu,

You can use GrC recommendation but you would have to use a SAR + a mux where you control the mux in your code.

The SEQ SAR as BrRu indicated provides compile/build errors when you connect the inputs to anything but a analog pin.

Len

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

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4 Replies
GrC_4053301
Level 1
Level 1
First like given

Drop in a VRef object and change it's reference to GND or whatever you need.

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When I did this, the project would not compile. I got a vdac not connected error

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brockr0-S
Level 4
Level 4
First like received Welcome!

I believe the  sequencing SAR ADC uses the hardware multiplexer that only allows input connections to pins so you will have to connect your two single ended inputs as differential with the second pin going to ground for each pair.

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Len_CONSULTRON
Level 9
Level 9
500 solutions authored 1000 replies posted 750 replies posted

DaHu,

You can use GrC recommendation but you would have to use a SAR + a mux where you control the mux in your code.

The SEQ SAR as BrRu indicated provides compile/build errors when you connect the inputs to anything but a analog pin.

Len

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