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PSoC 5, 3 & 1 MCU

New Contributor

I'm trying to route a reference voltage to an analog multiplexer as shown below but PSOC creator is throwing errors.

Is this at all possible? If so, how?

pastedImage_0.png

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Honored Contributor

Surfer,

I've looked at the Cypress info available.  In general, the SIO pins (Port 12) are very versatile but have the limitation that they don't support analog input and indirectly support analog output.

I've included a snippet of a circuit that might be what you intended.  It requires one more pin to achieve.

pastedImage_0.png

In this configuration, vo_ref puts out a vref-limited digital output (<1.024V) with about 1mA drive outside the PSoC.  vo_meas measures the resultant voltage (1.024V -0.5V [depending on the load on vo_ref]).

Hopefully this will address your design issue.

Len

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

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Moderator
Moderator

Described in datasheet: "Currently, only the GPIOs can be multiplexed with this multiplexer."

The software analog mux can be used for routing the vref signals.

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Honored Contributor

Surfer,

Can you supply some info about your use of the pin 12.2 called vo_meas?

It appears you are trying to use this pin in SIO mode.  According to https://www.cypress.com/documentation/application-notes/an60580-sio-tips-and-tricks-psoc-3-psoc-5lp

analog functions are not supported if you are using the vref input.  This input is intended for thresholding for digital inputs or outputs.

Len

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

Surfer,

I've looked at the Cypress info available.  In general, the SIO pins (Port 12) are very versatile but have the limitation that they don't support analog input and indirectly support analog output.

I've included a snippet of a circuit that might be what you intended.  It requires one more pin to achieve.

pastedImage_0.png

In this configuration, vo_ref puts out a vref-limited digital output (<1.024V) with about 1mA drive outside the PSoC.  vo_meas measures the resultant voltage (1.024V -0.5V [depending on the load on vo_ref]).

Hopefully this will address your design issue.

Len

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

View solution in original post

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