PSoC 5, 3 & 1 MCU

[Anonymous]

      Hello everyone,   

       

     Greeting!   

       

     I'm trying to apply PSoC 5LP: CY8C58LP Family to my sensors system.  But I have no idea whether the sensors can match the GPIOs.   

       

     There is a High Impedance drive mode of GPIOs. But I can't find any value of how high they can be from the datasheet.    

   

    
Here are our sensors specifications:
The sensors are designed by us by putting a piece of plastic foil between two pieces of metal foils and gluing them together. It’s used as pressure sensors. The peak to peak output voltage with touch is about 400 mV. The peak to peak output voltage without touch is about 30 mV. The average output voltage with touch is 16mV. The average output voltage without touch is 9mV. The output impedance is 30 meg ohm.    

   

    
Could you please give some ideas of how to verify these specifications and see if I could directly connect the sensors to PSoC?    

       

     Thank you so much! Looking forward to your reply!   

       

    My mail address is mmrnc@mail.missouri.edu. I'm so glad if you could reply my post or send me mail.   

[JoMe_264151]

Welcome in the fascinating world of PSoCs!

   

Some considerations beforehand:

   

What is the needed accuracy and what is the required precision. What is the wanted conversion time and how many of that sensors do you wand to connect.

   

The analog DC input impedance is in the order of GOhms, so probably not an issue.

   

The resolution of the ADCs go up to 20bits, subtract some because you might not be able to use the full-scale.

   

Noise can be an issue, to when speed allows, you may averace measures.

       

Hope that helps!

   

Bob

[ETRO_SSN583]

You might take a look at -

           

http://www.cypress.com/?rID=49159     AN66444

   

http://www.cypress.com/?rID=2894     AN2226

       

Also consider using sensor in one arm of a bridge, to get rid

   

of CM signlas given you are at such a high Z interface and hence

   

prone to pickup/stray coupling.

       

Regards, Dana.

[ETRO_SSN583]

Here is some reference material for IAs, attached.

       

Regards, Dana.

[Anonymous]

 Thanks a lot! I think I know how to verify it. Let me try it.