3 Replies Latest reply on Jun 25, 2018 11:42 PM by rajivb_36

    PSOC 4 thermistor interface

    rajakumar.r_2227736

      Hi I want to interface thermistor with PSOC4 . so i am using cypress example program.

      i am using 10k thermistor . while using this example project i am getting some random outputs. kindly help me to resolve this. i have attached the thermistor data sheet and program.

       

       

      thermistor part number:B57540G1103H000.

      psoc kit used :CY8CKIT-042

       

       

      thanks and regards

      Rajakumar

        • 1. Re: PSOC 4 thermistor interface
          e.pratt_1639216

          Well, you are polling for the ADC to finish, I don't believe you need to call ADC_StopConvert(); afterwards, as it only returns if it completed the ADC conversion. That might be why it is causing randoms values to spit out?

           

          Just as an FYI, Modulus operations (% symbol) are very slow in programs, so if you want better performance/speeds, trying not to use it is preferable.

           

          Try debugging the program with the SWD ports, and see what values the RAM are showing for iTemp, iRes, and how the filtering.

          • 2. Re: PSOC 4 thermistor interface
            user_13463998

            Dear Rajakumar-san,

             

            Since I could not figure out your top circuit, I'll put my temp test project (for CY8CKIT-044).

            May be you need to recreate the project for -042.

             

            My top circuit is

            TempSense.JPG

            And as "B" parameter of my therm is different from yours,

            please modify line 24 of main.c from

            #define B 3435

            to

            #define B 3492

             

            And as I'm using log(), we need to add command line "-lm" in Build Settings Compiler and Linker

            Compiler_command_line.JPG

            Linker_Command_line.JPG

             

            Hope this can be a bit of hint/help.

             

            Best Regards,

            26-Jun-2018

            moto

            • 3. Re: PSOC 4 thermistor interface
              rajivb_36

              Rajakumar,

               

              Your project seems to be working fine. Can you please check the following?

              1. See if the bias voltage is applied

              2. Check the connection from P4[1] on header J3 to PSoC 5LP's P12[6] on header J8 for UART

               

              Also, please check if you can make a change in firmware as suggested by other members.

               

              -Rajiv