1 Reply Latest reply on Jul 1, 2013 3:50 AM by user_44074550

    Incremental ADC Implementation on PSoC4

    psai

      An attempt has been made to implement an Incremental ADC on PSoC4, based on the Topology No. 3 provided by Dave Van Ess in the below article in EE Times:

         

       

         

      http://electronicdesign.com/analog/my-favorite-modulator-only-needs-leftover-components

         

       

         

      Attached is the PSoC Creator project demonstrating this. Though a 16-bit result is generated, the ADC result is reduced to 12-bit and displayed to reduce noise.

         

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      Steps to test this project on a PSoC4 Pioneer Kit (CY8CKIT-042):

         

      1) Build this project and program it into the Pioneer kit.

         

      2) As shown in the scehmatic, make the following connections to complete the Delta Sigma modulator: (a) Connect an external 100K resistor between P0[7] and P0[4].    (b) Connect a 0.1 nF capacitor between P0[4] and ground.

         

      3) Connect an Analog Input to P0[5].

         

      4) Connect P4[1](on J3) of PSoC4 to P12[6] of PSoC5LP(J8). This connection is for sending ADC result using PSoC4 UART through PSoC5LP(which acts as USBUART bridge) to PC.

         

      5) Connect USBmini cable betwee the Pioneer kit and PC.

         

      6) Open a terminal application on PC(such as Hyperterminal/Teraterm etc). In the terminal application, select the port corresponding to the name "KitProg USB-UART". Set Baud Rate = 115200, Data = 8 bit, Parity = None, Stop Bit =1, Flow Control = None.

         

      7) Vary the Analog input between 0 - Vdd, and observe the 12-bit result on the terminal application

         

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      Though 4 UDBs have been used in this project, it can be reduced to just 1 UDB/TCPWM block if the PWM is replaced using the clock dividers available in PSoC4 and just an 8-bit counter is used(the MSB 8-bits of the counter can be implemented as a firmware byte which is incremented on the 8-bit counter's interrupts).

         

      Thanks & Regards,

         

      Prem Sai