6 Replies Latest reply on Jul 30, 2019 5:07 PM by dacx_4333566

    Any idea to process 0.01Hz in PWM?

    dacx_4333566

      Good day,

      I am newbie to PsoC. Recently, I am doing a project of improving impedance meter(original resources: Chris Keeser) which able to process with 0.01Hz frequency by using PSoC 5LP Developing Kit. The figures below shows the TopDesign analog circuit and digital circuit:

      1.PNGAnalog Circuit

      2.PNG

      Digital Circuit

      The frequencies were generated by using Divider(PWM) with the frequencies range 0.01Hz, 0.10Hz, 0.20Hz, 0.50Hz, 1.0Hz, 2.0Hz, 5.0Hz, 10.0Hz, 50.0Hz and 100.0Hz and the periods(in micro second) write into Divider are 250000, 25780, 12890, 5155, 2577, 1288, 515, 257, 51 and 25 respectively to the frequencies.

      The problem discovered from the data sheet of Pulse Width Modulation was the range of period count can be wrote for the divider maximum for 16 bits wide resolution where the period assigned for 0.01Hz is 250000 which exceed the 16 bit wide range and the frequencies measured with oscilloscope showing the value x100Hz than the frequencies needed and waveform showing unstable at 100Hz.

      Is there any suggestion for process the 0.01Hz to the circuit in another ways and solve the problems of generating correct frequencies?

       

      Thank you.

       

      Dawn