6 Replies Latest reply on Oct 24, 2018 11:24 PM by user_1269049

    CY8C4245-AXI clock does not run at 48MHz

    user_1269049

      I have build several identical custom boards with a CY8C4245AXI. On some boards I notice that the controller does not run as fast as it should.

      I have removed all parts except the capacitors for the controller, still the controller is slow.

      The controller is powered by the Miniprog3.

      A test application only has a timer and one output pin.

      There are no warnings during build.

      Here is what I observe:

       

      clock set to 48MHZ

      timer should generate a 200kHz signal

      running at 3.3V: output signal is 59kHz (slow)

      running at 2.5V: output signal is 200kHz (ok)

       

      clock changed to 24MHz

      output signal now should bei 100kHz

      running at 3.3V: output signal is still 59kHz (same as with 48MHz clock!)

      running at 2.5V: output signal is 100kHZ (ok)

       

      I have at least 5 controllers that show this behaviour. And there are about 20 other controllers that run as expected.

       

      Why do some controllers run slowly at 3.3V?