4 Replies Latest reply on Oct 12, 2020 10:12 AM by JoCh_1493306

    ModusToolbox Power Dropout Warning




      I am doing some development on CY8CKIT-062-WiFi-BT using ModusToolbox Version 2.2.0. I am testing some SPI features. When I built the program it built ok. But When I programmed it into the dev board, it gave me a warning


      "Power dropout, target voltage: 2.772 mV

      Info : Power dropout detected, running power_dropout proc."


      I checked SW5 and it's in the middle position, which is 3.3V.\


      Any idea what this warning mean and how to get rid of it?

        • 1. Re: ModusToolbox Power Dropout Warning

          Hi JoCh_1493306


          Can you check if the power monitoring jumper, J8 (bottom layer of the board) is in place? Also verify if the Vbackup switch, SW7 is set to VDD/KitProg instead of SuperCap.


          Please measure the actual voltage on the VDD line and verify that it is 3.3V.


          One additional test is to use Cypress programmer and try to acquire the device. This will indicate if it is an MTB issue or a hardware bug.

          Best regards,

          • 2. Re: ModusToolbox Power Dropout Warning

            Hi Hari,


            I checked SW7 and it was set to VDD/KitProg correctly. But I could not find J8 in the bottom layer of the board for some reason.


            Actually more information about this issue: I had an Ethernet shield connected to the CY8CKIT-062-WiFi-BT dev board. The way I connected them together was simply mate all the pins on the Ethernet shield to the receptors on the dev board. When I programmed the dev board (with just the Hello World program, not using the Ethernet shield at all just for testing), it gave me that power dropout warning.


            I just tried to disconnect the shield from the dev board. Then I used some jumper wires to just connect the power and ground to the shield, then I programmed it and the warning was gone. It seems to me somehow when the shield was fully connected to the dev board, it drew lots of the current out from the dev board and caused the power dropout.



            • 3. Re: ModusToolbox Power Dropout Warning



              Besides the CY8CKIT-062-WiFi-BT, is there anything attached to the development board?


              It might be possible to drag down the VDD programming voltage being supplied by the USB cable through the KitProg section of the board.  This would be a device externally connected to the dev board through the headers for example.


              If this could be the case, I recommend for now to remove any external connected boards or devices to program the dev board.


              Note: As per USB convention, the USB power that can be used to power circuits is limited to 500mA.  For devices that require more current than this, you must supply the power from another source.   This is particularly true for USB hard drive devices where the motor startup current can be in excess of 3A.


              It can be possible to be close to the 500mA limit and the upstream regulated voltage supply from the PC through the USB cable is dropping too low to program the CY8CKIT-062-WiFi-BT.



              • 4. Re: ModusToolbox Power Dropout Warning

                Hi Len,


                Yeah there was an Ethernet shield attached to the top of the dev board. After I removed it the power drop out warning was gone. Seems like somehow the Ethernet shield drew too much current from the dev board if fully connected.


                After I removed the shield, I used jumper wires to connect just a couple pins (for SPI communication) and just power and ground. There was no issue any more.