11 Replies Latest reply on Mar 5, 2015 5:52 AM by user_413707516

    GPIO states when bootloader is running




      On my boards I have found that if the bootloader is running (USB boot selected PMODE=F11), some GPIO pins are driven avtively. As an example, GPIO[51] is driven low by the FX3. If the FX3 is hold in reset, the GPIOs seem to be in high impedance state. There are also other GPIOs affected, but GPIO[51] is the one I was investigating since it is important for us that this pin is high impedance state.




      I have found this behaviour of GPIO[51] on our custom hardware with the CYUSB3014 production code 1149 and the Cypress Rev 2 DVK Kit having production code 1113. Has somebody else also observed such behaviour?




      At this point I would like to get a statement from Cypress, how the bootloader is initialising the GPIOs. As you guys have access to the bootloader code, it should be easy enough to tell us. Thanks.