I disconnected the databus, then I measure the voltage on the databus pin,they are 3.3 volt.
I ground one of them for a while and them left it not connect. But the voltage on the pin is still 3.3 volt. So I think the databus is outputting. Even though I set it not drive in idle state in register through register GPIFIDLECS.
Need a little more information to understand this issue better
When you connect FX2LP to the external FIFO then FX2LP doesn't enumerate? or renumerate (firmware download works but FX2LP doesn't enumerate back)?
I've seen issues like this happen when pins of FX2LP are being driven when the chip is not powered. Are you driving any of the pins of FX2LP when the chip is still not powered?
it can't renumerate,(firmware download works but FX2LP doesn't enumerate back)
yes, to decrease the control line to external FIFO. The OE pin of external FIFO is grounded. It means it is driven when the external FIFO be powered. 68013 is powered when it connects to PC.
I will try this.
Is it happening with all firmwares i.e. can you download one of our example firmware with the external FIFO connected to see if it renumerates or not?
I just want to find out if the firmware is stuck somewhere due to the databus being driven.