UltraScale devices have pins dedicated to the configuration functions contained in I/O bank 0. There are also I/O pins in bank 65 (multi-function configuration bank) known as multi-function or multipurpose pins that can be used for configuration and converted to programmable I/O pins after configuration is complete. Additionally, during configuration of devices with multiple super logic regions (SLRs), the pins in bank 60 and bank 70 have restrictions similar to the multi-function pins. The restrictions on these banks are required even though they are not configuration banks.
During configuration, I/O drivers are 3-stated in all banks except the banks used for configuration (bank 0 and bank 65) and the aforementioned bank 60 and bank 70 in devices with multiple SLRs. During configuration (until the applications settings take over), all HP I/O banks use the default IOSTANDARD = LVCMOS18, SLEW = FAST, and DRIVE = 12 mA setting. The corresponding setting in HR I/O banks is IOSTANDARD = LVCMOS25, SLEW = FAST, and DRIVE = 12 mA. After configuration, the unconfigured I/Os have 3-stated drivers and the pads are weakly pulled-down.
In devices where bank 65 (all devices) and bank 70 (only devices with multiple SLRs) are HR I/O banks and configured with a VCCO requirement £1.8V, the inputs can have 0-1-0 transition to the interconnect logic during configuration if the input is tied to a 0 or floated and the configuration voltage is ³2.5V. For further details, see the UltraScale Architecture Configuration User Guide (UG570) [Ref 4].
UltraScale (not UltraScale+) devices with multiple SLRs can have the weak pull-up temporarily enabled on I/Os in the slave SLR during the configuration sequence (between power on and assertion of the INIT_B configuration signal). In some boards, this can cause an undesired 0-1-0 transition on I/O in the slave SLR. It is recommended that any I/O pins in the slave SLR sensitive to a 0-1-0 transition during configuration be connected to I/Os in the master SLR or include external pull-downs of 1 kW or stronger to the pin.