When XPIO banking resources are located adjacent to certain resources such as
the processing system (PS) or high-speed transceiver columns, the XPIO bank have limited
functionality. Because these restricted XPIO banks are typically located at the corners
of a device, they are referred to as corner banks.
Corner bank locations vary by device and are explicitly called out in the
Versal
ACAP Packaging and Pinouts Architecture Manual (AM013) with a DDRMC designation. Following are considerations when working with corner
banks:
- Although clocking pins (GC) in corner banks have full access to clocking resources, non-clocking pins are restricted to the memory controller (DDRMC) functionality. Though usually defined along bank boundaries, in some instances a partial bank on nibble boundaries might be restricted to DDRMC use.
- In pin planning a Versal ACAP design, use corner banks for DDRMC interfaces only. When using the Advanced I/O Planner for Advanced I/O Wizard designs, the corner banks are blocked from use.
- Where GC inputs are used to drive XPIO corner banks, clock buffers BUFGCTRL and BUFGCE_DIV cannot be placed after MMCM because the sites are reserved. The corner bank affected is below the PS (bottom left corner) and does not have full access to programmable logic resources. There is no restriction for the corner bank below the GTs at the bottom right corner.
- When you need to use an MMCM in the restricted corner bank, the MMCM output clock must go through a BUFGCE to reach any other loads, including BUFGCTRL or BUFGCE_DIV.