Rules for Combining I/O Standards in the Same Bank - Rules for Combining I/O Standards in the Same Bank - UG861

The following rules must be obeyed to combine different input, output, and bidirectional standards in the same bank:

1. Combining output standards only. Output standards with the same output V_CCO requirement can be combined in the same bank.

   Compatible example:

   SSTL15_I and LVDCI_15 outputs

   Incompatible example:

   SSTL15 (output V_CCO = 1.5V) and LVCMOS18 (output V_CCO = 1.8V) outputs

   Only one true differential output I/O standard can be used in HP I/O banks. LVDS with LVDS_PRE_EMPHASIS = FALSE (default) and LVDS with LVDS_PRE_EMPHASIS = TRUE are considered as two different true-differential output standards and cannot be combined within the same HP I/O bank.

2. Combining input standards only. Input standards with the same V_CCO and V_REF requirements can be combined in the same bank.

   Compatible example:

   LVCMOS15 and HSTL_I inputs

   Incompatible example:

   LVCMOS15 (input V_CCO = 1.5V) and LVCMOS18 (input V_CCO = 1.8V) inputs

   Incompatible example:

   HSTL_I_DCI_18 (VREF = 0.9V) and HSTL_I_DCI (VREF = 0.75V) inputs

3. Combining input standards and output standards. Input standards and output standards with the same V_CCO requirement can be combined in the same bank.

   Compatible example:

   LVDS_25 input and LVCMOS25 output

   Incompatible example:

   LVCMOS18 output (output V_CCO = 1.8 V) and HSTL_I output (input V_CCO = 1.5 V)

4. Combining bidirectional standards with input or output standards. When combining bidirectional I/O with other standards, make sure the bidirectional standard can meet the first three rules.

The implementation tools enforce these design rules.

The following table summarizes the V_CCO and V_REF requirements for each supported I/O standard. For more detailed DC specifications, including the recommended operating ranges of the supplies for each supported I/O standard, see the Spartan UltraScale+ FPGA Data Sheet: DC and AC Switching Characteristics (DS930) .

The following table summarizes the DRIVE and SLEW attribute options, bidirectional buffer availability, and DCI termination type for each supported I/O standard.