Infer differential pairs, typically for ports just imported from a CSV or XDC file
Syntax
infer_diff_pairs [‑file_type <arg>] [‑quiet] [‑verbose] [<file>...]
Usage
Name | Description |
---|---|
[-file_type]
|
Input file type: 'csv' or 'xdc' Default: file type |
[-quiet]
|
Ignore command errors |
[-verbose]
|
Suspend message limits during command execution |
[<file>]
|
Pin Planning CSV or XDC file Default: file |
Categories
Description
The infer_diff_pairs
command can be used in an I/O Pin Planning project, after importing the I/O pin information using the read_csv
or read_xdc
command.
There are several attributes that identify differential pairs in the file: Signal Name, DiffPair Signal, DiffPair Type, and I/O Standard.
The tool will identify differential pairs using the following methods:
- Matching Diff Pair - This is a direct definition of the two signals which make up a differential pair. Two port entries, each have DiffPair Signal values linking to the Signal Name of the other, and have complementary DiffPair Type values, one N and one P. The tool checks to ensure that the other attributes such as I/O Standard are compatible when forming the diff pair.
- Unmatched Diff Pair - Two port entries, with complementary DiffPair Type values (one N, one P), but only one port has a DiffPair Signal linking to the other Signal Name. The tool will create the differential pair if all other attributes are compatible.
- Single Port Diff Pair - A single port entry with a differential I/O Standard, a DiffPair Type value, and a DiffPair Signal that does not otherwise appear in the CSV. The tool will create the opposite side of the differential pair (the N or P side), with all properties matching those on the original port.
- Inferred Diff Pair - Two ports entries, with Signal Names that imply the N and P side. The tool will infer a differential pair if all other attributes are compatible.
After reading the port definitions from a CSV or XDC file, the tool will report that some differential pairs can be inferred from the data. You can run the infer_diff_pairs
command to infer these differential pairs if you choose.
Arguments
-file_type [ csv | xdc ]
- (Optional) Specify the type of file to import when inferring differential pairs. The valid file types are CSV and XDC. There is no default; the -file_type
must be specified.
-quiet
- (Optional) Execute the command quietly, returning no messages from the command. The command also returns TCL_OK regardless of any errors encountered during execution.
-verbose
- (Optional) Temporarily override any message limits and return all messages from this command.
set_msg_config
command.Examples
read_xdc C:/Vivado_Install/io_1.xdc
infer_diff_pairs C:/Vivado_Install/io_1.xdc -file_type xdc