Answers Database
Leonardo: How to change the slew rate from Leonardo.(Fast, Nodelay)
Record #4244
Problem Title:
Leonardo: How to change the slew rate from Leonardo.(Fast, Nodelay)
Problem Description:
Urgency: Standard
General Description:
Leonardo currently defaults all outputs with the slew rate set
to FAST. The following describes how to change the slew rates
Solution 1:
Leonardo also default input register to NODELAY.
Here is how you can set a port with delay in Leonardo.
Say, the signal going from ibuf to IFD is called data_in.
After doing a 'READ' you can then do:
set_attribute -port data_in -name DELAY -value TRUE
Then do 'Optimize', 'WRITE', M1 etc.
Also you can specify the instance of the IFD if it is
instantiated, or also the net name.
set_attribute -instance my_ifd -name DELAY -value TRUE
or
set_attribute -net net_name -name DELAY -value TRUE.
You should also be able to specify the medium delay if needed
... MEDDELAY.
Solution 2:
To set an output port with a FAST slew rate:
set_attribute -port <portname> -name FAST
To set all other output ports with a SLOW slew rate:
set xlx_fast_slew FALSE
Internal Note: Using M1.4 with Leonardo 4.2, one can not
change the slew rate to slow via the ucf file
End of Record #4244 - Last Modified: 01/20/99 12:11 |
