Setting DCM Frequency Aligned Mode
To set the DCM into the frequency aligned mode of operation a special option must be used during configuration file generation. This can be set in the ISE tools as shown in these screen shots from an ISE v8.1i project for this reference design.
Hint – The format of this special DCM option are described in some detail in the ‘frequency_generator.vhd’ file from which you can also copy and paste to avoid typing errors!
1)In the ‘Processes’ window select ‘Generate Programming File’. Then right click and select ‘Properties’ to open the ‘Process Properties’ box.
2)The ‘Process Properties’ box should open with the ‘General Options’ being shown (otherwise select ‘General Options’ on the left). Move to the line ‘Other Bitgen Command Line Options’ and enter the text string shown below.
Hint – You may need to set ‘Property display level’ to ‘Advanced’ and scroll down to see this line.
3) Select ‘Apply’ and then use ‘OK’ to exit the box.
Hint – Reopen the box and confirm the option really was set correctly.
Frequency Generator for the
