If am running a simulation in modelsim an there is a DCM block with a locked signal. Now because correct me if I am wrong but I would need to stimulate the locked signal myself because the DCM will not set it as this is just a simulation and the DCM is a piece of hardware. Hope that makes sense? Thanks Jon
Spartan 3 DCM
Started by ●March 14, 2006
Reply by ●March 14, 20062006-03-14
maxascent wrote:> If am running a simulation in modelsim an there is a DCM block with a > locked signal. Now because correct me if I am wrong but I would need to > stimulate the locked signal myself because the DCM will not set it as this > is just a simulation and the DCM is a piece of hardware. Hope that makes > sense?The DCM model does generate the locked signal. Cheers, Jon
Reply by ●March 14, 20062006-03-14
I would be very careful of using the "locked" signal in any Spartan-3 based design as it does not always behave in the way that people assume. John Adair Enterpoint Ltd. - Home of Broaddown2. The Ultimate Spartan-3 Development Board. http://www.enterpoint.co.uk "maxascent" <maxascent@yahoo.co.uk> wrote in message news:sMmdnUj9krw4IYvZRVn_vA@giganews.com...> If am running a simulation in modelsim an there is a DCM block with a > locked signal. Now because correct me if I am wrong but I would need to > stimulate the locked signal myself because the DCM will not set it as this > is just a simulation and the DCM is a piece of hardware. Hope that makes > sense? > > Thanks > > Jon
Reply by ●March 14, 20062006-03-14
I have a DDR design from Xilinx MIG and the lock signal never moves from '0'. So I have just created my own design with just a DCM and the lock signal still is '0'. I cant see that I am doing anything particularly wrong? Cheers Jon
Reply by ●March 15, 20062006-03-15
maxascent wrote:> I have a DDR design from Xilinx MIG and the lock signal never moves from > '0'. So I have just created my own design with just a DCM and the lock > signal still is '0'. I cant see that I am doing anything particularly > wrong? > > Cheers > > JonAre you resetting the DCM (after at least 16 clocks) ? is your input clock at least 25 MHz? did you set the resolution of the simulator at 1ps? Francesco
Reply by ●March 15, 20062006-03-15