DCM virtex 2 doesn't lose lock

  • Thread starter Bram van de Kerkhof
  • Start date
B

Bram van de Kerkhof

Guest
Hi,

I have a design that transmits data trough a cable and sends the clock
along. At the receiver side
the clock is going trough a dcm when i disconnect the cable the dcm doesn't
lose his lock (somtimes it does).
there is some rubbisch in the hanging cable (status bit is toggling)

what could be the problem. the rubbisch in the cable is not good enough to
filter a clock out of it. Even if
there is no rubbisch the lock doesn't dissapear (have measured it)

Yours Bram


--
==================================================
Bram van de Kerkhof

OCE-Technologies BV
Building 3N38

St. Urbanusweg 43,
Venlo, The Netherlands
P.O. Box 101, 5900 MA Venlo
==================================================
Direct dial : +31-77-359 2148
Fax : +31-77-359 5473
==================================================
e-mail : mailto:bvdk@oce.nl
==================================================
www : http://www.oce.nl/
==================================================
 
Bram,

The DCM is a synchronous state machine, and if the clock is lost, it does not
have the ability to change the LOCKED signal, but the CLKIN_LOST status bit
does go high.

I suggest you use the status bits more fully to determine the true state of the
DCM.

Austin

Bram van de Kerkhof wrote:

Hi,

I have a design that transmits data trough a cable and sends the clock
along. At the receiver side
the clock is going trough a dcm when i disconnect the cable the dcm doesn't
lose his lock (somtimes it does).
there is some rubbisch in the hanging cable (status bit is toggling)

what could be the problem. the rubbisch in the cable is not good enough to
filter a clock out of it. Even if
there is no rubbisch the lock doesn't dissapear (have measured it)

Yours Bram

--
==================================================
Bram van de Kerkhof

OCE-Technologies BV
Building 3N38

St. Urbanusweg 43,
Venlo, The Netherlands
P.O. Box 101, 5900 MA Venlo
==================================================
Direct dial : +31-77-359 2148
Fax : +31-77-359 5473
==================================================
e-mail : mailto:bvdk@oce.nl
==================================================
www : http://www.oce.nl/
==================================================
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