enigma

Amount of DCMs

3 posts in this topic

Hi,

I would like to know how many DCMs can be added to the papilio, and can the DCMs always only drive global clock pins?

I want to generate a few clocks and not use a state machine to generate them.

Regards

Enigma

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Hello Enigma,

The Spartan 3E has 4 DCM's, and each DCM is able to do a:

-Divided clock

-Doubled clock

-Custom speed (FX) clock

DCM's need to be driven by a global clock, but the output of a DCM does not need to be a global clock. DCM's output can go to any pin of the FPGA, or to any internal logic.

Thanks!

Jack.

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Don't forget the phase shifted outputs :)

I currently use a single DCM to drive:

  • CLKX2 - 64MHz picoBlaze
  • CLK0 - 32MHz pixel counter
  • CLKDV2 - 16MHz Servo PWM
  • CLKFX - 24MHz camera, uart, i2c

Works like a charm :)

Don't forget when using multiple DCMs to link their Locked/Reset I/Os with Inverters for stability.

post-12751-13431627686515.jpg

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