Cyclone III PLL not locking after reconfig

Question

I'm using dynamic reconfiguration to change frequencies of a Cyclone PLL.

I'm using the ALTPLLRECONFIG and ALTPLL IPs.

When I load the new parameters and send configupdate I lose lock as expected but never regain lock.

Any ideas why this may occur?

Thanks,

Ed

altera_forum · Answer

im in a same situation. follow these links and tell me if you succeed.

find this example file

altpll_reconfig_ex1_msim.zip

also follow

please dont forget about me :) if you succeed share your information.

altera_forum · Answer

This can happen on stratix 3 FPGA when the re programmed frequency is too low (Like 5 MHz with an input of 20 MHz).

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