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Altera_Forum
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13 years ago

Very slow clock signals and STA in TimeQuest

For some specific usage, I need some very slow clock signals. They are generated from FPGA for outside chip. For example, the FPGA clock is 40Mhz, so clock period is 25ns and I named this cloc...
Altera_Forum's avatar
Altera_Forum
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13 years ago

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You use the create_generated_clock command

create_generated_clock -name slow_clock -source sys_clock -divide_by 256 [get_registers slow_clock_register]

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Just be careful with this. The -clock option cannot actually take the name of a clock as an argument. You can use -clock [get_ports clk_25ns] instead. Also, since your counter is composed of multiple registers, make sure you specify the actual bit you want the clock tied to, e.g. [get_registers slow_clock_register[7]], or even more specific [get_pins slow_clock_register[7]|q].