I have the sample constraint file for my Arty board. I notice that where it says a clock signal is created in the file, it specifies a specific port that the clock is found on, specifically PACKAGE_PIN E3.
This creates a 100 MHz clock for the Arty. However, my current project needs a 20 MHz clock.
I lack the FPGA knowledge to know whether these two lines of code are *describing* a clock that already exists at E3 on the Verilog board, or *creating* it. The "create clock" implies that it's creating, but the way the rest of the constraint file is formatted - with a list of the pins that exist on the Arty and their locations - suggests that it's only describing.
Is it safe or even possible to make a 20 MHz clock by simply changing the number after -period to 50.00 for a 50 ns 20 MHz clock? Is there a way I can also keep the 100 MHz clock at the same time?
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wanderso
I have the sample constraint file for my Arty board. I notice that where it says a clock signal is created in the file, it specifies a specific port that the clock is found on, specifically PACKAGE_PIN E3.
set_property -dict { PACKAGE_PIN E3 IOSTANDARD LVCMOS33 } [get_ports { CLK100MHZ }]; #IO_L12P_T1_MRCC_35 Sch=gclk[100]
create_clock -add -name sys_clk_pin -period 10.00 -waveform {0 5} [get_ports {CLK100MHZ}];
This creates a 100 MHz clock for the Arty. However, my current project needs a 20 MHz clock.
I lack the FPGA knowledge to know whether these two lines of code are *describing* a clock that already exists at E3 on the Verilog board, or *creating* it. The "create clock" implies that it's creating, but the way the rest of the constraint file is formatted - with a list of the pins that exist on the Arty and their locations - suggests that it's only describing.
Is it safe or even possible to make a 20 MHz clock by simply changing the number after -period to 50.00 for a 50 ns 20 MHz clock? Is there a way I can also keep the 100 MHz clock at the same time?
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