Forum Discussion

XQSHEN's avatar
XQSHEN
Icon for Occasional Contributor rankOccasional Contributor
4 years ago
Solved

How to set timing constraint for JTAG

  • ak6dn's avatar
    4 years ago

    Here is how I put timing constraints on a JTAG interface (I do it in an .sdc constraint file):

    # JTAG setup for Altera USB Blaster
    
    set_false_path -from [get_ports {altera_reserved_*}] -to CPUCLK
    set_false_path -from CPUCLK -to [get_ports {altera_reserved_*}]
    
    create_clock -name altera_reserved_tck -period 40 {altera_reserved_tck}
    remove_input_delay [get_ports {altera_reserved_tdi altera_reserved_tms}]
    set_input_delay -clock altera_reserved_tck -clock_fall 3 [get_ports {altera_reserved_tdi altera_reserved_tms}]
    remove_output_delay [get_ports {altera_reserved_tdo}]
    set_output_delay -clock altera_reserved_tck 3 [get_ports {altera_reserved_tdo}]
    
    # Cut off paths between async clock domains
    
    remove_clock_groups -all
    set_clock_groups -asynchronous -group {CPUCLK} -group {altera_reserved_tck}