Altera Corporation
2–227
October 2007
Stratix II GX Device Handbook, Volume 2
Stratix II GX Transceiver Architecture Overview
Since the data arrival time is later than the data required time by 0.798 ns,
the maximum delay and minimum delay should both be incremented by
0.8 ns in the SDC file. The new SDC file should have the following
modified constraints for the
gxb_powerdown
port.
#***************************************************
# Set Maximum Delay
#****************************************************
set_max_delay -from [get_keepers
{reset_seq_tx_rx_rx_cruclk_rx_clkout:inst2|gxb_powerd
own}] -to [get_ports
{PIPE_DataGen_Ch:inst|alt2gxb:alt2gxb_component|chann
el_quad[0].cent_unit~OBSERVABLEQUADRESET}] 4.8
#****************************************************
# Set Minimum Delay
#****************************************************
set_min_delay -from [get_keepers
{reset_seq_tx_rx_rx_cruclk_rx_clkout:inst2|gxb_powerd
own}] -to [get_ports
{PIPE_DataGen_Ch:inst|alt2gxb:alt2gxb_component|chann
el_quad[0].cent_unit~OBSERVABLEQUADRESET}] 2.000
After modifying the SDC file and running the Quartus II Fitter, the
Update Timing Netlist
option should be executed, followed by
Report
Top Failing Paths
. If the
gxb_powerdown
port still shows in the failing
paths, modify the slack appropriately in the SDC file and repeat the
procedure until timing is met on this path.
Follow the same procedure to set timing constraints on all transceiver
reset/powerdown ports in your design.
1
You should set constraints and meet timing for both fast and
slow timing models. The same maximum and minimum delay
constraints might not be able to meet timing for both timing
models. This is acceptable as long as the skew is within the
specified period (2.8 ns) for each path in the SDC file for each
timing model.