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Altera_Forum
Honored Contributor
9 years agoLights are turning on...I'm getting closer! Hopefully this ascii art prints properly...
# launch edge
# |
# |
# V
# ________________ ________________
# Launch CLK ______| |______________| |_____________
# ^ ^
# t=0.0 t=10.0
#
# _______________
# Data XXXXXXXX___V_A_L_I_D___XXXXXXXXXXXXXXXX
# ^ ^
# t=1.0 t=3.0
#
# latch edge
# |
# |
# V
# ________________ ________________
# Latch Clk _______| |______________| |_____________
# ^ ^
# t=-10.0 t=0.0
# ^
# _______________ |
# Data XXXXXXXX___V_A_L_I_D___XXXXXXXXXXXXXXX|
# ^ ^ |
# t=-9.0 t=-7.0 |
# |
# <--------max(+)---------------|
# <----min(+)----|
#
# max/min arrows point to positive value convention
#
# set_output_delay -max 9
# set_output_delay -min 7
#
#
#
# Alternative
#
# launched here latched here
# | |
# | |
# V V
# ________________ ________________
# Latch Clk _______| |______________| |_____________
# ^ ^
# t=-10.0 t=0.0
# ^
# | _______________
# Data XXXXXXXX??????????xxxxxxxxxxxxxxxxxxxx|xxx___V_A_L_I_D___xxxxxxxxxx
# | ^ ^
# | t=1.0 t=3.0
# |
# |---> max(-)
# |-----min(-)------>
#
# set_output_delay -max -1
# set_output_delay -min -3 I'm not sure I get the difference between method 1 and method 2. They are essentially defining the same setup and hold times, just at different points. Would the 2nd version indicate that when I launch the output data, it would take an extra clock cycle before being latched compared with 1st version?