def run_simulation(self, period, load, slew):
""" This tries to simulate a period and checks if the result
works. If so, it returns True and the delays and slews."""
# Checking from not data_value to data_value
self.write_stimulus(period, load, slew)
stimuli.run_sim()
delay0 = ch.convert_to_float(ch.parse_output("timing", "delay0"))
delay1 = ch.convert_to_float(ch.parse_output("timing", "delay1"))
slew0 = ch.convert_to_float(ch.parse_output("timing", "slew0"))
slew1 = ch.convert_to_float(ch.parse_output("timing", "slew1"))
# if it failed or the read was longer than a period
if type(delay0) != float or type(delay1) != float or type(
slew1) != float or type(slew0) != float:
return (False, 0, 0, 0, 0)
delay0 *= 1e9
delay1 *= 1e9
slew0 *= 1e9
slew1 *= 1e9
if delay0 > period or delay1 > period or slew0 > period or slew1 > period:
return (False, 0, 0, 0, 0)
else:
debug.info(
2,
"Successful simulation: period {0} load {1} slew {2}, delay0={3}n delay1={4}ns slew0={5}n slew1={6}n"
.format(period, load, slew, delay0, delay1, slew0, slew1))
#key=raw_input("press return to continue")
# The delay is from the negative edge for our SRAM
return (True, delay1, slew1, delay0, slew0)
def try_period(self, period, load, slew, feasible_delay1, feasible_delay0):
""" This tries to simulate a period and checks if the result
works. If it does and the delay is within 5% still, it returns True."""
# Checking from not data_value to data_value
self.write_stimulus(period,load,slew)
stimuli.run_sim()
delay0 = ch.convert_to_float(ch.parse_output("timing", "delay0"))
delay1 = ch.convert_to_float(ch.parse_output("timing", "delay1"))
slew0 = ch.convert_to_float(ch.parse_output("timing", "slew0"))
slew1 = ch.convert_to_float(ch.parse_output("timing", "slew1"))
# if it failed or the read was longer than a period
if type(delay0)!=float or type(delay1)!=float or type(slew1)!=float or type(slew0)!=float:
debug.info(2,"Invalid measures: Period {0}, delay0={1}ns, delay1={2}ns slew0={3}ns slew1={4}ns".format(period, delay0, delay1, slew0, slew1))
return False
delay0 *= 1e9
delay1 *= 1e9
slew0 *= 1e9
slew1 *= 1e9
if delay0>period or delay1>period or slew0>period or slew1>period:
debug.info(2,"Too long delay/slew: Period {0}, delay0={1}ns, delay1={2}ns slew0={3}ns slew1={4}ns".format(period, delay0, delay1, slew0, slew1))
return False
else:
if not ch.relative_compare(delay1,feasible_delay1,error_tolerance=0.05):
debug.info(2,"Delay too big {0} vs {1}".format(delay1,feasible_delay1))
return False
elif not ch.relative_compare(delay0,feasible_delay0,error_tolerance=0.05):
debug.info(2,"Delay too big {0} vs {1}".format(delay0,feasible_delay0))
return False
#key=raw_input("press return to continue")
debug.info(2,"Successful period {0}, delay0={1}ns, delay1={2}ns slew0={3}ns slew1={4}ns".format(period, delay0, delay1, slew0, slew1))
return True
def try_period(self, period, load, slew, feasible_delay1, feasible_delay0):
""" This tries to simulate a period and checks if the result
works. If it does and the delay is within 5% still, it returns True."""
# Checking from not data_value to data_value
self.write_stimulus(period,load,slew)
stimuli.run_sim()
delay0 = ch.convert_to_float(ch.parse_output("timing", "delay0"))
delay1 = ch.convert_to_float(ch.parse_output("timing", "delay1"))
if type(delay0)==float:
delay0 *= 1e9
if type(delay1)==float:
delay1 *= 1e9
debug.info(2,"Period {0}, delay0={1}ns, delay1={2}ns".format(period,delay0, delay1))
# if it failed or the read was longer than a period
if type(delay0)!=float or type(delay1)!=float:
return False
else:
if ch.relative_compare(delay1*1e9,feasible_delay1,error_tolerance=0.05):
return False
elif ch.relative_compare(delay0*1e9,feasible_delay0,error_tolerance=0.05):
return False
#key=raw_input("press return to continue")
return True
def try_period(self, feasible_period, target_period, data_value):
""" This tries to simulate a period and checks if the result
works. If so, it returns True. If not, it it doubles the
period and returns False."""
# Checking from not data_value to data_value
self.write_stimulus(feasible_period, target_period, data_value)
stimuli.run_sim()
delay_value = ch.convert_to_float(ch.parse_output("timing", "delay"))
# if it failed or the read was longer than a period
if type(delay_value)!=float or delay_value*1e9>target_period:
debug.info(2,"Infeasible period " + str(target_period) + " delay " + str(delay_value*1e9) + "ns")
return (False, "NA")
else:
debug.info(2,"Feasible period " + str(feasible_period) \
+ ", target period " + str(target_period) \
+ ", read/write of " + str(data_value) \
+ ", delay=" + str(delay_value*1e9) + "ns")
#key=raw_input("press return to continue")
return (True, delay_value*1e9)
def bidir_search(self, correct_value, mode):
""" This will perform a bidirectional search for either setup or hold times.
It starts with the feasible priod and looks a half period beyond or before it
depending on whether we are doing setup or hold.
"""
# NOTE: The feasible bound is always feasible. This is why they are different for setup and hold.
# The clock will always be offset by 2*period from the start, so we want to look before and after
# this time. They are also unbalanced so that the average won't be right on the clock edge in the
# first iteration.
if mode == "SETUP":
feasible_bound = 1.25*self.period
infeasible_bound = 2.5*self.period
else:
infeasible_bound = 1.5*self.period
feasible_bound = 2.75*self.period
# Initial check if reference feasible bound time passes for correct_value, if not, we can't start the search!
self.write_stimulus(mode=mode,
target_time=feasible_bound,
correct_value=correct_value)
stimuli.run_sim()
ideal_clk_to_q = ch.convert_to_float(ch.parse_output("timing", "clk2q_delay"))
setuphold_time = ch.convert_to_float(ch.parse_output("timing", "setup_hold_time"))
debug.info(2,"*** {0} CHECK: {1} Ideal Clk-to-Q: {2} Setup/Hold: {3}".format(mode, correct_value,ideal_clk_to_q,setuphold_time))
if type(ideal_clk_to_q)!=float or type(setuphold_time)!=float:
debug.error("Initial hold time fails for data value feasible bound {0} Clk-to-Q {1} Setup/Hold {2}".format(feasible_bound,ideal_clk_to_q,setuphold_time),2)
if mode == "SETUP": # SETUP is clk-din, not din-clk
setuphold_time *= -1e9
else:
setuphold_time *= 1e9
passing_setuphold_time = setuphold_time
debug.info(2,"Checked initial {0} time {1}, data at {2}, clock at {3} ".format(mode,
setuphold_time,
feasible_bound,
2*self.period))
#raw_input("Press Enter to continue...")
while True:
target_time = (feasible_bound + infeasible_bound)/2
self.write_stimulus(mode=mode,
target_time=target_time,
correct_value=correct_value)
debug.info(2,"{0} value: {1} Target time: {2} Infeasible: {3} Feasible: {4}".format(mode,
correct_value,
target_time,
infeasible_bound,
feasible_bound))
stimuli.run_sim()
clk_to_q = ch.convert_to_float(ch.parse_output("timing", "clk2q_delay"))
setuphold_time = ch.convert_to_float(ch.parse_output("timing", "setup_hold_time"))
if type(clk_to_q)==float and (clk_to_q<1.1*ideal_clk_to_q) and type(setuphold_time)==float:
if mode == "SETUP": # SETUP is clk-din, not din-clk
setuphold_time *= -1e9
else:
setuphold_time *= 1e9
debug.info(2,"PASS Clk-to-Q: {0} Setup/Hold: {1}".format(clk_to_q,setuphold_time))
passing_setuphold_time = setuphold_time
feasible_bound = target_time
else:
debug.info(2,"FAIL Clk-to-Q: {0} Setup/Hold: {1}".format(clk_to_q,setuphold_time))
infeasible_bound = target_time
#raw_input("Press Enter to continue...")
if ch.relative_compare(feasible_bound, infeasible_bound, error_tolerance=0.001):
debug.info(3,"CONVERGE {0} vs {1}".format(feasible_bound,infeasible_bound))
break
debug.info(2,"Converged on {0} time {1}.".format(mode,passing_setuphold_time))
return passing_setuphold_time
def bidir_search(self, correct_value, noise_margin, measure_name, mode):
""" This will perform a bidirectional search for either setup or hold times.
It starts with the feasible priod and looks a half period beyond or before it
depending on whether we are doing setup or hold.
"""
period = tech.spice["feasible_period"]
# The clock will start being offset by a period, so we want to look before and after
# theis time.
if mode == "HOLD":
target_time = 1.5 * period
lower_bound = 0.5 * period
upper_bound = 1.5 * period
else:
target_time = 0.5 * period
lower_bound = 0.5 * period
upper_bound = 1.5 * period
previous_time = target_time
# Initial Check if reference setup time passes for correct_value
self.write_stimulus(mode=mode,
target_time=target_time,
correct_value=correct_value,
period=period,
noise_margin=noise_margin)
stimuli.run_sim()
output_value = ch.convert_to_float(
ch.parse_output("timing", measure_name))
debug.info(
3,
"Correct: {0} Output: {1} NM: {2}".format(correct_value,
output_value,
noise_margin))
if mode == "HOLD":
setuphold_time = target_time - period
else:
setuphold_time = period - target_time
debug.info(
3, "Target time: {0} Low: {1} Up: {2} Measured: {3}".format(
target_time, lower_bound, upper_bound, setuphold_time))
if not self.pass_fail_test(output_value, correct_value, noise_margin):
debug.error("Initial period/target hold time fails for data value",
2)
# We already found it feasible, so advance one step first thing.
if mode == "HOLD":
target_time -= 0.5 * (upper_bound - lower_bound)
else:
target_time += 0.5 * (upper_bound - lower_bound)
while True:
self.write_stimulus(mode=mode,
target_time=target_time,
correct_value=correct_value,
period=period,
noise_margin=noise_margin)
if mode == "HOLD":
setuphold_time = target_time - period
else:
setuphold_time = period - target_time
debug.info(
3, "Target time: {0} Low: {1} Up: {2} Measured: {3}".format(
target_time, lower_bound, upper_bound, setuphold_time))
stimuli.run_sim()
output_value = ch.convert_to_float(
ch.parse_output("timing", measure_name))
debug.info(
3, "Correct: {0} Output: {1} NM: {2}".format(
correct_value, output_value, noise_margin))
if self.pass_fail_test(output_value, correct_value, noise_margin):
debug.info(3, "PASS")
if ch.relative_compare(target_time, previous_time):
debug.info(
3, "CONVERGE " + str(target_time) + " " +
str(previous_time))
break
previous_time = target_time
if mode == "HOLD":
upper_bound = target_time
target_time -= 0.5 * (upper_bound - lower_bound)
else:
lower_bound = target_time
target_time += 0.5 * (upper_bound - lower_bound)
else:
debug.info(3, "FAIL")
if mode == "HOLD":
lower_bound = target_time
target_time += 0.5 * (upper_bound - lower_bound)
else:
upper_bound = target_time
target_time -= 0.5 * (upper_bound - lower_bound)
#raw_input("Press Enter to continue...")
# the clock starts offset by one clock period,
# so we always measure our setup or hold relative to this time
if mode == "HOLD":
setuphold_time = target_time - period
else:
setuphold_time = period - target_time
return setuphold_time