better sleep management to slow down clocking as required

src/ttboard/cocotb/time/system.py

@@ -6,9 +6,11 @@
 '''
 from ttboard.cocotb.time.value import TimeValue
 from ttboard.cocotb.clock import Clock
+import ttboard.util.time as time 
 
 class SystemTime:
     _global_time = TimeValue(0, 'ns')
+    _min_sleep_time = TimeValue(10, 'us')
 
     @classmethod 
     def reset(cls):
@@ -25,12 +27,17 @@ def set_units(cls, units:str):
     @classmethod 
     def advance(cls, time_or_timevalue, units:str=None):
         if isinstance(time_or_timevalue, TimeValue):
-            cls._global_time += time_or_timevalue
+            tstep = time_or_timevalue
         elif isinstance(time_or_timevalue, int) and units is not None:
-            cls._global_time += TimeValue(time_or_timevalue, units)
+            tstep = TimeValue(time_or_timevalue, units)
         else:
             raise ValueError
 
+        cls._global_time += tstep
+        if cls._min_sleep_time < tstep:
+            time.sleep_us(tstep.time_in('us'))
+
+
         for clk in Clock.all():
             clk.time_is_now(cls._global_time)
 

src/ttboard/cocotb/time/value.py

@@ -96,6 +96,9 @@ def __lt__(self, other):
     def __le__(self, other):
         return not (self > other)
 
+    def __ge__(self, other):
+        return float(self) >= float(other)
+
     def __eq__(self, other):
         return float(self) == float(other)
 

src/ttboard/cocotb/triggers/timer.py

@@ -21,7 +21,6 @@ def run_timer(self):
         # print(f"All clocks on timer: {all_clocks}")
         fastest_clock = all_clocks[0]
         time_increment = fastest_clock.half_period
-        sleep_us = fastest_clock.sleep_us
         target_time = SystemTime.current() + self.time
         increment_count = 0
         while SystemTime.current() < target_time:
@@ -31,8 +30,6 @@ def run_timer(self):
             increment_count += 1
             SystemTime.advance(time_increment)
 
-            if sleep_us > 0:
-                tm.sleep_us(sleep_us)
 
     def __iter__(self):
         return self