Python 2.7.9 (default, Sep 17 2016, 20:26:04) 
[GCC 4.9.2] on linux2
Type "copyright", "credits" or "license()" for more information.
>>> from a_star import AStar
>>> import time
>>> a = AStar()
>>> tSteps = [.1, .05, .025, .0125, .00625]
>>> for step in tSteps:
	print step
	t0 = time.time()
	while time.time() - t0 < 60:
	    a.test_read8()
	    time.sleep(step)

		
0.1
0.05
0.025
0.0125
0.00625
>>> for step in tSteps:
	print step
	t0 = time.time()
	while time.time() - t0 < 60:
	    analog = a.read_analog()
	    time.sleep(step)

		
0.1
0.05
0.025
0.0125
0.00625
>>> for step in tSteps:
	print step
	t0 = time.time()
	while time.time() - t0 < 60:
	    a.test_write8()
	    time.sleep(step)

		
0.1
0.05
0.025
0.0125
0.00625
>>> for step in tSteps:
	print step
	t0 = time.time()
	while time.time() - t0 < 60:
	    analog = a.read_analog()
	    a.motors(0, 0)
	    time.sleep(step)

		
0.1
0.05

Traceback (most recent call last):
  File "<pyshell#20>", line 5, in <module>
    analog = a.read_analog()
  File "a_star.py", line 43, in read_analog
    return self.read_unpack(12, 12, "HHHHHH")
  File "a_star.py", line 20, in read_unpack
    byte_list.append(self.bus.read_byte(20))
IOError: [Errno 5] Input/output error
>>> 
>>> for step in tSteps:
	print step
	t0 = time.time()
	while time.time() - t0 < 60:
	    analog = a.read_analog()
	    a.motors(0, 0)
	    time.sleep(step)

		
0.1
0.05
0.025
0.0125
0.00625

Traceback (most recent call last):
  File "<pyshell#23>", line 5, in <module>
    analog = a.read_analog()
  File "a_star.py", line 43, in read_analog
    return self.read_unpack(12, 12, "HHHHHH")
  File "a_star.py", line 20, in read_unpack
    byte_list.append(self.bus.read_byte(20))
IOError: [Errno 5] Input/output error
>>> for step in tSteps:
	print step
	t0 = time.time()
	while time.time() - t0 < 60:
	    analog = a.read_analog()
	    a.motors(0, 0)
	    time.sleep(step)

		
0.1
0.05
0.025
0.0125
0.00625
>>> step = .00625
>>> while True:
	print step
	t0 = time.time()
	while time.time() - t0 < 60:
	    a.test_write8()
	    time.sleep(step)
	step /= 2

	
0.00625
0.003125
0.0015625
0.00078125
0.000390625
0.0001953125
9.765625e-05
4.8828125e-05
2.44140625e-05

Traceback (most recent call last):
  File "<pyshell#12>", line 6, in <module>
    time.sleep(step)
KeyboardInterrupt
>>> for once in range(1): # To avoid delay between next two lines
	t0 = time.time()
	for i in range(500):
		a.test_write8()
	total_time = time.time() - t0

	
>>> 8 * 500 * 8 / total_time / 1000
130.68810369539477