Timing Functions

The most frequently used timing delay functions. Some are also available on the

various clock interfaces, but these standalone versions are decoupled here

for more lightweight, streamlined inline requirements. For accurate and precise

timing only delay(…) and delayMicros(…) are recommended. The other

versions are for testing and comparative purposes only.

delay(delay_time)

Initiates a delay for the specified amount of time in milliseconds The underlying timing mechanism uses the most accurate, valid monotonic time available. Monotonic time moves unidirectionally forward and runs independently of the variations that occur with a system clock. This delay function can be used safely inside a process thread. It is named after the Arduino delay function.

Parameters

delay_time – amount of time to delay (milliseconds)

Returns

None

Example

Variations on 1 second delays with with different delay times

and 2 forms of output for uptime

Shows the accuracy of the delay(…) function

from robotime.time import delay
from robotime.clocks import Clock

c = Clock()

for i in range(5):
    print(c.getUptimeStr())
    delay(1000)

print()
delay(1000) # wait 1 sec

for i in range(5):
    print(c.getUptimeStr())
    delay(1000)

print()
c.delay(1000) # use delay on Clock() interface

c.uptime()

for i in range(2):
 for j in range(10): # same as delay(1000)
      delay(100)
 c.uptime()
 delay(1000) # same delay as j loop
 c.uptime()

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delayMicros(delay_time)

Initiates a delay for the specified amount of time in microseconds The underlying timing mechanism uses the most accurate, valid monotonic time available. This delay function can be used safely inside a process thread.

Parameters

delay_time – amount of time to delay (microseconds)

Returns

None

Example

from robotime.time import delayMicros
from robotime.clocks import Clock

c = Clock()

for i in range(5):
    print(c.getUptimeStr())
    delayMicros(1000000) # 1 second

00:00:00
00:00:01
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00:00:04

delaySp(delay_time)

Initiates a delay for the specified amount of time in microseconds This is a time.sleep() based version of delay. Included here for comparison testing or other applications. Never as accurate as monotime based delay.

Parameters

delay_time – amount of time to delay (microseconds)

Returns

None

delayTc(delay_time)

Initiates a delay for the specified amount of time in microseconds This is a time.clock() based version of delay. Included here for comparison testing or other applications. Never as accurate as monotime based delay.

Parameters

delay_time – amount of time to delay (microseconds)

Returns

None

delayTm(delay_time):

Initiates a delay for the specified amount of time in microseconds. This is a time.time() based version of delay. Included here only for comparison testing. The timing delay mechanism can skew forward or backward in time depending on the underlying OS (HW/SW) system clock and its adjustments for regions, time zones and other geographic related parameters. Or abruptly jump or change time if the system clock is set or reset. Never as accurate as monotime based delay.

Parameters

delay_time – amount of time to delay (microseconds)

Returns

None