Question

我在Raspberry Pi上使用timer2时遇到了麻烦

这是代码

************************************************************** 
#  tmr2_tst_04.py
#  https://github.com/ask/timer2
#  http://pymotw.com/2/threading/index.html#thread-objects
# ISSUES:
#
#   *)  Seems to respond only to even seconds
#
#   *)  Is off by 1 second.  i.e.  4000 gives a 5 second interrupt

import timer2
import time       #  for sleep
import signal,sys

def signal_handler(signal, frame):
    print 'You pressed Ctrl+C!'
    timer.stop()
    sys.exit(0)

#time_to_wait = 4500
#time_to_wait = 4999
time_to_wait = 4000.0    #  gives 5-second cycle time !!!
#time_to_wait = 500.0     #  doesn't work

tm = 0
tdiff = 0
tm_old = -1
iter = 0
to_print = False

def hello():
    global iter
    global tm, tdiff
    global tm_old
    global to_print

    tm = time.time()
    tdiff = (tm - tm_old) if tm_old > 0  else  0
    tm_old = tm
    iter += 1


#   buf = "%3d %d %f %6.4f %s" % (iter, time_to_wait, tm, tdiff, "Hello world")
#   print buf
    to_print = True

#    Set up to catch ^C
signal.signal(signal.SIGINT, signal_handler)
print 'Press Ctrl+C to exit'

#   Set up timer interrupt routine
timer = timer2.Timer()
timer.apply_interval(time_to_wait, hello)



#  Main program loop
while iter <= 10000:
    if to_print:
        buf = "%3d %d %f %6.4f %s" % (iter, time_to_wait, tm, tdiff, "Hello world")
        print buf
        to_print = False
    time.sleep((time_to_wait/1000)/2)

timer.stop()

*************************************************************************

这在Raspberry Pi上每5000毫秒运行一个“hello”线程，但在UBUNTU机器上每4000毫秒运行

第二个问题 - 如果我尝试短时间间隔，请说

time_to_wait = 500

它完全不起作用 - 只需在时间差为.1毫秒的时间内完成代码！

Answer 1

它正在调用Python的sleep函数，该函数在几秒钟内获取参数。理想情况下，你所做的将把它转换为.25秒，但所涉及的所有数字都是整数。

作为整数，500/1000 = 0,0 / 2 = 0，依此类推。因此，它会在继续之前等待请求的0秒。例如，将1000更改为1000.0，它应该可以正常工作。

在Raspberry Pi上使用timer2的问题

1 个答案: