polling-frequency of I/O-port

[ahf...@gmail.com]

hello to every one,here is Yangyang.I want to know,how can test the polling-frequency of I/O-port on beaglebone black,and what is the maximum speed of the frequency ? The max. speed what I test is around 27kHz. Hope there is anyone can help me

contact via ahf...@gmail.com. Thanks.

Here is my code(python):

from bbio import *

import time

testIO = GPIO1_28    #P9_12

testVar = 0 

counter  = 0

cntMax = 10000

startTiME = time.time()

endTiME = 0

pinMode(testIO, INPUT)

while 1:

    if counter >= cntMax:

        endTiME = time.time()

        print 'Frequenz an test IO:', cntMax / (endTiME - startTiME)

        counter = 0

        startTiME = time.time()

    else:

        if not digitalRead(testIO) == testVar:

            testVar = not testVar

            counter += 1

[William Hermans]

A few things about your code.

First, if you're concerned about performance, you're using the wrong language. Wrong type of a language for that matter. You should be using C, C++, or ASM. *IF* you're concerned about performance.

Secondly, calling a time() related function in your main loop, every iteration will slow your code down.

Thirdly printing to stdout every iteration of your loop will slow your application down A LOT.

Lastly, I'm not sure if the bbio library uses sysfs for manipulating pins or not. But if it does. There are performance limitations associated with this as well. 

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