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Very simple question

marc murphy
Intellectual 560 points
Hopefuly someone out there has the information about this. What is the fastest realistic duty cycle that can be expected for a GPIO interrupt using Linux and assigning the gpio to an irq ? Currently the fastest I can achieve is 10ms but I need to get it to around 1ms. I find it hard to believe a ucontroller running at 800MHz can only achieve 10ms. If there is anyone that can give pointers as to how I can establish that the pinmux and the registers are set correctly it wold greatly assist the project. Thanks in advance Marc
  • 0
    Guru 31670 points

    Marc,

    I believe you should be able to achieve less than 10ms in Linux. I'm not exactly sure, but could you please try these?

    1. Check in kernel config whether CONFIG_NO_HZ=y is set. If so, disable it in menuconfig, so that the system will become tick-based and earlier it was configured as tickless. 

    2. See the value of CONFIG_HZ. By default it might be 100. Try to make it 1000. To do this directly editing the .config file might not be enough, you might have to go and edit arch/arm/Kconfig.

    -Renjith

    www.pathpartnertech.com