LEDs on OMAPL137/C6747 EVM

Bogdan15639

Intellectual 350 points

Dear All,

I would like to control the user LEDs and DIP switches from my application running in Linux on the ARM926 (OMAPL137).

Which header files should I include in my application? Is there any example available?

Many thanks,

Bogdan

over 15 years ago

0 Sekhar Nori over 15 years ago

TI__Expert 6385 points

Hi Bogdan,

Assuming that these are interfaced using GPIO, you can have a look at the GPIO example included the in PSP package in src/examples/gpio.

http://software-dl.ti.com/dsps/dsps_public_sw/psp/LinuxPSP/DaVinci_03_20/index.html

Thanks,

Sekhar

0 Bogdan15639 over 15 years ago in reply to Sekhar Nori

Intellectual 350 points

Hi Sekhar,

Thanks for the reply! The example creates a module. Is there any way to do the same thing without writing a kernel module i.e. to modify the OMAPL137 registers directly from my application?

Bogdan

0 Sekhar Nori over 15 years ago in reply to Bogdan15639

TI__Expert 6385 points

Hi Bogdan,

The Linux kernel does not have a direct user space interface to GPIOs.

You should implement an LED/Switch driver providing a user space interface and utilizing the GPIO library present in the kernel.

You could probably manipulate the GPIO registers directly from userspace by using a tool like devmem2, but that would not be advised because you could end up in a race with the kernel side GPIO driver.

Thanks,

Sekhar

0 Bogdan15639 over 15 years ago in reply to Sekhar Nori

Intellectual 350 points

I also thought so...many thanks for the answers!

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LEDs on OMAPL137/C6747 EVM