[GSOC] GPIO status and I2C start

Alan Cudmore alan.cudmore at gmail.com
Mon Jul 7 13:37:58 UTC 2014

Hi André,
I updated my Pi setup to add the second LED and switch, and your example
works for me. I did notice that when I power off the Rapberry Pi, then
power it back on, the second LED will remain lit and cause interrupts in
the RTEMS program. If I leave the Pi powered off for a little while, it
works as intended. I don't think this is an RTEMS problem. The good news is
that the RTEMS app continues to run and handle the interrupts, so it is

I will experiment with different button and LED combinations in the next
few days.

When you have an I2C driver to try, I have a number of I2C devices to
interface. I will have to find an SPI device to try out. Something like

A question about the examples ( maybe not for Andre ):
Can we keep Board/BSP specific tests in the testsuites/samples directory?


On Sat, Jul 5, 2014 at 6:58 PM, Andre Marques <andre.lousa.marques at gmail.com
> wrote:

> Hello,
> The Raspberry Pi GPIO interrupts are already working, and a test case is
> available to test that [1]. A function is also provided to debounce a
> switch if needed. The test case requires two switches and two LEDS using
> the same setup described at [2] by only changing the pin numbers.
> The test works by setting interrupts on both edges of the switches, which
> handlers will turn on or off the corresponding LED. One of the LEDs also
> has a level interrupt which prints a message on the screen when the LED is
> on (high level).
> While I wait for some feedback on that, I will be looking at the next
> step: the I2C interface. To test both the I2C and the SPI interfaces I have
> here a simple display [3]. The idea is to create a low level driver for I2C
> to provide the needed directives for the libi2c API, so the driver for the
> display will actually use the libi2c API. Any thoughts here are welcome too!
> Thanks,
> André Marques.
> [1] - https://github.com/asuol/rtems/blob/GPIO_API/
> testsuites/samples/LIBGPIO_TEST_IQR/init.c
> [2] - http://asuolgsoc2014.wordpress.com/2014/06/22/testing-the-gpio-api/
> [3] - http://www.newhavendisplay.com/nhd0216k3zflgbwv3-p-5738.html
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