[GSOC] GPIO status and I2C start

Andre Marques andre.lousa.marques at gmail.com
Fri Jul 18 15:03:25 UTC 2014

Hello Alan

On 07/18/14 14:06, Alan Cudmore wrote:
> Hi André,
> I have a couple of SPI devices to try now. I have the SPI FRAM chip:
> https://www.adafruit.com/product/1897

I have here a similar device

Will try to test it with the PI this weekend.

I also have the following devices here:

(I2C) http://www.microchip.com/wwwproducts/Devices.aspx?product=MCP23008

(SPI)(I2C) http://www.newhavendisplay.com/nhd0216k3zflgbwv3-p-5738.html

> and something that could be interesting, an SPI based LCD/touchscreen:
> https://www.adafruit.com/products/1601

It does look interesting.

> I can also verify that the RTEMS BSP works fine on the new Raspberry 
> Pi Model B+

Nice. By the way, currently the BSP does not recognize (or I have missed 
it) which raspberry Pi version it is running on, and as new peripherals 
are added to the BSP it becomes important to have that info. For 
instance, the I2C interface on the P1 GPIO header uses different pin 
numbers for model A and model B/B+.

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