pkg: u8glib: add initial support for graphics library

[basilfx]

This PR adds initial support for U8glib graphics library as an external package. While targeted for Arduino MCUs, it works fine on 32-bit MCUs. The license should be compatible (new-style BSD).

I've tested this with a cheap SSD1306 OLED display via SPI, but it also has a stdout (for native) and I2C backend (untested). The included test application cycles through three pages, each second. Several other displays are also supported.

The code size for the test application only (EFM32, STK3600, SPI) is approximately 4.0 kb.

[OlegHahm]

nice!

[OlegHahm]

Can you update this Makefile to use "git cache" from #5112, please?

[basilfx]

Added git-cache support and fixed some gcc errors (I normally use clang).

[aabadie]

Thanks for the PR ! That was something I was also thinking about.
I tested it yesterday with a samr21-xpro and the OLED1 Xplained extension. The extension uses SPI so, according to the datasheet, I adapted the test application using this SPI initialization call:

#define SPI_INTERFACE SPI_1
#define SS_PIN GPIO_PIN(PB,03)
#define A0_PIN GPIO_PIN(PA,13)
#define RS_PIN GPIO_PIN(PA,23)

int main(void)
{
    uint32_t screen = 0;
    u8g_t u8g; 
    u8g_spi_t dev;

    if (u8g_init_spi(&dev, SPI_INTERFACE, SS_PIN, A0_PIN, RS_PIN, &u8g, &u8g_dev_ssd1306_128x32_hw_spi)) {
        puts("Failed to initialize U8glib to SPI device.");
        return -1;
    }

/* draw text */
...

Unfortunately, nothing is displayed. I plan to test with another board asap (arduino-due for instance).

[basilfx]

Unfortunately, nothing is displayed. I plan to test with another board asap (arduino-due for instance).

Hmm, not sure what is wrong. You can try to swap SS/A0/RS pins and see if that makes a difference. This is because my cheap OLED display uses vague names, so I basically guessed and tried until it worked :-)

You can also try to set breakpoints in the u8g_com_riotos_hw_spi_fn method and see if the correct pins toggle.

Does the native/stdout backend work for you?

[OlegHahm]

I tested the native/stdout and it worked for me. Don't have any other hardware to test right now.

[basilfx]

Adapted to new pkg structure and rebased.

[basilfx]

I bought the same SSD1306 OLED display, but this time with an I2C interface. I have updated this PR so that both interfaces work.

(The test application only supports one display at a time, but the graphics memory survives a reboot/flash.)

[basilfx]

Fixed couple of things to make Murdock happy:

• Removed interface drivers from U8glib because of conflicts with the Arduino and MSP430 builds. These builds have their own defines (e.g. ARDUINO, __MSP430__) which would compile different code that would circumvent the RIOT-OS interface.
• Unified file names for RIOT-OS interface

Now Murdock is happy.

[kaspar030]

Is this the copyright you want to add? It's 2016. ;)

[kaspar030]

Please address copyright if needed, then squash.
We usually squash into one commit for the package, one for the test.

Very nice, I wish I had such a display!

[basilfx]

Changed the copyright and squashed into two separate commits.

[basilfx]

After #5435, this PR should build again.

[basilfx]

Don't merge this PR yet. I'm improving the interface to RIOT-OS, which depends on a PR I have submitted to U8glib. I hope that gets merged, otherwise I will point it to my own branch.

In the mean time, enjoy this picture of this PR running on a low-power memory display :-)

[basilfx]

I will close this PR as I am working on porting the successor of U8glib to RIOT-OS. The successor is (IMHO) much easier to use, includes the fixes I originally PR'd for U8glib and is less coupled to Arduino. It also need less patches.

I'll open a new PR once it is ready.

[miri64]

It would have been perfectly fine to just rework this PR, but no problem. Looking forward for the new PR :-).