Example at ...\ncs\v1.4.0\zephyr\samples\drivers\display does not work with SSD1306 wired directly to nRF9160DK

[craig.stephan]

When I program the nrf9160dk with the example, the code detects the SSD1306, but the display looks like:

The image is only using the middle half (16 rows) of the display that has 32 rows and 128 columns. 

And the left side of the image is a random set of pixels.

What can I do to get the example to give me text on the screen?

I am using the SSD1306 OLED at: https://www.amazon.com/Pieces-Display-Module-SSD1306-3-3V-5V/dp/B08CDN5PSJ/ref=sr_1_8?dchild=1&keywords=ssd1306&qid=1606702037&sr=8-8

Do I have to modify any of the files to target the nRF9160 instead of the nRF52 family?

[helsing]

Here is a working solution where the whole area is in use. The result is some characters shown on the display.

The sample code is attached:

cfb-ncs150-oled-128x32-91dk-17-03-21.zip

Setup:

nRF Connect SDK: v1.5.0.

DK: nRF9160 DK v1.0.0 (I have also had success with DK v0.9.0).

OLED: Noname 4-pin 128x32 with SSD1306 display driver.

The display is connected to the DK like this:

SDA - P0.30

SCL - P0.31

VCC - 5V-pin on the side of the DK

GND - GND on DK

This is shown In the image at the top(yellow and red are connected, green and black are connected).

Below follows step-by-step instructions showing how the above project is modified from the original 'cfb' sample. I have added a few extra details for completeness:

1. Take a fresh copy of the Character Frame Buffer sample, cfb(v1.5.0\zephyr\samples\display\cfb).

2. Open the prj.conf file in the cfb folder with your text editor and add the following lines:

CONFIG_I2C=y
CONFIG_SSD1306=y

If you prefer white characters on black background, not the opposite, add this line as well:

CONFIG_SSD1306_REVERSE_MODE=y

The complete prj.conf file will then look like this:

CONFIG_STDOUT_CONSOLE=y

CONFIG_HEAP_MEM_POOL_SIZE=16384

CONFIG_DISPLAY=y

CONFIG_LOG=y

CONFIG_CFB_LOG_LEVEL_DBG=y
CONFIG_CHARACTER_FRAMEBUFFER=y

#Add these for the SSD1306 OLED:
CONFIG_I2C=y
CONFIG_SSD1306=y

#Reverse colors:
CONFIG_SSD1306_REVERSE_MODE=y

3. Next, in the project folder, 'cfb', create a file called 'nrf9160dk_nrf9160ns.overlay'

4. Open the file and add the following:

&i2c2 { 
    compatible = "nordic,nrf-twim";
    status = "okay";
    sda-pin = <30>;
    scl-pin = <31>;
    clock-frequency = <I2C_BITRATE_FAST>;
    zephyr,concat-buf-size = <1024>;


        ssd1306@3c {
        compatible = "solomon,ssd1306fb";
        reg = <0x3c>;
        label = "SSD1306";
        width = <128>;
        height = <32>;
        segment-offset = <0>;
        page-offset = <0>;
        display-offset = <0>; 
        multiplex-ratio = <31>;
        segment-remap;
        com-invdir;
        com-sequential;
        prechargep = <0x22>; 
    };
};

I have not used any shields in this project.

5. Then open nRF Connect v3.6.1 -> Toolchain Manager -> 'Open IDE' next to nRF Connect SDK v1.5.0. and SES opens.

6. In SES, clikc File -> Open nRF Connect SDK Project...

7. Select your project folder. Under Board Name, select 'nrf9160dk_nrf9160ns',  check 'Clean Build Directory'.

8. Build -> Build and Run.

The display should now output the characters '012345'. The image is flashing rapidly, I am working on how to solve this.

Please let me know how things works or fails.

Best regards,

Håkon

[Tor Kaufmann]

Appreciate the work that went into this solution, kudos!

I have the modified example up and running however still dealing with the flashing image.

Did you find a solution for this?

Thanks.

BR 

 

[Tor Kaufmann]

A solution to the "flashing" or "flickering problem was found here: https://github.com/zephyrproject-rtos/zephyr/issues/25161

define

uint8_t display_height = 32; (for the 128x32 display)

and change the last while loop where the characters are printed to this:

while (1) {
        cfb_framebuffer_clear(dev, false);
        for (int i = 0; i < (display_height / font_height); i++) {
            if (cfb_print(dev,
                          "0123456789mMgj!\\\"§$%&/()=",
                          0, i * font_height)) {
                printf("Failed to print a string\n");
                continue;
            }
        }

        cfb_framebuffer_finalize(dev);
        #if defined(CONFIG_ARCH_POSIX)
			k_sleep(K_MSEC(100));
        #endif
}

[helsing]

Hi Tor,

Thank you for sharing. I will include this when posting a short guide on how to get up and running with these oled displays.

As mentioned in the link, the display sample 'lvgl' is worth having a look at. When setting up that sample it is required(or highly recommended) to use the SSD1306 shield:

Add set(SHIELD ssd1306_128x32)after cmake_minimum_required(VERSION 3.13.1) in your CMakeLists.txt file of the lvgl sample. You might also need some configs.

Please create a new ticket if you need any more instructions.

Best regards,

Håkon