e-paper: IL3829 kernel driver implementation for Zephir OS

Installation

1. Clone this repository
2. Connect driver as Zephyr external module in CMakelists.txt, example:

   set(CUSTOM_DRV_DIR $ENV{HOME}/workspace/zephyr)
   set(DRV_DISPLAY ${CUSTOM_DRV_DIR}/drivers/display/epaper_il3829)
   
   list(APPEND ZEPHYR_EXTRA_MODULES
   ${DRV_DISPLAY}
   )

3. Create or add to your device overlay, example:

   / {
       chosen {
           zephyr,display = &e_display;
       };
   
       aliases {
           display0 = &e_display;
       };
   };
   
   &arduino_spi {
       e_display: il3829@0 {
           compatible = "ilitek,il3829";
           spi-max-frequency = <2000000>;
           status = "okay";
           reg = <0>;
   
           dc-gpios = <&arduino_header 10 GPIO_ACTIVE_HIGH>;     /* D4 */
           reset-gpios = <&arduino_header 14 GPIO_ACTIVE_HIGH>;  /* D8 */
           busy-gpios = <&arduino_header 13 GPIO_ACTIVE_HIGH>;   /* D7 */
   
           width = <200>;
           height = <200>;
       };
   };

4. Create DTS bindings file dts/bindings/ilitek,il3829.yaml in your project:

   description: IL3829 e-paper display controller
   
   compatible: "ilitek,il3829"
   include: [spi-device.yaml]
   
   properties:
   dc-gpios:
       type: phandle-array
       required: true
   
   busy-gpios:
       type: phandle-array
       required: true
   
   reset-gpios:
       type: phandle-array
       required: true
   
   width:
       type: int
       required: true
       description: Width of the display in pixels
   
   height:
       type: int
       required: true
       description: Height of the display in pixels
   

5. Add parameters to project prj.conf:

   CONFIG_DISPLAY=y
   CONFIG_IL3829_DISPLAY=y
   

   For LVGL set also:

   CONFIG_LV_COLOR_DEPTH_32=n
   CONFIG_LV_COLOR_DEPTH_1=y
   

6. Compile, enjoy!

Important note!

As e-paper is very slow, and LVGL fills the display partially, internally driver updates display only after display_blanking_off() execution. So, if you want to see something on display, you have to call display_blanking_off() after lv_task_handler().

Usage example

#include <lvgl.h>
#include <zephyr/drivers/display.h>

void main(void) {
    const struct device * display_dev;

    display_dev = DEVICE_DT_GET(DT_CHOSEN(zephyr_display));

    if (!device_is_ready(display_dev)) {
        LOG_ERR("Display not ready, aborting test");
        return;
    }

    lv_obj_t * timeLabel;

    lv_task_handler();
    display_blanking_off(display_dev);

    timeLabel = lv_label_create(lv_scr_act());
    lv_label_set_text(timeLabel, "BNV");
    lv_obj_align(timeLabel, LV_ALIGN_CENTER, 0, 0);

    /* Infinite loop */
    for (;;) {
        lv_task_handler();
        display_blanking_off(display_dev);
        k_sleep(K_MSEC(10));
    }
}

License

This project is licensed under the MIT License - see the LICENSE file for details

Acknowledgments

• Zephyr Project
• LVGL
• IL3829 datasheet