ST7789V Display

RE: ST7789V Display

mmelv — Thu, 06 Jun 2024 12:37:47 GMT

The problem was that the logic pins were running on 1.8v while the display was power with 3.3v.

RE: ST7789V Display

mmelv — Fri, 31 May 2024 20:21:26 GMT

It didn't seem to help upon initial testing, but I will experiment some more on Monday. My display is 240x320 but messing with the width and height didn't help. I might be missing something else. Really appreciate your responses!

RE: ST7789V Display

letter57 — Fri, 31 May 2024 20:02:07 GMT

Here is my device tree.overlay , perhaps you can compare the differences between the two. Refer to the ST7789V specification to find the differences.

&arduino_spi {
	status = "okay";
	cs-gpios = <&arduino_header 16 GPIO_ACTIVE_LOW>;	/* D10 */

	st7789v_st7789v_waveshare_240x240: st7789v@0 {
		compatible = "sitronix,st7789v";
		spi-max-frequency = <20000000>;
		reg = <0>;
		cmd-data-gpios = <&arduino_header 15 GPIO_ACTIVE_LOW>;	/* D9 */
		reset-gpios = <&arduino_header 14 GPIO_ACTIVE_LOW>;	/* D8 */
		width = <240>;
		height = <240>;
		x-offset = <0>;
		y-offset = <0>;
		vcom = <0x19>;
		gctrl = <0x35>;
		vrhs = <0x12>;
		vdvs = <0x20>;
		mdac = <0x00>;
		gamma = <0x01>;
		colmod = <0x05>;
		lcm = <0x2c>;
		porch-param = [0c 0c 00 33 33];
		cmd2en-param = [5a 69 02 01];
		pwctrl1-param = [a4 a1];
		pvgam-param = [D0 04 0D 11 13 2B 3F 54 4C 18 0D 0B 1F 23];
		nvgam-param = [D0 04 0C 11 13 2C 3F 44 51 2F 1F 1F 20 23];
		ram-param = [00 F0];
		rgb-param = [CD 08 14];
	};
};

RE: ST7789V Display

mmelv — Fri, 31 May 2024 18:00:29 GMT

I'm using Adafruit GFX library to control the pins. They are defined below. I'm also not using the Zephyr display driver. According to my oscilloscope, the signal is identical to each display so I'm thinking that the ST7789V is configured to receive data differently, hence why I thought it might be related to device tree.

RE: ST7789V Display

letter57 — Fri, 31 May 2024 03:30:19 GMT

I think you should not mark off cs-gpios, cmd-data-gpios, and reset-gpios.

When the display device is ready, you need to call blanking_off() to display it correctly.

Please refer to the example code below.

static const struct device    *display_dev;
static const struct display_driver_api *st7789v_api;

static void    wl_display_thread(void *p1, void *p2, void *p3)
{
    int    err;


    display_dev = DEVICE_DT_GET(DT_CHOSEN(zephyr_display));

    LOG_INF("wl_display_thread");

    if(!device_is_ready(display_dev))
    {
        LOG_ERR("Device not ready, aborting test");
        return 0;
    }

    st7789v_api = display_dev->api;
    st7789v_api->blanking_off(display_dev);
   
    setup_ui(&guider_ui);
    events_init(&guider_ui);
    custom_init(&guider_ui);

    while (1)
    {
        lv_task_handler();
        k_sleep(K_MSEC(5));
    }
}