nRF5340 LVGL driving adafruit 2.8 display, keyboard corruption / crashing

Question

I started with the ncs-display-ble-example which worked fine. Next I took the LVGL lv_demo_widget, ran it in the simulator using visual studio 2019 where it ran fine. Then I replaced most of the code in gui.c in the ble example with my gui code. It almost works, but not quite.

The UI uses a tab view with three tabs. Each tab has an assortment of controls such as a roller, textarea, checkboxs, sliders, and a list. When I run it I get an exception. If I leave either of the tabs empty it works "mostly" fine, the only problem is when I tap the textarea the keyboard works but looks corrupted. Removing controls tends to make it work better and adding controls makes it worse. The location of the exception moves depending on how many controls are being created. Sometimes it fails while adding a control or style,, or drawing a rect or doing a memalloc.

Any suggestions on how to debug this? Are there limitations in using lvgl with the 5340?

Here is my gui.c replacement:

#include "gui.h"
#include <zephyr.h>
#include <device.h>
#include <drivers/display.h>
#include <lvgl.h>
#include <stdio.h>
#include <string.h>

const struct device *display_dev;


////////////////////////////////////////////////////////////
/**********************
 *  STATIC PROTOTYPES
 **********************/
static void badges_create(lv_obj_t * parent);
static void configure_create(lv_obj_t * parent);
static void analysis_create(lv_obj_t * parent);
static void slider_event_cb(lv_obj_t * slider, lv_event_t e);
static void ta_event_cb(lv_obj_t * ta, lv_event_t e);
static void kb_event_cb(lv_obj_t * ta, lv_event_t e);

/**********************
 *  STATIC VARIABLES
 **********************/
static lv_obj_t * tv;
static lv_obj_t * t1;
static lv_obj_t * t2;
static lv_obj_t * t3;
static lv_obj_t * kb;

static lv_style_t style_box;
static lv_style_t style_tab;





void lv_demo_widgets(void)
{
    tv = lv_tabview_create(lv_scr_act(), NULL);

    lv_style_init(&style_tab);

    lv_style_set_pad_top(&style_tab, LV_STATE_DEFAULT, LV_DPX(1));
    lv_style_set_pad_bottom(&style_tab, LV_STATE_DEFAULT, LV_DPX(5));
    lv_style_set_pad_left(&style_tab, LV_STATE_DEFAULT, LV_DPX(1));
    lv_style_set_pad_right(&style_tab, LV_STATE_DEFAULT, LV_DPX(1));
//    lv_style_set_text_font(&style_tab, LV_STATE_DEFAULT, &lv_font_montserrat_14);
    lv_obj_reset_style_list(tv, LV_TABVIEW_PART_TAB_BTN); /*Remove the styles,coming from the theme*/
    lv_obj_add_style(tv, LV_TABVIEW_PART_TAB_BTN, &style_tab);

    t1 = lv_tabview_add_tab(tv, "Badges");
    t2 = lv_tabview_add_tab(tv, "Configure");
    t3 = lv_tabview_add_tab(tv, "Analysis");


    lv_style_init(&style_box);
    lv_style_set_value_align(&style_box, LV_STATE_DEFAULT, LV_ALIGN_OUT_TOP_LEFT);
    lv_style_set_value_ofs_y(&style_box, LV_STATE_DEFAULT, - LV_DPX(25));
    lv_style_set_margin_top(&style_box, LV_STATE_DEFAULT, LV_DPX(1));
    lv_style_set_pad_top(&style_box, LV_STATE_DEFAULT, LV_DPX(1));
    lv_style_set_pad_bottom(&style_box, LV_STATE_DEFAULT, LV_DPX(1));
    lv_style_set_pad_left(&style_box, LV_STATE_DEFAULT, LV_DPX(1));
    lv_style_set_pad_right(&style_box, LV_STATE_DEFAULT, LV_DPX(1));

//    lv_style_set_text_font(&style_box, LV_STATE_DEFAULT, &lv_font_montserrat_14);

    badges_create(t1);
    configure_create(t2);
//    analysis_create(t3);



}

static void badges_create(lv_obj_t * parent)
{
    lv_obj_t* roller = lv_roller_create(parent, NULL);
    lv_obj_add_style(roller, LV_CONT_PART_MAIN, &style_box);
    lv_obj_set_style_local_value_str(roller, LV_CONT_PART_MAIN, LV_STATE_DEFAULT, "Roller");
    lv_roller_set_auto_fit(roller, false);
    lv_roller_set_visible_row_count(roller, 5);
    lv_obj_set_width(roller, 80);
    lv_obj_set_pos(roller, 10, 5);

    lv_roller_set_options(roller, "Alpha\nBravo\nCharlie\nDelta\nEcho\nZulu", LV_ROLLER_MODE_NORMAL);


    lv_obj_t * ta = lv_textarea_create(parent, NULL);
    lv_obj_add_style(ta, LV_CONT_PART_MAIN, &style_box);

    lv_textarea_set_one_line(ta, true);
    lv_textarea_set_text(ta, "");
    lv_textarea_set_placeholder_text(ta, "Name");
    lv_obj_set_event_cb(ta, ta_event_cb);
    lv_obj_set_width(ta, 180);
    lv_obj_set_pos(ta, 105, 10);


    lv_obj_t* cb = lv_checkbox_create(parent, NULL);
    lv_obj_add_style(cb, LV_CONT_PART_MAIN, &style_box);
    lv_checkbox_set_text(cb, "Virus");
    lv_obj_set_pos(cb, 105, 40);

    cb = lv_checkbox_create(parent, NULL);
    lv_obj_add_style(cb, LV_CONT_PART_MAIN, &style_box);
    lv_checkbox_set_text(cb, "Mask");
    lv_obj_set_pos(cb, 105, 70);

    cb = lv_checkbox_create(parent, NULL);
    lv_obj_add_style(cb, LV_CONT_PART_MAIN, &style_box);
    lv_checkbox_set_text(cb, "Vaccine");
    lv_obj_set_pos(cb, 105, 100);

    lv_obj_t* btn = lv_btn_create(parent, NULL);
    lv_obj_t* label = lv_label_create(btn, NULL);
    lv_obj_add_style(label, LV_CONT_PART_MAIN, &style_box);
    lv_label_set_text(label, "Scan");
    lv_obj_set_width(btn, 75);
    lv_obj_set_pos(btn, 110, 150);

    btn = lv_btn_create(parent, NULL);
    label = lv_label_create(btn, NULL);
    lv_obj_add_style(label, LV_CONT_PART_MAIN, &style_box);
    lv_label_set_text(label, "Remove");
    lv_obj_set_width(btn, 75);
    lv_obj_set_pos(btn, 210, 150);
}

static void configure_create(lv_obj_t * parent)
{
    lv_obj_t* dd = lv_dropdown_create(parent, NULL);
    lv_obj_add_style(dd, LV_CONT_PART_MAIN, &style_box);
    lv_obj_set_style_local_value_str(dd, LV_CONT_PART_MAIN, LV_STATE_DEFAULT, "Dropdown");
    lv_obj_set_width(dd, 200);
    lv_dropdown_set_options(dd, "Proximity\nSimulate");
    lv_obj_set_pos(dd, 4, 5);

    lv_obj_t* label = lv_label_create(parent, NULL);
    lv_obj_add_style(label, LV_CONT_PART_MAIN, &style_box);
    lv_label_set_text(label, "Rows");
    lv_obj_set_pos(label, 4, 40);

    lv_obj_t* slider = lv_slider_create(parent, NULL);
    lv_slider_set_value(slider, 40, LV_ANIM_OFF);
    lv_obj_set_event_cb(slider, slider_event_cb);
    lv_obj_set_pos(slider, 55, 45);


    /*Use the knobs style value the display the current value in focused state*/
    lv_obj_set_style_local_margin_top(slider, LV_SLIDER_PART_BG, LV_STATE_DEFAULT, LV_DPX(25));
    lv_obj_set_style_local_value_font(slider, LV_SLIDER_PART_KNOB, LV_STATE_DEFAULT, lv_theme_get_font_small());
    lv_obj_set_style_local_value_ofs_y(slider, LV_SLIDER_PART_KNOB, LV_STATE_FOCUSED, -LV_DPX(25));
    lv_obj_set_style_local_value_opa(slider, LV_SLIDER_PART_KNOB, LV_STATE_DEFAULT, LV_OPA_TRANSP);
    lv_obj_set_style_local_value_opa(slider, LV_SLIDER_PART_KNOB, LV_STATE_FOCUSED, LV_OPA_COVER);
    lv_obj_set_style_local_transition_time(slider, LV_SLIDER_PART_KNOB, LV_STATE_DEFAULT, 300);
    lv_obj_set_style_local_transition_prop_5(slider, LV_SLIDER_PART_KNOB, LV_STATE_DEFAULT, LV_STYLE_VALUE_OFS_Y);
    lv_obj_set_style_local_transition_prop_6(slider, LV_SLIDER_PART_KNOB, LV_STATE_DEFAULT, LV_STYLE_VALUE_OPA);

    label = lv_label_create(parent, NULL);
    lv_obj_add_style(label, LV_CONT_PART_MAIN, &style_box);
    lv_label_set_text(label, "Space");
    lv_obj_set_pos(label, 4, 90);

    slider = lv_slider_create(parent, NULL);
    lv_slider_set_value(slider, 40, LV_ANIM_OFF);
    lv_obj_set_event_cb(slider, slider_event_cb);
    lv_obj_set_pos(slider, 55, 95);


    /*Use the knobs style value the display the current value in focused state*/
    lv_obj_set_style_local_margin_top(slider, LV_SLIDER_PART_BG, LV_STATE_DEFAULT, LV_DPX(25));
    lv_obj_set_style_local_value_font(slider, LV_SLIDER_PART_KNOB, LV_STATE_DEFAULT, lv_theme_get_font_small());
    lv_obj_set_style_local_value_ofs_y(slider, LV_SLIDER_PART_KNOB, LV_STATE_FOCUSED, -LV_DPX(25));
    lv_obj_set_style_local_value_opa(slider, LV_SLIDER_PART_KNOB, LV_STATE_DEFAULT, LV_OPA_TRANSP);
    lv_obj_set_style_local_value_opa(slider, LV_SLIDER_PART_KNOB, LV_STATE_FOCUSED, LV_OPA_COVER);
    lv_obj_set_style_local_transition_time(slider, LV_SLIDER_PART_KNOB, LV_STATE_DEFAULT, 300);
    lv_obj_set_style_local_transition_prop_5(slider, LV_SLIDER_PART_KNOB, LV_STATE_DEFAULT, LV_STYLE_VALUE_OFS_Y);
    lv_obj_set_style_local_transition_prop_6(slider, LV_SLIDER_PART_KNOB, LV_STATE_DEFAULT, LV_STYLE_VALUE_OPA);

    label = lv_label_create(parent, NULL);
    lv_obj_add_style(label, LV_CONT_PART_MAIN, &style_box);
    lv_label_set_text(label, "Rate");
    lv_obj_set_pos(label, 4, 140);

    slider = lv_slider_create(parent, NULL);
    lv_slider_set_value(slider, 40, LV_ANIM_OFF);
    lv_obj_set_event_cb(slider, slider_event_cb);
    lv_obj_set_pos(slider, 55, 145);


    /*Use the knobs style value the display the current value in focused state*/
    lv_obj_set_style_local_margin_top(slider, LV_SLIDER_PART_BG, LV_STATE_DEFAULT, LV_DPX(25));
    lv_obj_set_style_local_value_font(slider, LV_SLIDER_PART_KNOB, LV_STATE_DEFAULT, lv_theme_get_font_small());
    lv_obj_set_style_local_value_ofs_y(slider, LV_SLIDER_PART_KNOB, LV_STATE_FOCUSED, -LV_DPX(25));
    lv_obj_set_style_local_value_opa(slider, LV_SLIDER_PART_KNOB, LV_STATE_DEFAULT, LV_OPA_TRANSP);
    lv_obj_set_style_local_value_opa(slider, LV_SLIDER_PART_KNOB, LV_STATE_FOCUSED, LV_OPA_COVER);
    lv_obj_set_style_local_transition_time(slider, LV_SLIDER_PART_KNOB, LV_STATE_DEFAULT, 300);
    lv_obj_set_style_local_transition_prop_5(slider, LV_SLIDER_PART_KNOB, LV_STATE_DEFAULT, LV_STYLE_VALUE_OFS_Y);
    lv_obj_set_style_local_transition_prop_6(slider, LV_SLIDER_PART_KNOB, LV_STATE_DEFAULT, LV_STYLE_VALUE_OPA);
}

static void analysis_create(lv_obj_t * parent)
{

    lv_obj_t* btn;
    lv_obj_t* list = lv_list_create(parent, NULL);
    lv_obj_add_style(list, LV_CONT_PART_MAIN, &style_box);
    lv_list_set_scroll_propagation(list, true);
    lv_obj_set_size(list, 120, 190);
    lv_obj_set_pos(list, 5, 5);

    const char* txts[] = { LV_SYMBOL_SAVE, "Save", LV_SYMBOL_CUT, "Cut", LV_SYMBOL_COPY, "Copy",
            LV_SYMBOL_OK, "This", LV_SYMBOL_EDIT, "Edit", LV_SYMBOL_WIFI, "Wifi",
            LV_SYMBOL_BLUETOOTH, "Bluetooth",  LV_SYMBOL_GPS, "GPS", LV_SYMBOL_USB, "USB",
            LV_SYMBOL_SD_CARD, "SD card", LV_SYMBOL_CLOSE, "Close", NULL };

    uint32_t i;
    for (i = 0; txts[i] != NULL; i += 2) {
        btn = lv_list_add_btn(list, txts[i], txts[i + 1]);
    }

    lv_obj_t* bar = lv_bar_create(parent, NULL);
    lv_obj_set_width(bar, 150);
    lv_obj_set_style_local_value_font(bar, LV_BAR_PART_BG, LV_STATE_DEFAULT, lv_theme_get_font_small());
    lv_obj_set_style_local_value_align(bar, LV_BAR_PART_BG, LV_STATE_DEFAULT, LV_ALIGN_OUT_BOTTOM_MID);
    lv_obj_set_style_local_value_ofs_y(bar, LV_BAR_PART_BG, LV_STATE_DEFAULT, LV_DPI / 20);
    lv_obj_set_style_local_margin_bottom(bar, LV_BAR_PART_BG, LV_STATE_DEFAULT, LV_DPI / 7);
    lv_obj_align(bar, NULL, LV_ALIGN_CENTER, 0, 0);
    lv_bar_set_value(bar, 30, LV_ANIM_OFF);
    lv_obj_set_pos(bar, 150, 150);

    btn = lv_btn_create(parent, NULL);
    lv_obj_add_style(btn, LV_CONT_PART_MAIN, &style_box);
    lv_obj_t* label = lv_label_create(btn, NULL);
    lv_obj_add_style(label, LV_CONT_PART_MAIN, &style_box);
    lv_label_set_text(label, "RESET");
    //lv_label_set_text(label, LV_SYMBOL_PREV);
    lv_obj_set_width(btn, 50);
    lv_obj_set_pos(btn, 140, 100);

    btn = lv_btn_create(parent, NULL);
    lv_obj_add_style(btn, LV_CONT_PART_MAIN, &style_box);
    label = lv_label_create(btn, NULL);
    lv_obj_add_style(label, LV_CONT_PART_MAIN, &style_box);
    lv_label_set_text(label, "PLAY");
    //lv_label_set_text(label, LV_SYMBOL_PLAY);
    lv_obj_set_width(btn, 50);
    lv_obj_set_pos(btn, 200, 100);

    btn = lv_btn_create(parent, NULL);
    lv_obj_add_style(btn, LV_CONT_PART_MAIN, &style_box);
    label = lv_label_create(btn, NULL);
    lv_obj_add_style(label, LV_CONT_PART_MAIN, &style_box);
    lv_label_set_text(label, "NEXT");
//    lv_label_set_text(label, LV_SYMBOL_NEXT);
    lv_obj_set_width(btn, 50);
    lv_obj_set_pos(btn, 260, 100);
}




static void slider_event_cb(lv_obj_t * slider, lv_event_t e)
{
    if(e == LV_EVENT_VALUE_CHANGED) {
        if(lv_slider_get_type(slider) == LV_SLIDER_TYPE_NORMAL) {
            static char buf[16];
            lv_snprintf(buf, sizeof(buf), "%d", lv_slider_get_value(slider));
            lv_obj_set_style_local_value_str(slider, LV_SLIDER_PART_KNOB, LV_STATE_DEFAULT, buf);
        } else {
            static char buf[32];
            lv_snprintf(buf, sizeof(buf), "%d-%d", lv_slider_get_left_value(slider), lv_slider_get_value(slider));
            lv_obj_set_style_local_value_str(slider, LV_SLIDER_PART_INDIC, LV_STATE_DEFAULT, buf);
        }

    }
}



static void ta_event_cb(lv_obj_t * ta, lv_event_t e)
{
    if(e == LV_EVENT_RELEASED) {
        if(kb == NULL) {
            lv_coord_t kb_height = LV_MATH_MIN(LV_VER_RES / 2, LV_DPI * 4 / 3);
            lv_obj_set_height(tv, LV_VER_RES - kb_height);
            kb = lv_keyboard_create(lv_scr_act(), NULL);
    lv_obj_add_style(kb, LV_CONT_PART_MAIN, &style_box);
            lv_obj_set_height(kb, kb_height);
            lv_obj_align(kb, NULL, LV_ALIGN_IN_BOTTOM_MID, 0, 0);
            lv_obj_set_event_cb(kb, kb_event_cb);

            lv_indev_wait_release(lv_indev_get_act());
        }
        lv_textarea_set_cursor_hidden(ta, false);
        lv_page_focus(t1, lv_textarea_get_label(ta), LV_ANIM_ON);
        lv_keyboard_set_textarea(kb, ta);
    } else if(e == LV_EVENT_DEFOCUSED) {
        lv_textarea_set_cursor_hidden(ta, true);
    }
}

static void kb_event_cb(lv_obj_t * _kb, lv_event_t e)
{
    lv_keyboard_def_event_cb(kb, e);

    if(e == LV_EVENT_CANCEL) {
        if(kb) {
            lv_obj_set_height(tv, LV_VER_RES);
            lv_obj_del(kb);
            kb = NULL;
        }
    }
}



//////////////////////////////////////////////////////////////////



void gui_init(gui_config_t * config)
{
	
}

void gui_set_bt_state(gui_bt_state_t state)
{

}

void gui_set_bt_led_state(bool led_is_on)
{
	
}


void gui_run(void)
{
	display_dev = device_get_binding(CONFIG_LVGL_DISPLAY_DEV_NAME);

	if (display_dev == NULL) {
//		LOG_ERR("Display device not found!");
		return;
	}

        lv_demo_widgets();

	display_blanking_off(display_dev);

	while(1){
//		process_cmd_msg_queue();
		lv_task_handler();
		k_sleep(K_MSEC(20));
	}
}

// Define our GUI thread, using a stack size of 4096 and a priority of 7
K_THREAD_DEFINE(gui_thread, 4096, gui_run, NULL, NULL, NULL, 7, 0, 0);

Here is the updated prj.conf with the additional controls enabled.

CONFIG_HEAP_MEM_POOL_SIZE=16384
CONFIG_MAIN_STACK_SIZE=4096

CONFIG_DISPLAY=y
CONFIG_DISPLAY_LOG_LEVEL_ERR=y

CONFIG_LOG=n

CONFIG_LVGL=y
CONFIG_LVGL_ANTIALIAS=y
CONFIG_LVGL_USE_LABEL=y
CONFIG_LVGL_USE_CONT=y
CONFIG_LVGL_USE_BTN=y
CONFIG_LVGL_USE_CHECKBOX=y
CONFIG_LVGL_USE_IMG=y
CONFIG_LVGL_USE_THEME_MATERIAL=y
CONFIG_LVGL_USE_ANIMATION=y
CONFIG_LVGL_USE_SHADOW=y

CONFIG_LVGL_USE_PAGE=y
CONFIG_LVGL_USE_BTNMATRIX=y
CONFIG_LVGL_USE_TABVIEW=y
CONFIG_LVGL_USE_DROPDOWN=y
CONFIG_LVGL_USE_ROLLER=y
CONFIG_LVGL_USE_KEYBOARD=y
CONFIG_LVGL_USE_BAR=y
CONFIG_LVGL_USE_SLIDER=y
CONFIG_LVGL_USE_LIST=y
CONFIG_LVGL_USE_TEXTAREA=y

CONFIG_NEWLIB_LIBC=y

CONFIG_BT=y
CONFIG_BT_PERIPHERAL=y
CONFIG_BT_DEVICE_NAME="Nordic_Blinky"

# Enable the LBS service
CONFIG_BT_LBS=y

Alan · Answer

The corrupted keyboard (and other symbol issues) was related to the text encoding and the fonts. Enabling UTF8 text encoding and using one of the LVGL fonts made that part of it work better. I added this to my prj.conf file and got much better results: 
 CONFIG_LVGL_TXT_ENC_UTF8=y 
 CONFIG_LVGL_FONT_MONTSERRAT_14=y 
 CONFIG_LVGL_THEME_DEFAULT_FONT_NORMAL_MONTSERRAT_14=y 
 I was still having crashing issues with the tabbed view version of the GUI, so I simplified it and recreated it without the tabbed views. It didn't look as nice but it works without issues.