Setting rotated option in lv_disp_drv_t causes hard fault

How-to
1

Description

stm32f746_discovery_no_os demo program hard faults when i try to rotate the display.

What MCU/Processor/Board and compiler are you using?

STM32 F746 discovery board + SW4STM32 IDE

What do you want to achieve?

I want to rotate the display clock wise by 90 Deg.

What have you tried so far?

I tested this feature in the simulator and it works fine. I changed the following things in the simulator.
in win_drv.c
disp_drv.rotated = 1;

in lv_drv_conf.h

define WINDOW_HOR_RES 272

define WINDOW_VER_RES 480

in lv_conf.h
#define LV_HOR_RES_MAX (272)
#define LV_VER_RES_MAX (480)

When i make similar changes in the STM32 program, i get a hard fault.

What could be the issue?

Thanks

2 Likes
2

LV_HOR_RES_MAX is used as size of a line buffer. After rotation the line length is 480, so either use landscape as default orientation or use 480 for both HOR and RES

3

The rotated option requires additional logic in the driver which I haven’t implemented yet, so it’s not going to work at the moment. Sorry about that.

4

@beppone: @polmon already mentioned that he has changed the appropriate defines to the correct values.

5

Can i rotate the buf_to_flush array while copying to my_fb?

6

You can, just read buf_to_flush column-by-column instead of it’s row-by-row.

7

I have tried the following code to read col by col. But i cant seem to find the issue.

I made the screen into a 272 x 272 square.

for (x_fill_act = x1_flush ; x_fill_act <= x2_flush; x_fill_act++)
{
for(y_fill_act = act_y1; y_fill_act <= y2_fill; y_fill_act ++)
{
memcpy((uint32_t)&my_fb[(271 - x_fill_act) * 272 + y_fill_act], (uint32_t)(buf_to_flush + (272*y_fill_act + x_fill_act)),2);
}
}

8

I managed to get it ALMOST working with the following code.

  for (x_fill_act = x2_flush ; x_fill_act >= x1_flush; x_fill_act--)
{
	  for(y_fill_act = act_y1; y_fill_act <= y2_fill; y_fill_act ++)
	{
       memcpy((uint32_t)&my_fb[(271 - x_fill_act) * (272) + y_fill_act], (uint32_t)(buf_to_flush + x_fill_act + (y_fill_act - act_y1)*(x2_flush - x1_flush + 1)),2);
	}
}

However there is still some issue with the copying algorithm. I get the following issue in the attached picture.

20190815_002706
20190815_002706.jpg3024Ă—4032 2.81 MB

9

Later today I’ll create an an example rotate function.

1 Like
10

Here is the code which worked me in the simulator:


void get_col(const lv_color_t * src, const lv_area_t * area, lv_coord_t y, lv_color_t * dest)
{
    lv_coord_t w = lv_area_get_width(area);
    lv_coord_t h = lv_area_get_height(area);

    lv_coord_t i;
    for(i = 0; i < h; i++) {
        dest[i].full = src[y].full;
        src += w ;
    }
}

void monitor_flush(lv_disp_drv_t * disp_drv, const lv_area_t * area, lv_color_t * color_p) 
{
    lv_coord_t x2 = area->x2;
    if(x2 >= disp_drv->ver_res) x2 = MONITOR_VER_RES - 1;

    lv_color_t * dest = (lv_color_t *)monitor.tft_fb;
    dest +=  MONITOR_HOR_RES * (MONITOR_VER_RES - 1);
    dest -= MONITOR_HOR_RES * area->x1;

    lv_coord_t x;
    for(x = area->x1; x <= x2; x++) {
          get_col(color_p, area, (x - area->x1), dest + area->y1);
          dest -= MONITOR_HOR_RES;
    }
}

image

1 Like
11

Works like a charm! Thank you!

12

Great! :slight_smile:
It was already asked a lot times. Good to know that there is a working reference code now.

13

polmon can you post your results?

14

what is monitor.tft_fb and how to define it?

15

It’s the target frame buffer.

However now display rotation is available as built-in feature too. See Display interface — LVGL documentation

1 Like
16

Hi,

What is this “monitor.tft_fb” buffer, And where should I get its location in LVGL 9.1.1

17

It’s an old topic. Please open a new topic one to describe what you are trying to achieve and with which LVGL version.

18

New thread created, Please follow below link

19

yes in rk3566 i meet the same problem