HLK-W801-LVGL8 horizontal screen display

Preface

A few days ago, we have completed the transplantation of LVGL to W801, and the effect is shown in the following figure:

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The picture is displayed in portrait mode because the screen has a resolution of 240x320. If it is to be displayed in landscape mode, that is, how to configure the screen as 320x240? I originally wanted to achieve this goal by directly configuring some configuration parameters in LVGL, but there are several problems in actual operation. In LVGL, sw_rotate=1, rotated=LV_DISP_ROT_90 can be used to achieve the rotation purpose, but the actual effect is indeed low frame rate and high CPU usage caused by software implementation, and the picture can only display 240*320 effect after rotation, not widescreen display. So here I am thinking about how to use the display driver function in ILI9325 to achieve this (that is, the ILI9235 driver configuration displays a 90° rotation)

Analysis of normal vertical screen display

As shown in the figure, the F1 area displays vertically:

Screen horizontal H: vertical V = 240: 320

Screen origin coordinates O1(0,0)

In the lvgl interface function flush, the area filling needs to be implemented. For details, please refer to the LCD driver here for the basic steps:

1) Configure Entry Mode (R03h)

Bit3 AM，Bit4:5=ID0:1

AM=0,ID0:1=3

2) Window Area ((R50h, R51h, R52h, R53h) and starting coordinates (R20h, R21h) when filling the F1 area

Set the start/end coordinates of the fill area

reg ：

0x50 set h1

0x51 set h2

0x52 set v1

0x53 set v2

Set the starting coordinate address

reg：

0x20 set h1

0x21 set v1

Anatomy of a horizontal display

As shown in the figure, the F1 area displays horizontally:

The horizontal screen display is regarded as rotating the screen 90° clockwise, but the screen horizontal X: vertical Y = 320: 240

The displayed starting point coordinates become O2(0,0)

In the lvgl interface function flush, area filling needs to be implemented.

1) Configure Entry Mode (R03h)

Bit3 AM，Bit4:5=ID0:1

AM=1,ID0:1=2, here set ORG=1, then the starting point coordinates change from O1(0,0) to O2(0,0)

2) Window Area ((R50h, R51h, R52h, R53h) and starting coordinates (R20h, R21h) when filling the F1 area

Here is the key point: because the starting and ending points of the filled area are still determined by the screen origin coordinates O1(0,0), when ORG=1 is adjusted, the area filled by the O2 coordinate system needs to be converted to the O1 coordinate system.

As shown in the figure, the starting and ending coordinates of the F1 area are O2(x1,y1), O2(x2,y2),

When configuring the window area, you need to configure it as O1(h1,v1),O1(h2,v2)

According to the coordinate relationship of the screen, it can be concluded that:

Set the start/end coordinates of the fill area

reg ：

0x50 set h1=239-y2

0x51 set h2=239-y1

0x52 set v1=x1

0x53 set v2=x2

Set the starting coordinate address

reg：

0x20 set x1

0x21 set y1

The flush interface is implemented as follows:

display effect

Note here that the touch coordinates also need to convert some coordinates:

O1(h3,v3) -> O2(x3=v3,y3=239-h3)