How to change partial buffer drawing from rows to columns?

[PWagn.1]

Hello,

Is it possible to change partial buffer drawing from pixel rows to columns?

I have partial buffer allocated for 3 rows (lines), so that lines 1-3 are drawn first, then lines 4-6, 7-9 ...

I would like to change it to rows: rows 1-3 first, then 4-6....

Background:

Our display has native orientation in columns (we use it rotated by 90 degrees) and the fact that TouchGFX generates update by rows and display is refreshed column-wise causes very visible diagonal tearing effect. Having the tear line vertical would be less irritating.

 

Thanks,

Petr

[Yoann KLEIN]

Hello @PWagn.1​ ,

Unfortunately the answer is no, you cannot change the drawing orientation from rows to columns.

Can you please share your display type (or manual) ? We would like to understand why your display native drawing orientation is vertical and not horizontal.

Thanks,

/Yoann

[PWagn.1]

Hi Yoann,

inside the display there is ST7789V2 driver (used in Display data RAM mode + TouchGFX with partial buffer), datasheet is available e.g. here:

https://m5stack.oss-cn-shenzhen.aliyuncs.com/resource/docs/datasheet/unit/lcd/ST7789V2_SPEC_V1.0.pdf

which (per my understanding) natively support resolution 240x320 (the screen in portrait orientation), whereas I would like to use it in landscape orientation (320x240), hence the rotation by 90° and rows changed to columns.

Thanks,

Petr

[MM..1]

Study MADCTL register in LCD

[PWagn.1]

Hi,
Thank you for your answer, but I believe nothing in MADCTL register is the answer.
The bits MX, MY , MV allows you to set the orientation of image in the display RAM (the orientation change between MCU and DDRAM), but they do not affect the process, how the picture is updated on LCD panel.
On the other hand, the bits ML and MH affect exactly that process (by setting which line is send first and which pixel within the line is send first), but the ability to change rows to columns and vice versa is missing.
Thanks,
Petr