Rotate screen and dma

Ali_Rostami · December 17, 2019, 12:42pm

Description

I need to rotate my display. I read this comment about it, and as far as I understand we can’t do this with DMA, or even DMA2D. Am I right? Do we have any solution for it?

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

stm32f429igt6, GCC, stm32cubeide

What do you want to achieve?

Rotate the screen while using DMA too.

graeme · December 17, 2019, 2:38pm

Some displays allow to change the mode from portrait to landscape and vice versa. This is normally done when initializing the display and would be independent of littlevgl. If your display supports this then you should still be able to use DMA etc. You wold have to tell littlevgl what the new size is i.e. if it was 320x240 then it would now be 240x320 .

Maybe look for data sheet or example code for ILI9341 and modify the the driver. Code will be in function such as
void ili9341_Init(void)
{
//Multiple register writes
}

Hope this helps

graeme · December 17, 2019, 2:47pm

Also look here. There is a rotation function using ILI9341 registers:

gist.github.com

https://gist.github.com/postmodern/ed6e670999f456ad9f13

ili9341.c

#include "ili9341.h"

volatile uint16_t LCD_W=ILI9341_TFTWIDTH;
volatile uint16_t LCD_H=ILI9341_TFTHEIGHT;

void ili9341_hard_init(void)//init hardware
{
	rstddr=0xFF;//output for reset
	rstport |=(1<<rst);//pull high for normal operation
	controlddr|=(1<<dc);//D/C as output

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ili9341.h

#ifndef _ILI9341_H_
#define _ILI9341_H_

#include <avr/io.h>
#include <util/delay.h>
#include <avr/pgmspace.h>
#include <limits.h>
#include <inttypes.h>

#define controlport PORTB

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ili9341gfx.c

#include "ili9341.h"
#include "ili9341gfx.h"

volatile uint16_t cursor_x;
volatile uint16_t cursor_y;
volatile uint16_t textcolour;
volatile uint16_t textbgcolour;
volatile uint8_t textsize;
uint16_t vsetx,vsety,vactualx,vactualy,isetx,isety,iactualx,iactualy;

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Ali_Rostami · December 17, 2019, 7:33pm

Hmm, yeah thanks. I knew it. Unfortunately, my LCD doesn’t support it.