[ARM] Increase SPI TFT display speed

[Montassar Ghanmy]

Hi there , thank you for taking a look at my thread.
The question is "Does increasing the SPI Frequency Increase the TFT Bitmap loading speed ? ". I have my bitmap stored within an array and it works fine but the loading of the image takes about 2 secs.
Is it also possible if I would change the algorithm which I'm currently using: it's a loop that fills a pixel , then jumps to the next one, something like this:

for(int Y = 0; Y < 128; Y++) {
for(int X = 0; X < 128; X++) {
int currentPosition = X + Y * 128
writePixel(X,Y,bitmap[currentPosition]);
}
}

By the way I'm using a Cortex M4.
Thank you !!!!! :thumbsup:

 

[Easyrider83]

Use winows filling method.
Just an example:

void ILI9340_DrawPic16 (unsigned int x0, unsigned int y0, unsigned int SizeX, unsigned int SizeY, unsigned int * Pic)
{
	unsigned long Cnt = SizeX * SizeY;
	ILI9340_SetAddrWindow(x0, y0, x0 + SizeX, y0 + SizeY);
  GPIO_SetBits(LCD_DC);
	GPIO_ResetBits(LCD_CS);
	while (Cnt--)
	{
		  SPI_SendByte(LCD_SPI, * Pic >> 8);
			SPI_SendByte(LCD_SPI, (char)* Pic++);
	}
	GPIO_SetBits(LCD_CS);
}

 

[Montassar Ghanmy]

Hi there , thankx for replying. Based on what you advice and what I have here, I made something like this:

	int Cnt = 128 * 128;
	int i = 1;
	SetAddrWindow(0,0,128,128);
	while (Cnt--) {
		writeData16(mainscreen[i]);
		i++;
	}

But I got 2 small issues:
-The image is rotated now , like in landscape instead of vertically showing up, any ideas how can I rotate it back ?
-The speed has significantly increase and the loading time is less but how can I make it even less. I want to display like 10fps ? or even 5fps ?
Thank you again !!!:thumbsup:

 

[Easyrider83]

128 х 128 х 16bit x 10fps = 2621440 Hz SPI Clock. You can expect for 30+fps even.
Rotating in RAM or sort data during sending, but it will increase cpu load and affect to refresh rate.
Do you have a 32k RAM free for image processing?

 

[Montassar Ghanmy]

Definitely I have 32K RAM free but how so I sort the data during sending or within the RAM exactly in code please , thank you.
BTW is the TFT controller okay with what's so ever the SPI frequency is ?

 

[Easyrider83]

You need to convert rows to collums or conversely

 

[Montassar Ghanmy]

Any code example please on how can i get that to happen ? That would be amazing ! It's because i can't figure it out on my own.