Horizontal screen update

I remember reading in a post recently that updating the screen horizontally rather than vertically resulted in some kind of issue. I can’t remember which thread I read it in, but I just did a test as an attempt to speed up Pokkitris a little.

//----------------------------------------------- in screen init sequence...
    write_command(0x03); // Entry mode... lets try if this affects the direction
    write_data(0x1038); // originally 0x1030 1000000110000 BGR,ID1,ID0
                        // test 1: 0x1038 1000000111000 BGR,ID1,ID0,AM=1 ->drawing DRAM horizontally

void Pokitto::setWindow(uint8_t x1, uint8_t y1, uint8_t x2, uint8_t y2) {
	write_command(0x37); write_data(x1);
	write_command(0x36); write_data(x2);
	write_command(0x39); write_data(y1);
	write_command(0x38); write_data(y2);
	write_command(0x20); write_data(x1);
	write_command(0x21); write_data(y1);

void Pokitto::lcdRefreshMode1(uint8_t * scrbuf, uint16_t* paletteptr) {
	setWindow(0, 0, 175, 219);
    uint8_t pix;
    uint8_t quartWide=55; // 220/4;
    uint8_t pic;
    for(int y=0; y<176; y++){
        for(int x=0; x<quartWide; x++){
            pic = scrbuf[x+quartWide*y];
            pix = (pic >> 6)&3; write_data(paletteptr[pix]);
            pix = (pic >> 4)&3; write_data(paletteptr[pix]);
            pix = (pic >> 2)&3; write_data(paletteptr[pix]);
            pix = pic &3;       write_data(paletteptr[pix]);

and it seem to update fine. What exactly was this issue?

1 Like

The screen I used for development was same ic but by a different manufacturer.IDK if this affected the outcome

@spinal : where are you uploading this code so I can try it?

Nowhere yet, don’t know how.

but you are coding it online, yes?

@jonne - this one, nope

in embitz?

yes. ----------------must be 10 characters

well, did you (edit:) fork the repository? if yes, just do a pull request