Single chip microcomputer -- hlk-w801 transplant NES simulator (III)

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Single chip microcomputer —HLK-W801 transplant Nes Simulator （ One ）
Single chip microcomputer —HLK-W801 transplant Nes Simulator （ Two ）

Key points of this chapter — Optimize the display

After the first two chapters , Tested the refresh rate , It's amazing 3 Frames per second

Increase the main frequency

main Function , There is a position for setting clock frequency division , Try to change to maximum

modify LCD initial

default ILI9341 It's a vertical screen ,320*240 Words , We write data , It needs to be truncated , Because every line of this simulator is 256 Characters .
So let's do a horizontal screen , And configure the memory of the drawing range , Let's compare it with the line provided by the simulator buf One-to-one correspondence , Many configuration actions are avoided , Just keep writing .

    ILI9341_WR_REG(0x36);	   //set the model of scanning
	ILI9341_WR_DATA8((1<<5)|(0<<6)|(1<<7)|(1<<3)); // Left horizontal screen 
	
	//ILI9341_WR_DATA8((1<<5)|(1<<6)); Right horizontal screen 
	//ILI9341_WR_DATA8(0x08);  Vertical screen 
	ILI9341_WR_REG(0x2B); 	//set the page address  Horizontal screen settings  Y Axis to 239
	ILI9341_WR_DATA8(0x00);
	ILI9341_WR_DATA8(0x00);
	ILI9341_WR_DATA8(0x00);
	ILI9341_WR_DATA8(0xDF);

	ILI9341_WR_REG(0x2A);    //set the column address X Axis to 319  Change it to 255
	ILI9341_WR_DATA8(0x00);
	ILI9341_WR_DATA8(0x00);
	//ILI9341_WR_DATA8(0x01);
	//ILI9341_WR_DATA8(0x3F);
	ILI9341_WR_DATA8(0x00);
	ILI9341_WR_DATA8(0xFF);
	
	ILI9341_WR_REG(0x2c);// The memory writes 

here , We made a left horizontal screen , And the range of horizontal and vertical coordinates is 256*240.
Then our write screen function can be transformed into the simplest write SPI

void ILI9341_DrawLine(u16 y,u16* data)
{
    
	tls_spi_write((uint8_t *)data,512);
}

Then someone will notice , Used in the front Y The axis should be 239, Conversion to hexadecimal should be EF. But why DF, So it's because of the first line address of the game , It's not from 0 Start , And there are only 0xEF That's ok , So in order to draw the picture in the simplest way , Don't set the row and column address , Then directly configure the vertical coordinate of the display position used as 0xDF. otherwise , There will be a problem of scrolling .

Test frame rate

Then we configured a 5 Second timer , Then we draw each frame , Just remember the data once ,5 Seconds to see how many frames are drawn .

extern unsigned int FrameCount;
static void demo_timer_irq2(u8 *arg)
{
    
	printf("%02d fp/5s\n",(FrameCount));
	FrameCount=0;
}
void  timer_demo(void)
{
    
	u8 timer_id2;
	struct tls_timer_cfg timer_cfg2;

	timer_cfg2.unit = TLS_TIMER_UNIT_MS;
	timer_cfg2.timeout = 5000;
	timer_cfg2.is_repeat = 1;
	timer_cfg2.callback = (tls_timer_irq_callback)demo_timer_irq2;
	timer_cfg2.arg = NULL;
	timer_id2 = tls_timer_create(&timer_cfg2);
	tls_timer_start(timer_id2);
}

Count at drawing image

void InfoNES_LoadLine()
{
    
	if(PPU_Scanline==100)
	{
    
		FrameCount++;
	}
	ILI9341_DrawLine(PPU_Scanline,WorkLine);
}

Finally tested

10fps The level of left and right .

After commenting out the drawing operation , The simulator calculates the frame speed as follows

It's about 28fps. So you can see that drawing is still very time-consuming .

SPI The rate is 20MHZ. Then the maximum transmission per second is about 20 frame .

The calculation per frame is about 0.035 second , The transmission is about 0.05 second , Together, it takes about 0.085 second , So about... Per second 11.7 frame , Remove other operations , About 11 frame /s.

It seems that you still need a parallel port to achieve a high refresh rate .