pico-zxspectrum/docs/ZxSpectrumPicomputerZxLcd.md

ZxSpectrumPicomputerZxLcd

This is a target written for Bobricius' PICOZX with built in LCD

It supports:

• USB keyboard
• Keyboard martix
• USB joysticks
• VGA video (RGB222)
• LCD video (ST7789/ILI9341)
• PWM sound (1 pin)
• SPI SD card

By default, the board starts up using the LCD as its display. To boot into VGA mode hold down the 'fire' button during reset. Placing vga.txt on the SD card in the zxspectrum folder changes the default to VGA.

While on the menu...

• SHIFT-Fire = ESC
• RELOAD = Backspace
• SHIFT-RELOAD = Del

Circuit Diagrams

The firmware produces RGB 222 for the VGA out:

Firmware

LCD	Colour Encoding	Colour Channel	VGA	Board	Firmware
ST7789	BGR	Normal	640x480x60Hz	Bobricius	ZxSpectrumPicomputerZxLcd_640x480x60Hz.uf2
ST7789	BGR	Normal	720x576x50Hz	Bobricius	ZxSpectrumPicomputerZxLcd_720x576x50Hz.uf2
ST7789	BGR	Inverted	640x480x60Hz		ZxSpectrumPicomputerZxInverseLcd_640x480x60Hz.uf2
ST7789	BGR	Inverted	720x576x50Hz		ZxSpectrumPicomputerZxInverseLcd_720x576x50Hz.uf2
ILI9341	RGB	inverted	640x480x60Hz		ZxSpectrumPicomputerZxILI9341Lcd_640x480x60Hz.uf2
ILI9341	RGB	inverted	720x576x50Hz		ZxSpectrumPicomputerZxILI9341Lcd_720x576x50Hz.uf2

Build system notes

The make system has some switches to adapt it to different LCD panels:

Symbol	Description	PICOZX	ILI19341
LCD_INVERSE	invert the brightness of the RGB color components	undefined	defined
LCD_MIRROR_X	Mirror the LCD output horizontally	defined	undefined
LCD_RGB	Use RBG order rather than BGR	undefined	defined

References

ILI9341 datasheet
hackster
raspberrypi.com
Bobricius on YouTube
Bobricius PCBWay
Pixel Fandango on YouTube