Pins for ST7735 Touchscreen

[espruino-discuss3]

Posted at 2020-07-10 by lloydwatkin

Hi all,

Complete electronics luddite here. I have the following LCD touchscreen for a project which uses the following chipsets:

• Screen https://www.espruino.com/ST7735
• Touch https://www.espruino.com/XPT2046

I'm just wondering if someone can help me identify the pins and how they map to those on the ST7735 (and if you want to be really helpful how I'd wire these up to an espruino wifi).

Thanks, Lloyd.

Attachments:

• IMG_20200710_113052.jpg

[gfwilliams]

Posted at 2020-07-10 by @gfwilliams

Hi! I guess it's this one? https://uk.banggood.com/1_8-Inch-LCD-Screen-SPI-Serial-Port-Module-TFT-Color-Display-Touch-Screen-ST7735-p-1414465.html?cur_warehouse=CN

If so:

Number	Name	1.8 inch TFT LCD
1	GND	Power ground
2	VCC	Power 3.3V+
3	SCL	Serial clock line
4	SDA	Serial data cable
5	RES	Display reset pin, low lever reset
6	DC	Register select pin (instruction/data register selection pin)
DC = ' 0' : Displaydata. (DC = ' 0' : Select command register) 
DC = ' 1 ' : Displaydata. (DC =, 1' : Select data register)
7	BLK	LCD backlight control, low level off backlight
8	MISO	Serial clock line
9	CS1	Display SPI chip selection
10	CS2	Touch screen SPI chip selection
11	PEN	Touch trigger output
12	NC	Hanging

To get started I'd just use software SPI so you can use whatever pins you want. Connect GND and VCC up to GND and 3.3v, then connect each pin to the easiest available IO pin.

In terms of the software, probably start out with the ST7735 and copy the code from https://www.espruino.com/ST7735

It should be pretty straightforward to map the pins given the data above, but any questions just ask :)

[espruino-discuss3]

Posted at 2020-07-10 by lloydwatkin

Thanks @gfwilliams! Will get back if (really "when") I'm stuck :)

[espruino-discuss3]

Posted at 2020-07-11 by @allObjects

The XPT2046 is the same as the ADS7843. What's making your situation a bit more complicated is that they both use the same SPI bus pin and control which chip is selected by CS1 and CS2 and the available modules do not use the CS1 and CS2 pins. So you have to merge the two modules into one and include the CS# control. The hardware I used expose the bus for each individual chip separately (see conversation about Modular and extensible UI framework and ui elements).