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Forum Index : Microcontroller and PC projects : Touch Screen - ST7789_300 on a breakout board - PIN HELP

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Askjerry
Newbie

Joined: 21/09/2025
Location: United States
Posts: 11
Posted: 04:31pm 21 Sep 2025
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I purchased a really nice breakout board on Amazon,
https://www.amazon.com/dp/B0C98G37PW

The board has a 420x320 color TFT... and I have most of the options figured out now.
WebMite MMBasic RP2350A Edition V6.00.03
OPTION SYSTEM SPI GP2,GP3,GP4
OPTION SYSTEM I2C GP8,GP9
OPTION FLASH SIZE 4194304
OPTION COLOURCODE ON
OPTION CPUSPEED (KHz) 150000
OPTION LCDPANEL ST7796S, LANDSCAPE,GP6,GP7,GP5

Written on the board are the pin assignments...
SCLK = GP2   CS = GP5
MOSI = GP3   DC = GP6
MISO = GP4   RST = GP7

IC2 =GP8, GP9

All the above I figured out... just two remaining... and I think they are for the touch screen...

TPRST = 10   TPLNT = 11

I just want to know the correct pins to type in OPTION TOUCH

I tried OPTION TOUCH GP10, GP11 then tried the GUI CALIBRATE, but not seeing any change when I put my finger on the target.

I tried OPTION TOUCH GP11, GP10 and again, no reaction to touching the target.

Of course after each failure... I have to clear the flash, then renter all the options again. (Not horrible, I copy from NOTEPAD++, click on TeraTerm, and Right-click to copy.) But... it's not working... any ideas???

(First post here... let's make it a head scratcher!)

THANKS in advance!!!
Jerry
 
matherp
Guru

Joined: 11/12/2012
Location: United Kingdom
Posts: 10533
Posted: 04:57pm 21 Sep 2025
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It uses a GT911 i2c capacititive touch controller. This is not supported by MMBasic - sorry.
 
Askjerry
Newbie

Joined: 21/09/2025
Location: United States
Posts: 11
Posted: 08:46pm 21 Sep 2025
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Well Phooey  

I guess I won't be able to use the interactive GUI components.

The breakout board has a JOYSTICK... if I can figure that out, it could be used to navigate a menu, and there are 2 buttons... I'll have to think about that.

Thanks for the quick reply,
Jerry
 
phil99

Guru

Joined: 11/02/2018
Location: Australia
Posts: 2787
Posted: 09:28pm 21 Sep 2025
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  Quote  Of course after each failure... I have to clear the flash, then renter all the options again.
Most Options can be individually removed with :-

OPTION xxx DISABLE

Leaving the rest intact.
 
Askjerry
Newbie

Joined: 21/09/2025
Location: United States
Posts: 11
Posted: 02:10am 22 Sep 2025
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Ok, nice and good to know... that way I don't have to keep restoring each one.

If anyone gets the same breakout board as me... this is what I have currently set...

WebMite MMBasic RP2350A Edition V6.00.03
OPTION SYSTEM SPI GP2,GP3,GP4
OPTION SYSTEM I2C GP8,GP9
OPTION FLASH SIZE 4194304
OPTION COLOURCODE ON
OPTION CONTINUATION LINES ON
OPTION CPUSPEED (KHz) 150000
OPTION LCDPANEL ST7796S, LANDSCAPE,GP6,GP7,GP5,,INVERT


It all seems to be working well.

This is the BREAKOUT BOARD that I got.
 
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