TheBackShed.com

Forum Index : Microcontroller and PC projects : Waveshare 3.5" ILI9488W Touch Screen Splatter

Author

Message

Bowden_P
Senior Member

Joined: 20/03/2019
Location: United Kingdom
Posts: 162

Posted: 05:23pm 09 Mar 2023

Copy link to clipboard

Print this post

Hi,
I have 2 standard PicoMites connected to these screens with :-

> option list
PicoMite MMBasic Version 5.07.07b24
OPTION SYSTEM SPI GP10,GP11,GP12
OPTION SYSTEM I2C GP20,GP21
OPTION COLOURCODE ON
OPTION CPUSPEED (KHz) 130000
OPTION LCDPANEL ILI9488W, RLANDSCAPE,GP8,GP15,GP9,GP13
OPTION GUI CONTROLS 1
OPTION TOUCH GP16,GP17
GUI CALIBRATE 0, 233, 3882, 1275, -866
OPTION SDCARD GP22, GP5, GP18, GP19
OPTION RTC AUTO ENABLE
>

Both exhibit screen splatter when the "GUI TEST TOUCH" test is run.
This is a typical result when making a 7 x 5 array of touched points :-

Most - but not all - of the rogue pixels appear on the touch release.
Repeating "GUI CALIBRATE" doesn't appear to change this.

If I run this code :-

' Touch screen test.
' =================
' Provides 3 x 3 pixel plots under the touch point.

OPTION EXPLICIT
OPTION DEFAULT NONE
dim x%,y%,i%,j%

'SETPIN GP17, INTL, Touch_Int ' Use this if "OPTION GUI Controls" is zero.
gui interrupt Touch_Int

cls
DO : LOOP

SUB Touch_Int
x%=TOUCH(X):y%=TOUCH(Y)
for i%=-1 to 1
for j%=-1 to 1
pixel x%+i%,y%+j%
next j%
next i%
END SUB

I get this result :-

Just wondering if my screens are at fault. Has anyone else seen this ?

With best regards, Paul.

p.s. Sorry about the picture quality.

Nothing so constant as change.

matherp
Guru

Joined: 11/12/2012
Location: United Kingdom
Posts: 10633

Posted: 05:33pm 09 Mar 2023

Copy link to clipboard

Print this post

Not sure what the issue is. Your test looks pretty much perfect. GUI TEST TOUCH doesn't purport to be anything more than a very simple test that touch is working and the line tracks the stylus when it is kept in contact and moved. It does not do anything to remove release artefacts

Bowden_P
Senior Member

Joined: 20/03/2019
Location: United Kingdom
Posts: 162

Posted: 06:08pm 09 Mar 2023

Copy link to clipboard

Print this post

Hi Peter,
When I have used GUI TEST TOUCH before it has given a reasonably clean response to single touches, and also good at line drawing. For this screen single touches come out as a bit of a mess! ( Hence my screen query.)

I am experimenting with controlling frequency and output level of an oscillator using 2 slider-like graphics, but the jitter I get is causing very erratic behaviour, akin to the GUI TEST TOUCH response. ( I also hope to use some Advanced Graphics features.)

I have based these graphics on one used in a previous project using a Micromite v2 to control a servo, which worked very successfully, so hoped to do the same here.

With best regards, Paul.
Edited 2023-03-10 04:11 by Bowden_P

Nothing so constant as change.

matherp
Guru

Joined: 11/12/2012
Location: United Kingdom
Posts: 10633

Posted: 06:58pm 09 Mar 2023

Copy link to clipboard

Print this post

Please try the attached and let me know if better

PicoMite.zip

Bowden_P
Senior Member

Joined: 20/03/2019
Location: United Kingdom
Posts: 162

Posted: 08:35pm 09 Mar 2023

Copy link to clipboard

Print this post

Hi Peter,
Wow - that's quite an improvement, as below!!

Thank you very much! There are 5 points showing a second point plotted, but they are nevertheless very close to the original.

I have also tried my slider graphics, which now work very much better too!

May I ask what the fix was?

With best regards, Paul.
p.s. Again I'm struggling with the camera.
Edited 2023-03-10 06:36 by Bowden_P

Nothing so constant as change.

Print this page

To reply to this topic, you need to log in.