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v.lenzer
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Joined: 04/05/2024
Location: Germany
Posts: 68

Posted: 10:29pm 04 Dec 2025

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My new project, "Human Radar" (https://www.thebackshed.com/forum/ViewTopic.php?FID=16&TID=18438), uses a 320x240 ILI9341 display.

With these options:

PicoMite MMBasic RP2040 Edition V6.00.03

OPTION SYSTEM SPI GP6, GP3, GP4

OPTION AUTORUN ON

OPTION COLOURCODE ON

OPTION CPUSPEED (KHz) 200000

OPTION LCDPANEL ILI9341, LANDSCAPE, GP7, GP2, GP5
everything works perfectly.

Now I've bought four more displays from AliExpress, which also use the ILI9341 display driver. They look like the display I'm currently using. However, it appears they're using portrait mode, even though landscape is selected. The small red dot on the left side of the display in the radar grid isn't red, as it should be, but blue.

I've tried all the available settings for the ILI9341 (L, P, RL, RP). The display rotates, but it's not using the full 320 x 240 pixels. It looks like it's using 0-240 for X and 0-320 for Y.

Does anyone have any suggestions on how I can use this display with a different setting?

Best wishes! Joachim

v.lenzer
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Joined: 04/05/2024
Location: Germany
Posts: 68

Posted: 10:37pm 04 Dec 2025

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Backside of the "good" ones.

Backside of the "bad" ones.

Edited 2025-12-05 08:41 by v.lenzer

Best wishes! Joachim

disco4now

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Joined: 18/12/2014
Location: Australia
Posts: 1067

Posted: 11:01pm 04 Dec 2025

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The Red/Blue reversal should be fixed by using the INVERT parameter when the display is setup.
OPTION LCDPANEL .................,INVERT

You can adjust the driver setting after it initiates using
POKE DISPLAY command [,data1]
command &H36 is the likely area you need to adjust. e.g.
POKE DISPLAY &H36,xx

This from the source might help help working out how to swap Landscape/Portrait after it is loaded.

#define ILI9341_MEMCONTROL 0x36
#define ILI9341_MADCTL_MY 0x80
#define ILI9341_MADCTL_MX 0x40
#define ILI9341_MADCTL_MV 0x20
#define ILI9341_MADCTL_ML 0x10
#define ILI9341_MADCTL_RGB 0x00
#define ILI9341_MADCTL_BGR 0x08
#define ILI9341_MADCTL_MH 0x04

// ILI9341 Orientation Modes
#define ILI9341_Portrait (ILI9341_MADCTL_MX | ILI9341_MADCTL_BGR)
#define ILI9341_Portrait180 (ILI9341_MADCTL_MY | ILI9341_MADCTL_BGR)
#define ILI9341_Landscape (ILI9341_MADCTL_MV | ILI9341_MADCTL_BGR)
#define ILI9341_Landscape180 (ILI9341_MADCTL_MY | ILI9341_MADCTL_MX | ILI9341_MADCTL_MV | ILI9341_MADCTL_BGR)

F4 H7 FotS F4xGT

Volhout
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Joined: 05/03/2018
Location: Netherlands
Posts: 5512

Posted: 08:25am 05 Dec 2025

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Hi Joachim,

Once you defined the correct settings, could you please share these. I also have some 2.4" on order, and fear the same issue.

Thank you

Volhout

PicomiteVGA PETSCII ROBOTS

v.lenzer
Regular Member

Joined: 04/05/2024
Location: Germany
Posts: 68

Posted: 12:47pm 05 Dec 2025

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Thank you for the information. I managed to make the display now look the same as the other displays. When setting the option for the LCD, I entered "RP" as the orientation and in the program
poke display hres 320
poke display vres 240
When I want to append "INVERT" to the LCD OPTION, I get an error (PIN 0/NULL). It worked with a fantasy GPIO, but all colors were inverted. The blue dot became yellow and the actually correct green lines were also inverted. But you can set that with LINE and CIRCLE. That's not a problem.

PicoMite MMBasic RP2040 Edition V6.00.03
OPTION SYSTEM SPI GP6,GP3,GP4
OPTION COLOURCODE ON
OPTION CPUSPEED (KHz) 200000
OPTION LCDPANEL ILI9341, RPORTRAIT,GP7,GP2,GP5
Edited 2025-12-05 22:53 by v.lenzer

Best wishes! Joachim

matherp
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Joined: 11/12/2012
Location: United Kingdom
Posts: 10671

Posted: 02:16pm 05 Dec 2025

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Quote When I want to append "INVERT" to the LCD OPTION, I get an error (PIN 0/NULL).

The first optional parameter is a pin for the backlight. The second is the invert option. Just use ,,INVERT

HOWEVER
invert won't do what you want as it makes black white.

Try using bit 3 in register &H36
#define ILI9341_MADCTL_BGR 0x08

ville56
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Joined: 08/06/2022
Location: Austria
Posts: 302

Posted: 04:10pm 05 Dec 2025

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I found this type of color errors typically on IPS displays and the INVERT parameter cured it. Had this also when I retrofitted a TFT display with an IPS panel.

Gerald

73 de OE1HGA, Gerald

matherp
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Joined: 11/12/2012
Location: United Kingdom
Posts: 10671

Posted: 04:24pm 05 Dec 2025

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As in my reply above, invert is different to a simple B/R swap.IPS displays without invert set see a value of 0 as full on and 255 is off for each of R G and B.
The OP is not seeing an inverted display just a R B swap. The control for this in a ILI9341 is bit 3 of register &H36

v.lenzer
Regular Member

Joined: 04/05/2024
Location: Germany
Posts: 68

Posted: 09:42pm 05 Dec 2025

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I must confess that I don't quite understand what I'm supposed to try. I can't make heads or tails of `#define`. I'm more of an assembly language person. I'm programming the RP2040 using MMEdit and I am trying to understand MMBasic in this way. If you could tell me what to enter, either on the console or in MMEdit, that would be a huge help. I'm sure we can get somewhere that way. It would be good for the future, since there are obviously other ILI9341 displays out there that are different.

And indeed, INVERT inverts all colors. In my case, the black background becomes white, the green mesh is somehow pink, and the dot is yellow. I was able to enter the inverted LCD option with two commas. I hadn't thought of that.
Edited 2025-12-06 07:43 by v.lenzer

Best wishes! Joachim

disco4now

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Joined: 18/12/2014
Location: Australia
Posts: 1067

Posted: 10:16pm 05 Dec 2025

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So "RP" is now setting &H36 as 0x88 , if we don't want Bit3 then try

POKE DISPLAY &H36,0x80 or
POKE DISPLAY &H36,0x88 if we have it the wrong way.
and then your
poke display hres 320
poke display vres 240

F4 H7 FotS F4xGT

v.lenzer
Regular Member

Joined: 04/05/2024
Location: Germany
Posts: 68

Posted: 10:18pm 05 Dec 2025

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Following a tip I found online that AliExpress was selling displays with the wrong driver (for example here https://lecity.edu.au/?p=2761), I entered this option:
`OPTION LCDPANEL ST7789, LANDSCAPE,GP7,GP2,GP5,,INVERT`. Now all the colors are correct!

Together with `poke display hres 320` and `poke display vres 240`, the orientation is also correct.
Edited 2025-12-06 08:31 by v.lenzer

Best wishes! Joachim

phil99

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Joined: 11/02/2018
Location: Australia
Posts: 2848

Posted: 10:20pm 05 Dec 2025

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A bit of trial and error using the information from Peter and disco4now was able to swap red and blue on a normal ILI9341. However this also created the same problem you had with vertical and horizontal. Using your cure for that restored things.

Give this a try.

> poke display &H36, &H03
> cls rgb(blue)
> cls rgb(red)
> poke display hres 320
> poke display vres 240
> cls rgb(blue)
> cls rgb(red)
> poke display hres 240
> poke display vres 320
> cls rgb(blue)
> cls rgb(red)
>

PS. Poke Display &H36, &H00 returned the display to original settings.
Edited 2025-12-06 08:28 by phil99

v.lenzer
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Joined: 04/05/2024
Location: Germany
Posts: 68

Posted: 11:24pm 05 Dec 2025

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Thank you so much for your message, phil99! That's helpful.

My options:

> option list
PicoMite MMBasic RP2040 Edition V6.00.03
OPTION SYSTEM SPI GP6,GP3,GP4
OPTION COLOURCODE ON
OPTION CPUSPEED (KHz) 200000
OPTION LCDPANEL ILI9341, RPORTRAIT,GP7,GP2,GP5

I tested with these lines:

poke display &H36, &H03
cls rgb(blue)
cls rgb(red)
poke display hres 320
poke display vres 240

This solved the color problem. BUT: now X0/Y0 is no longer in the upper left corner, but in the upper right corner. I don't understand it, but that's how it is.

This is the entire program. Please note that this was only intended to help understanding the graphics commands. It has nothing to do with the radar program. I think there's a simpler way to convert from polar coordinates to Cartesian coordinates.
... 'Hires tests
'Display of the display and font parameters
'print "Vertical resolution :";mm.vres
'print "Horizontal resolution :";mm.hres
'print "Font height :";mm.info(fontheight)
'print "Font width ;";mm.info(fontwidth)
'
'Drawing commands:

'poke display hres 320
'poke display vres 240

poke display &H36, &H03
cls rgb(blue)
cls rgb(red)
poke display hres 320
poke display vres 240
'cls rgb(blue)
'cls rgb(red)
'poke display hres 240
'poke display vres 320
'cls rgb(blue)
'cls rgb(red)

midx=160' x-center
midy=240 'y-center
netr=50' element length arc radius
startw=22.5' start angle
arcw=135' arc angle

for i=0 to 90
radar_net
r=200
w=i
w=(w*pi)/180
x2=r*cos(w)
y2=r*sin(w)
'print "X2:"x2;" Y2:";y2;" W:";w

circle x2,y2,6,,1,rgb(red),rgb(red)
break 100

next i

end

sub radar_net

cls

arc 160,240,60,,285,75,rgb(green)

arc 160,240,120,,285,75,rgb(green)

arc 160,240,180,,298,62,rgb(green)

arc 160,240,240,,318,42,rgb(green)

line 0,0,160,240,,rgb(green)

line 160,0,160,240,,rgb(green)

line 320,0,160,240,,rgb(green)

line 0,150,160,240,,rgb(green)

line 320,150,160,240,,rgb(green)

end sub

It is now after midnight in Germany. All I can see before my burning eyes is "OPTION LCDPANEL DISABLE". I'll continue tomorrow :)
Edited 2025-12-06 09:25 by v.lenzer

Best wishes! Joachim

TassyJim

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Joined: 07/08/2011
Location: Australia
Posts: 6381

Posted: 12:08am 06 Dec 2025

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disco4now said So "RP" is now setting &H36 as 0x88 , if we don't want Bit3 then try

POKE DISPLAY &H36,0x80 or
POKE DISPLAY &H36,0x88 if we have it the wrong way.
and then your
poke display hres 320
poke display vres 240

I think that you need
POKE DISPLAY &H36,0x80

It is bit 3 (decimal 8) not decimal 3 and you need bit 3 set to 0 leaving the other bits set as required for display orientation.

Jim

VK7JH
MMedit

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