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Forum Index : Microcontroller and PC projects : MM+  ILI9488 LCD driver - orientation reversed?

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paceman
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Joined: 07/10/2011
Location: Australia
Posts: 1329
Posted: 12:32pm 16 Jan 2021
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I've just installed a 3.5" (480x320) ILI9488 LCD panel on PeterM's 'Universal Backpack' which uses the 64 pin MM+ with the 14 pin 'standard' SPI connector. The ILI9488 driver is one of the 'loadable' drivers developed by Peter and provided in Geoff's MMBasic Micromite V5.05.03 documentation.

The documentation gives the orientation parameters as: 1=landscape, 2=portrait, 3=reverse landscape and 4=reverse portrait. When I load the library with the 'landscape' parameter set to 1, it all works fine except that it displays 'landscape' upside down.

I changed the parameter to 3 and reloaded it. It again displayed in 'reverse landscape' which is correct as per the documentation.

Anyone else had this problem or am I stuffing something up.

Greg
 
paceman
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Joined: 07/10/2011
Location: Australia
Posts: 1329
Posted: 04:43am 17 Jan 2021
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Well this is getting stranger. I left the screen running last night with the orientation parameter still set at 3, i.e. correctly showing inverse landscape. I then sat down to check out the forum and turned the power off the screen/backpack.

I've just now turned it back on again and lo... it is now displaying normal 'correct way up' landscape. The library driver is still presumably holding the '3' orientation parameter.

Ideas anyone?

Greg
 
JohnS
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Joined: 18/11/2011
Location: United Kingdom
Posts: 4147
Posted: 04:30pm 17 Jan 2021
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Dubious connection somewhere?

John
 
OA47

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Joined: 11/04/2012
Location: Australia
Posts: 1013
Posted: 12:59am 18 Jan 2021
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Greg, I have had inconsistent lcd panel moments with the F4 units running 5.5.10, where when I set option lcdpanel ili9341, l and option touch 51,34 the text on screen is shown inverted but the touch is not inverted. Have tried cleaning up the power supply to no avail. May have to re-flash and report back.

OA47
 
paceman
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Joined: 07/10/2011
Location: Australia
Posts: 1329
Posted: 11:21am 18 Jan 2021
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Hi Graeme,
Hmmm.. I've never used the F4 units so obviously never seen that. Maybe in that case the touch controller was initialised but not the panel.

I'm thinking that my problem might be the issue that Peter found with the ILI9488 display:
Touch and the SDcard share the SPI port with the display. I found that the SDO(MISO) pin on the display (SPI input from the display to the Micromite) interfered with the SD_MISO and T_DO pins even though the display wasn't selected (CS high). This could be fixed by connecting SDO(MISO) to the Micromite through a 680ohm resistor - very strange.

Geoff's documentation for the ILI9488 driver says that MISO should not be connected and that that pin should be clipped off. I haven't done that (yet) because I'm not sure of how it will effect (or not) the touch and SD card. I might even have a go at cutting the track on Peter's board and trying to organise a jumper there to insert an SMD 680 ohm resistor like he mentioned above. It's a pretty busy board though so not sure I'll be able to.

John suggested a possible iffy connection but I don't think that's the case because I do occasionally swap displays on this board and haven't had this issue with any other displays.

Greg
 
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