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Forum Index : Microcontroller and PC projects : ILI9481 IPS on PicoMite
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bigmik Guru  Joined: 20/06/2011 Location: AustraliaPosts: 2870 |
Good Morning/Evening Peter, All, That latest version is faster than the last one, but still a bit slow, I can confirm the Target circles are now white and all seems to look as expected. I did cls in various colours and noticed a (very) slight beat/strobe effect in PINK and Brown. If it wasnt for the full screen of colour I doubt you would see it. The strobing doesn't occur with Red, Blue, yellow, cyan, magenta and green. They are as pure as one could expect. Pink and Brown are pure on the ILI9488 display so i doubt it is my power supply. You have done very well without having a display to play with yourself. I will be chasing little white balls around a golf course this morning so I can try this afternoon if you wish. Regards, Mick EDIT** Of course the strobe effect could be a characteristic of this particular display, and in all honesty it is very hard to see, it is only I got close to check for missing lines etc. if this Cannot be fixed it isn’t a real problem IMHO Mg Edited 2022-06-30 08:32 by bigmik Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<< |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 8592 |
Mick I've speeded up SPI to the same as ILI9488/ILI9341 in this version. The reason I've been cautious on this while we get it working is web reports that the ILI9481 chip is sensitive to SPI speeds but who knows? Any luck with reading pixels/blit with this version? PicoMite.zip |
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| bigmik Guru Joined: 20/06/2011 Location: AustraliaPosts: 2870 |
Sorry Peter, That version doesn’t seem to initialise at all, it is permanently black screen with or without MISO Mick Ps I might not be able to check versions as often as last night. Mg Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<< |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 8592 |
Slowed SPI down to 16MHz PicoMite.zip |
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| bigmik Guru Joined: 20/06/2011 Location: AustraliaPosts: 2870 |
G’day Peter, That one works fairly well, however the pixel read back doesn’t work Speed seems a little slow but not overly so. When I can get a few minutes I will check cls fills with the ILI9488 Mick Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<< |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 8592 |
try 20mhz PicoMite.zip NB: this display is operating in RGB666 not RGB565. This needs 3 bytes per pixel rather than 2 which has an impact on speed. When I get my display I'll see if I can get RGB565 running. The early trials I did with you that didn't work were RGB565 so this will need more work than we can do online |
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| bigmik Guru Joined: 20/06/2011 Location: AustraliaPosts: 2870 |
Hi Peter, That still works, I compared the cls speed to the ili9488 and I think it is marginally slower but probably not enough to cause any issue, it is just a guess but I would think the speed is about 20% slower. I am wondering if we use 2 resistors (say 470R) and put one in series with the Miso of the touch and miso of the tft and then maybe touch and tft read can both be possible Mick Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<< |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 8592 |
Mick If touch is working with the display MISO connected then there is nothing wrong with the electronics. The issue is the code for reading the framebuffer. I'll look at that once I get a display. ILI9488 runs at 25MHz SPI. This one seems to max at 20MHz - you reported fail at 25MHz |
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| bigmik Guru Joined: 20/06/2011 Location: AustraliaPosts: 2870 |
Peter, I guessed the speed was 20% slower so I think that is not too bad in the scheme of things, these displays are supposed to be daylight readable. There is not much sun here at the moment but if they are then using them outdoors could be a very real option. I am happy if you want to test speeds between 20 and 25 but I am also mindful that that other displays may not be identical on maximum SPI speed. I am also happy if and when you want to try other changes. I appreciate it isnt the same as testing it on your own module. Regards, Mick Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<< |
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