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Forum Index : Microcontroller and PC projects : Forget the ILI9488, The ST7796S is the new kid in town
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| matherp Guru  Joined: 11/12/2012 Location: United Kingdom Posts: 10083 |
Have a look The moire patterns are artifacts of the camera/screen combination This panel will be fully supported in V6.00.02RC23. It can work with the existing ILI9488 driver but anything involving reading the VRAM doesn't work. OPTION LCDPANEL ST7796S,orientation, DCpin, RESETpin, CSpin [,backlightpin] [,INVERT] It runs in RGB565 both on read and write so updates only take 2/3rds of the time of the ILI9488 and reads are much faster as the data rate doesn't need to be throttled like on the ILI9488 (and the ILI9341) The screen is 4" and nice and bright and it doesn't need any sort of H/W hack like the ILI9488 to work with touch and the SDcard. Implementation was reasonably easy except for one gotcha on switching from reading the on-board VRAM to writing it (as used in BLIT and transparent text). To do this I had include a delay until the next HSYNC otherwise the write was simply ignored. The display supports the new H/W scrolling in portrait mode. Edited 2025-05-07 22:26 by matherp |
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| ville56 Senior Member  Joined: 08/06/2022 Location: Austria Posts: 219 |
Peter, as far as I've seen therer are some variants on Aliexpress available that can be configured in 4 modes: SPI3, SPI4 wire, parallel 8 bit and 16 bit. Does it make sense/is it feasable, from your point of view, to also support the parallel modes? This would make a very powerful and flexible display for almost all purposes. Tnx for your work on MMBasic, Gerald 73 de OE1HGA, Gerald |
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stanleyella Guru Joined: 25/06/2022 Location: United Kingdom Posts: 2397 |
thanks Peter, checking prices now. using the ILI9488 (and the ILI9341) and diode resistor for reading sd card they are ok ST7796S not cheap... what is now? Edited 2025-05-08 01:47 by stanleyella |
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| dddns Guru Joined: 20/09/2024 Location: Germany Posts: 342 |
sounds amazing. Does it reach the ssd1963 in terms of responsiveness and scrolling e.g. in editor? Edited 2025-05-08 01:38 by dddns |
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| matherp Guru Joined: 11/12/2012 Location: United Kingdom Posts: 10083 |
Pretty much but only in portrait mode i.e 320x480. All of these smaller displays are organised that way. |
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Sasquatch Guru Joined: 08/05/2020 Location: United States Posts: 376 |
I see that the ST7796 displays are available with either resistive touch or capacitive touch using the FT6336 touch controller for a few $ more. My experience has been that in general the capacitive touch screens are usually more stable without the calibration offsets and drift that the resistive screens seem to have, although I have no direct experience with the FT6336 screens. On the other hand, the resistive touch controllers are more "mature" in terms of MMBasic use. Anyone have any thoughts or experience to share before I order a few panels? Edited 2025-05-08 04:36 by Sasquatch -Carl |
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| matherp Guru Joined: 11/12/2012 Location: United Kingdom Posts: 10083 |
Resistive touch seems to me to be more accurate. i.e. you can use a fine pointer whereas capacitive you need a finger or finger equivalent which tends to be chunky |
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| stanleyella Guru Joined: 25/06/2022 Location: United Kingdom Posts: 2397 |
I got the impression capacitive touch better, like phone screens but as said resistive ili works fine, thanks, I think stick with ili. tbo I like parking monitor with hdmi, vga, composite video £14 if they can make a 8" monitor why not just the screen? |
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| dddns Guru Joined: 20/09/2024 Location: Germany Posts: 342 |
A bit of a downside with portrait. The ssds seems to get dumped now and the IlI9488 was upgraded..IPS is coming but I think the controller chips will stay Many thanks for implementing, when I started with PicoMite this was not supported so I bought an ILI9341 but I would like to change it now to st7796 :) Edited 2025-05-09 03:25 by dddns |
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| matherp Guru Joined: 11/12/2012 Location: United Kingdom Posts: 10083 |
SSD is still my favourite and now we have the RP2350B it becomes more practical. The only trouble is that the panels tend to be expensive, looking on buydisplay.com, the cheapest one they have is the 4.3" 480x272 at USD31 with a touch chip |
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| dddns Guru Joined: 20/09/2024 Location: Germany Posts: 342 |
I just saw 7" for 26€, that why I've said on aliexpress. I'm not allowing cookies but they do tricks. I'm not sure but I've seen them go down now over weeks Edited 2025-05-09 03:44 by dddns |
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disco4now Guru Joined: 18/12/2014 Location: Australia Posts: 979 |
Peter, I have an ST7796S and have sort of got it going on the Armmite F4. I had to set the delay to switch back to Write mode to 5ms to get it to work. i.e. //#define ST7796Schangetowrite 1600 #define ST7796Schangetowrite 5000 Also BLIT READ and BLIT WRITE need a extra read in ReadBufferSPI before they work and the colour of WRITE copy is not quite correct. On a Picomite I had to recompile with the same changes to use any read operations. As a first step can you confirm this program behaves as expected on your ST7796S display. i.e. Transparent text,BLIT, BLIT READ/WRITE I will try and read out the ID of the display to see if yours is the same. Print "st7796S Test" CLS RGB(GREEN) Box 100,100,40,40,,RGB(RED),RGB(RED) Print Hex$(Pixel(1,1)) Blit READ 1,100,100,40,40 Blit WRITE 1,150,100,40,40 Blit 100,100,200,100,40,40 Print Hex$(Pixel(121,125)) Print Hex$(Pixel(171,125)) Print Hex$(Pixel(221,125)) Text 300,150,"HELLO" Text 300,100,"HELLO",,,,RGB(RED),-1 Timer =0 Box 0,0,10,10,1,RGB(red),RGB(red) Box 10,10,10,10,1,RGB(BLUE),RGB(BLUE) Print "WRITE TIME: ",Timer Timer =0 Blit 0,0,200,200,20,20 Print "BLIT TIME: ", Timer Timer =0 'CLS Print " CLS TIME: ",Timer Latest F4 Latest H7 FotS |
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| matherp Guru Joined: 11/12/2012 Location: United Kingdom Posts: 10083 |
The program worked perfectly for me. I did tune the wait down to the absolute minimum possible so it may need to be a bit more generous to cater for all controllers/wiring. What PicoMite version are you testing? Let me know and I'll post a more "relaxed" version |
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| disco4now Guru Joined: 18/12/2014 Location: Australia Posts: 979 |
Standard Picomite 2040 Latest F4 Latest H7 FotS |
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| matherp Guru Joined: 11/12/2012 Location: United Kingdom Posts: 10083 |
Try this PicoMite.zip If you can work out why the delay is needed at all it would be good  |
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