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Forum Index : Microcontroller and PC projects : Practical Electronics PicoMite display problems

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pepperm
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Joined: 14/11/2022
Location: United Kingdom
Posts: 7
Posted: 02:16pm 17 Nov 2022
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Hi

I'm following the PicoMite articles in Practical Electronics (Aug 2022 UK) and am working with the Waveshare Pico-Res Touch 2.8 and 3.5inch LCD modules and am having two different problems with "PicoMite MMBasic Version 5.07.05RC9".

With the 2.8 inch display, everything seems to work except that when I come to run "gui test lcdpanel", the test display works initially but then when I returnto the project a few hours later, the test just runs for about 2 seconds then the display never shows anything else.

With the 3.5 inch display, I just cant access the SD card and just get an "Error : SD Card not found" error.

For both displays I have followed, many times all the suggested config options, and show the results of "Option List" for the 3.5 inch display below.

So, has anyone else followed the worked examples and got them to work completelt, as I haven't or can anyone suggest why I am having these problems please?

3.5" module config:
PicoMite MMBasic Version 5.07.05RC9
OPTION SYSTEM SPI GP10,GP11,GP12
OPTION SYSTEM I2C GP20,GP21
OPTION CPUSPEED (KHz) 252000
OPTION LCDPANEL ILI9488W, RLANDSCAPE,GP8,GP15,GP9
OPTION TOUCH GP16,GP17
GUI CALIBRATE 1, 1113, 499, -4042, -104000
OPTION SDCARD GP22, GP5, GP18, GP19
OPTION RTC AUTO ENABLE


Mark
 
matherp
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Joined: 11/12/2012
Location: United Kingdom
Posts: 6619
Posted: 02:37pm 17 Nov 2022
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3.5" sdcard should just be OPTION SDCARD GP22. It shares SPI with the display. If the article says otherwise it is wrong.

You should also add GP13 to the set up of both displays. This controls the LCD backlight. It is possible that this is the problem with the 2.8" display.

OPTION LCDPANEL st7789_320, LANDSCAPE,GP8,GP15,GP9,gp13
Edited 2022-11-18 00:41 by matherp
 
pepperm
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Joined: 14/11/2022
Location: United Kingdom
Posts: 7
Posted: 07:46pm 17 Nov 2022
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Thanks, it does say those things in the article but I'll give your suggestions a go when I get home.
 
pepperm
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Joined: 14/11/2022
Location: United Kingdom
Posts: 7
Posted: 09:43am 18 Nov 2022
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Right... I have now configured the Picos with the following PicoMite setups (put here just in case anyone else wants to know) and can confirm that the setup for the SD card in PE Aug 2022 for the 3.5" display are wrong. "OPTION SDCARD GP22" sorts it out compared to what is printed in the magazine.

However, I still have the same problem with the 2.8" display in that when I initially configure everything the "gui test lcdpanel" command works as expected (losts of coloured circles in the display). The trouble is that if I unplug the Pico and restart, then issue the "gui test lcdpanel" command the display kicks into life for 1-2 seconds then goes blank. Further tests are just met with a blank screen. I have even tried programatically (with the RTCdemo.txt program mentioned in the article) displaying things but this still results in a blank screen.

I thought initially that the 2.8" display was just faulty, but if I tear everything down and rebuild and reconfigure, I get the same operation, be it short term.

Any ideas?

Here are the configs:

"Waveshare Pico-ResTouch-LCD-2.8" from PE aug 2022
Option reset
option list
option cpuspeed 252000
option system spi GP10, GP11, GP12
option lcdpanel st7789_320, l, gp8, gp15, gp9, gp13
gui test lcd panel
option touch gp16, gp17
gui calibrate
gui test touch
option sdcard gp22
files
option system i2c gp20, gp21
rtc settime 22,11,18,10,00,00
option rtc auto enable
print time$
print date$
option list

"Waveshare Pico-ResTouch-LCD-3.5" from PE aug 2022
Option reset
option list - confirm empty
option cpuspeed 252000
option system spi GP10, GP11, GP12
option lcdpanel ili9488w, rl, gp8, gp15, gp9, gp13
gui test lcd panel
option touch gp16, gp17
gui calibrate
gui test touch
option sdcard gp22
files
option system i2c gp20, gp21
rtc settime 22,11,18,10,00,00
option rtc auto enable
print time$
print date$
option list
 
matherp
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Joined: 11/12/2012
Location: United Kingdom
Posts: 6619
Posted: 09:56am 18 Nov 2022
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Lots of people use that display and no-one has raised the issue before so there must be something strange going on - dry joint or similar. I've just replicated your exact setting and it works fine each and every time
 
pepperm
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Joined: 14/11/2022
Location: United Kingdom
Posts: 7
Posted: 10:08am 18 Nov 2022
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Thanks for the duplicating, I presume with the 2.8" didplay. I guess that means that the display is faulty. I'll resolder the joints.

Thanks.
 
Pluto
Senior Member

Joined: 09/06/2017
Location: Finland
Posts: 108
Posted: 10:55am 18 Nov 2022
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Please note that ILI9488 problems have been reported earlier on the forum.
If I remember correctly, thera were several solutions:
-cut the MISO connection,
-install a resistor in the MISO line, or
-install a transistor in the MISO line
 
matherp
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Joined: 11/12/2012
Location: United Kingdom
Posts: 6619
Posted: 10:56am 18 Nov 2022
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  Quote  Please note that ILI9488 problems have been reported earlier on the forum.


Not relevant to the Waveshare version which doesn't expose MISO
 
Pluto
Senior Member

Joined: 09/06/2017
Location: Finland
Posts: 108
Posted: 11:17am 18 Nov 2022
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Practical Electronics instruction for ILI9488W:
  Quote  10. OPTION SDCARD GP22, GP5, GP18, GP19 (configure
SD socket – note: we need to define the SPI pins with this
display module)


If I understand this correctly, the display and SD-card will use different SPIs.

Could you try again with your original option settings

  Quote  3.5" module config:
PicoMite MMBasic Version 5.07.05RC9
OPTION SYSTEM SPI GP10,GP11,GP12
OPTION SYSTEM I2C GP20,GP21
OPTION CPUSPEED (KHz) 252000
OPTION LCDPANEL ILI9488W, RLANDSCAPE,GP8,GP15,GP9
OPTION TOUCH GP16,GP17
GUI CALIBRATE 1, 1113, 499, -4042, -104000
OPTION SDCARD GP22, GP5, GP18, GP19
OPTION RTC AUTO ENABLE


But correct the LCDPANEL line to include the GP13 (as in the PE article):
  Quote  OPTION LCDPANEL ILI9488W, RL, GP8, GP15, GP9, GP13
 
pepperm
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Joined: 14/11/2022
Location: United Kingdom
Posts: 7
Posted: 11:18am 18 Nov 2022
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Resoldering has changed nothing. Maybe I'll order a new display and see how that works. or not.

It is very odd that if I just restart everything config wise after maybe a day of powerdown, everything works and works for hours, all until I power down then power back up again... very odd behaviour.
 
matherp
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Joined: 11/12/2012
Location: United Kingdom
Posts: 6619
Posted: 11:20am 18 Nov 2022
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  Quote  If I understand this correctly, the display and SD-card will use different SPIs.

Could you try again with your original option settings


This is pointless as it is wrong. I have the display. I developed the driver on it. I tested it and the correct settings are as the OP posted in his revised version following my advice. It is how the display is wired.
 
pepperm
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Joined: 14/11/2022
Location: United Kingdom
Posts: 7
Posted: 11:20am 18 Nov 2022
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Hi

This config is for the 3.5" display, that does work. It is the 2.8" display that has a problem.

The 2.8" display used a st7789_320.

But correct the LCDPANEL line to include the GP13 (as in the PE article):
  Quote  OPTION LCDPANEL ILI9488W, RL, GP8, GP15, GP9, GP13
 
pepperm
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Joined: 14/11/2022
Location: United Kingdom
Posts: 7
Posted: 05:07pm 26 Nov 2022
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Well, I got the 3.5" version working as expected with the config changes, but the 2.8" version still blanks the display after about a second when using it beyond a repower or something.

As it happened I replaced the touch controller on the board and noticed that when it was removed (to be used in the 3.5" display that I blew up - dont ask) the display worked repeatedly without a problem.

The replacement 2.8" display is still in transit so will see if I get the same behaviour with that unit.
 
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