no inverted lcd backlight

[SvenMb]

Hi,

I use ESP32 on AZ-Touch display and ESP32 2432S028 with LVGL and HASPMOTA.

Both model use a inverted BACKLIGHT (means L = on, H = off), but there is no BACKLIGHT_i or alike.

Is there any way to acomplish the same and work together with the new auto-dimm function in HASPMOTA?

Sven

[s-hadinger]

Not that I can think of. This seems to be the first time we see an inverted backlight. I guess we would need to add it.
Or if someone has a work around in mind?

[SvenMb]

this is the schematic for the backlight

I can not get :b 1 or :b,1 to change anything, I am using the universal driver and added it in the display.ini Do I need something else?

[SvenMb]

To clear this up, on this ESP32 2432S028 there is NO inverted backlight, switching off backlight just didn't work, so I got a white screen when it should go off... my fault in analysing the problem.

If you search for inverted backlight, the answer from gemu2015 with 'b,01' in display.ini is what you search for. In documentation they call it inverted backpanel, therefor I couldn't find it.

[gemu2015]

there is an option to invert back panel in display descriptor:
:b 1

[SvenMb]

I can not get :b 1 or :b,1 to change anything, I am using the universal driver and added it in the display.ini Do I need something else?

:H,ST7789,320,240,16,SPI,1,*,*,*,*,*,*,*,40
:S,2,1,1,0,80,30
:I
01,A0
11,A0
3A,81,55
36,81,00
21,80
13,80
29,A0
:o,28
:O,29
:A,2A,2B,2C
:R,36
:0,A0,00,00,00
:1,00,00,00,01
:2,60,00,00,02
:3,C0,00,00,03
:i,20,21
:b,01
:D,50
:M,3795,214,3907,281
:UTI,XPT2046,S2,33,*,*
CPR 00
RT
:UTT
XPT 300
RT
:UTX
MV 0 2
RT
:UTY
MV 2 2
RT
#

[gemu2015]

there has been a large rework lately and the backlight function seems to be broken on SPI displays.
if you compile yourself exchange this file and report
uDisplay_SPI_panel.cpp.zip

[SvenMb]

Just tried to set GPIO21 from BACKLIGHT to LED and then it worked correctly with my display.ini, very strange.

Will try with self compiled binary... better use release or development branch?

[SvenMb]

there has been a large rework lately and the backlight function seems to be broken on SPI displays. if you compile yourself exchange this file and report uDisplay_SPI_panel.cpp.zip

Yes that change reenables the GPIO code for the backlight, but there musst be something else wrong, since I had to fix the GPIO# in code to get it working... (also the build system is fighting against me, since sometimes I get a cached uDisplay driver while building, which makes everything more difficult, but thats just because I am inexperienced here)

[SvenMb]

small extra problem... while my CYD (2432S028v3)is working with #24278, the AZ-Touch-MOD does not accept PWM modulation for backlight well. If I change that backlight to PWM_i I can control it perfectly, so I am lost again...

Also if I change the source to apply digital on/off to backlight, like the esp8266 does, then it also works perfect.

So I ask, if it is possible to make the PWM control for ESP32 backlights optional? mayby another SetOption?

[gemu2015]

i am currently testing all my displays with the new driver and found several other issues.
i will add the requested option and make a pr in a few days.

[gemu2015]

ok exchange the udisplay folder and test.
:b,02 disables PWM
UDisplay.zip

[SvenMb]

So I realize, I have to use ':b,03' for nopwm and inverted...

but unfortunately it does not work, panel itself doesn't show anything anymore, but backlight for this setting works as it should.

:H,ILI9341,240,320,16,SPI,1,*,*,*,*,15,*,*,40
:S,2,1,1,0,40,20
:I
EF,3,03,80,02
CF,3,00,C1,30
ED,4,64,03,12,81
E8,3,85,00,78
CB,5,39,2C,00,34,02
F7,1,20
EA,2,00,00
C0,1,23
C1,1,10
C5,2,3e,28
C7,1,86
36,1,48
37,1,00
3A,1,55
B1,2,00,18
B6,3,08,82,27
F2,1,00
26,1,01
E0,0F,0F,31,2B,0C,0E,08,4E,F1,37,07,10,03,0E,09,00
E1,0F,00,0E,14,03,11,07,31,C1,48,08,0F,0C,31,36,0F
11,80
29,80
:o,28
:O,29
:A,2A,2B,2C,16
:R,36
:0,48,00,00,01
:1,28,00,00,02
:2,88,00,00,03
:3,E8,00,00,00
:i,20,21
:b,03
:r,2
:UTI,XPT2046,S1,*,*,*
CPR 00
RT
:UTT
XPT 300
RT
:UTX
MV 0 2
SCL 460 0.0930233
LIM 319
RT
:UTY
MV 2 2
SCL 300 0.0695652
LIM 239
RT
#

[gemu2015]

ok, try to also replace renderer folder.
Display_Renderer-gemu-1.0.zip

[SvenMb]

Works on the AZ-Touch-Mod now. will test later on the ESP32-2432S028v3 with PWM.... tested now, also works there.