Go Down

Topic: MCUFRIEND_kbv Library for Uno 2.4, 2.8, 3.5, 3.6, 3.95 inch mcufriend Shields (Read 505989 times) previous topic - next topic

medpixman

Thank for getting back to me - the screen shows a very faint and low-contrast changing graphics display with overlying mostly white bars/stripes - that make the display unreadable.

The red board works. I think that the 2.4" TFT LCD (red board) has a ILI9340 controller with built in video RAM buffer.

I'm going to take your hint, that maybe there is a problem with the power from the 3.3v regulator on the Arduino. I'll try to measure the voltage to see if it drops.

david_prentice

Measure the current taken by the Uno + Blue Shield.   e.g. with a USB current meter

Or just feel the screen.  Does it get warm?

David.

medpixman

I haven't yet been able to measure the current, but the screen does get very warm. What does that mean?

david_prentice

It means that Mcufriend do not care what crap they sell.

It would make little difference to their production costs to replace HC245 with LVT245 or similar.
And a single series resistor to limit the backlight current.

Or even put a resistor pack with solder-bridges to configure for different panels.

David.

medpixman

Is there a work around? If I find a way to dim the backlight, might that solve the problem?

david_prentice

Your photo shows an SMD component near LCD_RD
The Banggood link does not show anything near LCD_RD legend.

Identify the SMD.   Is it a resistor?   What value?
Identify where it connects to.

Do you own a DMM ?
Or one of those dongles like #2851 ?

David.

smmofidi

Hi David
I bought 4 tft lcd 2.4 inch from 2 different stores

I used mcufriend_kbv and touch screen libraries to design

2 of them with ID = ili9325 works very well and has no problems...

but 2 other of them with ID = 0x6767 has image and unfortunately touch is not working
What should I do  to set up touch with id = 0x6767?

david_prentice

Read the how_to file e.g.
C:\Users\David Prentice\Documents\Arduino\libraries\Mcufriend_kbv\extras\mcufriend_how_to.txt

Code: [Select]
HX8367-A 240x320  ID=0x6767 #define SUPPORT_8347D


So you edit C:\Users\David Prentice\Documents\Arduino\libraries\Mcufriend_kbv\MCUFRIEND_kbv.cpp
and change
Code: [Select]
//#define SUPPORT_8347D             //HX8347-D, HX8347-G, HX8347-I, HX8367-A +520 bytes, 0.27s

to
Code: [Select]
#define SUPPORT_8347D             //HX8347-D, HX8347-G, HX8347-I, HX8367-A +520 bytes, 0.27s

smmofidi

I had made these changes before
the display works correctly
But Touch still doesn't work for id= 0x6767

When I run the  Arduino\libraries\MCUFRIEND_kbv\examples\diagnose_Touchpins
   it gives the following message:

Making all control and bus pins INPUT_PULLUP
Typical 30k Analog pullup with corresponding pin
would read low when digital is written LOW
e.g. reads ~25 for 300R X direction
e.g. reads ~30 for 500R Y direction

Testing : (A1, D6) = 31

david_prentice

Your Touch Panel is broken in the X direction.
Measure the resistance between LCD_RS and LCD_D7 with a DMM.

smmofidi

When the multimeter measures the resistance between pins (َ A1, D6) and touches the touch, the resistance changes...

But when I did the same for (A2, D7) the resistance between the pins (A2, D7) didn't change ...
The touch seems to be damaged...
Is it normal that touch of 2 tft's with ID = 0x6767 be damage?
Thank you very much for your guidance david...

david_prentice

When the multimeter measures the resistance between pins (َ A1, D6) and touches the touch, the resistance changes...

But when I did the same for (A2, D7) the resistance between the pins (A2, D7) didn't change ...
I would not expect the resistance to change.   The Shield is unplugged.
You have only got 2 wires from your DMM.
What is the resistance that you measured?  A1,D6 and A2,D7

It seems unlikely that two Shields are broken in the same way.
Does the glass look cracked?
Please report the resistances measured with your DMM for each shield.    Post the 0x9325 values too.

David.


smmofidi

the resistance between (A1,D6) for both of tft LCD's   with ID= 0x6767:    0.6 K ohm  constant

and the pins A2 and D7 are disconnected
touch should be damaged...



the resistance between (A1,D6) for  tft LCD   with ID= 0x9325 is variable 0.7 K  to 2.5 K ohm (when i touch different sections of tft)

the resistance between (A2,D7) for  tft LCD   with ID= 0x9325 is variable 0.7 K  to 2 K ohm (when i touch different sections of tft)



david_prentice

Your 0x6767 shields have probably got A1,D6 and A2,D7

Your 0x9325 shields almost certainly have got A1,D7 and A2,D6

I just measured an 0x1520 :
A1,D7 was 641R
A2,D6 was 399R

Please measure your 0x9325:
A1,D7 =
A2,D6 =

Please measure your 0x6767:
A1,D6 =
A2,D7 =

I wrote the diagnosis sketch because not everyone owns a DMM.

If you are clever enough,   you can place one probe on A2 and move the other probe from D2-D9
Observe any resistance.
Then repeat with fixed probe on A3 and D2-D9

David.

smmofidi

0x9325:

A1,D7= 0.5k ohm
A2 , D6= 0.6k ohm



0x6767:

 A1, D6= 0.61k       and A1 is disconnected to other LCD_Digital pins

A2, D7 = disconnected             A2,D6= 0.6 k ohm          A2 is just connected to  LCD_Digital(6) pins  and disconnected to others... 
 

Go Up