flickering STM32 touch screen

[achillis1]

Hello

I have flowcode 8 and trying to program an STM32F449I - discovery mcu with touchcreen

I have selected the board in flowcode8 and try to print a number. If the number printing is within a loop then the screen flickers and the printing is distorted. If I add 1 second delay then at each printing the screen flickers and the number is being dragged along the X axis and then stabilizes until the next printing. The only way not to have this issue is to have 5 seconds delay which off course messes up the whole routine. At first I though that this was cause by the "clear display" but I get the same fault even without that. My code will be used to take a value ( by a touch update or via external input) and continuously update my text box or any other indicator I would add.
I read that this might be cause because the MCU uses the same buffer to read data and then print. Would be there any workaround via the flowcode settings and components?

I will attach my code. It is not the intended final one but a test one to check the MCU's capabilities and flowcode's bugs.

[medelec35]

Hello Rather than using ClearDispaly and PrintNumber, what about just use the Print function that prints strings.
You can use use a calculation Icon with:

Code: Select all

NumberString = ToString$(number)
NumberString = NumberString + "    "

Print NumberString
The + " " clears unwanted digits.

[achillis1]

it is still the same thing!
every time when the screen will display anything, all items on the screen travel rightwards and then fall into place
I am trying to use toughGFx to make a test program but I still havent managed succesfully to operate their software

[LeighM]

Strange that the longer delay fixes the issue.
The Flowcode display component uses the STM display driver library, so I think it's less likely to be a software issue.
How is the power supply? If using USB, is it a good quality cable?
Anything else connected to the board?
Do you have another Disco' board to try?
btw. Your first post mentions STM32F449I, do you mean 469?

[achillis1]

Actually the longer delay does not fix the issue. The effect is so brief that seems that it isnt there!
yes the board is STM32F469I - disco
So if I have a routine that continuously updates the screen, then for example a dot in the leftmost side of the screen will be drawn all the way to the right, thus giving like a straight line. It is like the whole screen output continuously shifts.
I have used several USB cables, still the same.

Finally I have managed to load and program my board using the TouchGfx designer and the demo I used from their library works just fine!

[LeighM]

I can’t help much further, I don’t have v8 or a STM32F469I disco board, only other thoughts are:
• Does it work OK in Flowcode simulation?
• What does a simple Initialise and print Hello World do?
• Try Flowcode V11?
• Maybe Matrix have a STM32F469I discovery board to test?

[BenR]

I've had a dig and can't seem to put my hands on it.

Can you create a simple video showing the problem and that might help us to understand and identify where the problem lies.

Trying Flowcode v11 would also be useful as lots has changed since v8 and we likely wouldn't be able to roll out a fix for that.