alternative to TICK_INTERVAL_MS constant in touchFGX

[AJT141]

Hello,

I'm wondering if there is a an alternative to TICK_INTERVAL_MS constant which is deprecated. It is said that handleTickEvent() function is called by the Application on the current screen with a frequency of Application::TICK_INTERVAL_MS.

For the moment I've changed the frequency at which handleTickEvent() is called with this code :

/**
     * Has to be called from within the LCD IRQ rutine when the Back Porch Exit is reached.
     *
     * Has to be called from within the LCD IRQ rutine when the Back Porch Exit is reached.
     */
    virtual void backPorchExited()
    {   
        static int cnt = 0;
        static int modulo = 2;
        if(cnt%modulo ==0)
        {
            swapFrameBuffers();
            tick();
        }
        cnt++;
    }

(Here i got the same LTDC frequency but the frequency display is divided by 2)

regards,

AJT

[Alexandre RENOUX]

Hello,

I'm not sure I get your point. Why do you want to change the frequency at which handleTickEvent() is called ?

handleTickEvent() is called every "display tick" which refers to every time a Tearing Effect event sent from the display is received by the MCU. Usually this period is around 16 ms.

/Alexandre

[AJT141]

Hello​

I​ just want to change the frequency of the display so instead decreasing frequency of the LTDC screen that leads to display glitches (like screen flickering), I change how many time we call handTIckEvent function.

And I don't want to change all screens handletickevent functions so is there a proper way to do that or did I do the right thing ?

Regards,

Ajt​

[Alexandre RENOUX · Accepted solution]

To do so, you have to modify the HAL_LTDC_LineEventCallback() function.

Basically you are preventing the TouchGFX framework to render a new frame every time the display has finished refreshing itself.

You do so by calling OSWrappers::signalVSync() only every x display refreshes.

Here is a sample code :

extern "C"
{
static volatile uint8_t renderNextFrameNb = 1;
 
    void HAL_LTDC_LineEventCallback(LTDC_HandleTypeDef* hltdc)
    {
        if (LTDC->LIPCR == lcd_int_active_line)
        {
            //entering active area
            HAL_LTDC_ProgramLineEvent(hltdc, lcd_int_porch_line);
 
             if(renderNextFrameNb%x == 0)
             {
                   HAL::getInstance()->vSync();
                   OSWrappers::signalVSync();
                   // Swap frame buffers immediately instead of waiting for the task to be scheduled in.
                   // Note: task will also swap when it wakes up, but that operation is guarded and will not have
                  // any effect if already swapped.
                  HAL::getInstance()->swapFrameBuffers();
                  GPIO::set(GPIO::VSYNC_FREQ);
             }
            
        }
        else
        {
            //exiting active area
            HAL_LTDC_ProgramLineEvent(hltdc, lcd_int_active_line);
             if(renderNextFrameNb%x == 0)
             {
                   GPIO::clear(GPIO::VSYNC_FREQ);
                   HAL::getInstance()->frontPorchEntered();
             }
             renderNextFrameNb++;
             if(renderNextFrameNb > x)
             {
                   renderNextFrameNb = 0;
             }
        }
    }
}

When your question is answered, please close this topic by choosing Select as Best.

/Alexandre

[AJT141]

Looks like it is working !

Thank you !