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]

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 !