Posted on October 22, 2015 at 17:51
Hello,
I'm targeting the STM32F429IIT6.
I have a problem with the LTDC driver clock.
I'm trying to drive this 800x480
http://www.newhavendisplay.com/specs/NHD-7.0-800480EF-ATXL-CTP.pdf
at 30 fps.
In my system clock configuration, I have something like this :
PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_LTDC;
PeriphClkInitStruct.PLLSAI.PLLSAIN = 120;
PeriphClkInitStruct.PLLSAI.PLLSAIR = 4;
PeriphClkInitStruct.PLLSAIDivR = RCC_PLLSAIDIVR_4;
HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct);
HAL_SYSTICK_Config(HAL_RCC_GetHCLKFreq()/1000);
HAL_SYSTICK_CLKSourceConfig(SYSTICK_CLKSOURCE_HCLK);
With this I get a display with a visible scan line like shown
http://imgur.com/ZRgDCOG
(120/4/4 = 7.5 MHz for the pixel clock).
According to the datasheet, the maximum pixel clock supported is 50MHz (from which we are quite far).
As soon as I try to bring the pixel clock a little higher :
PeriphClkInitStruct.PLLSAI.PLLSAIR = 2;
PeriphClkInitStruct.PLLSAIDivR = RCC_PLLSAIDIVR_4;
or :
PeriphClkInitStruct.PLLSAI.PLLSAIR = 2;
PeriphClkInitStruct.PLLSAIDivR = RCC_PLLSAIDIVR_2;
I get
http://imgur.com/VzYVCDu
.
Am I doing something horribly wrong?
#stm32f429-ltdc-lcd-tft-clock
