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3 years, 11 months ago.
How to use different Layers on Display of STM32F469?
I am using an STM32F469NI Discovery Board. I want to use the two layers for the display with the library LCD_DISCO_F469NI from mbed. The Display itself works as it should, but I can't select another display layer than the background layer. When I use the functions SelectLayer(1):
#include "mbed.h" /** * @brief Selects the LCD Layer. * @param LayerIndex: Layer foreground or background */ void SelectLayer(uint32_t LayerIndex);
and SetLayerVisible(1, ENABLE);
#include "mbed.h" /** * @brief Sets an LCD Layer visible * @param LayerIndex: Visible Layer * @param State: New state of the specified layer * This parameter can be one of the following values: * @arg ENABLE * @arg DISABLE */ void SetLayerVisible(uint32_t LayerIndex, FunctionalState State);
the display is not showing any difference and everything that is send to the display after SelectLayer is not shown. I know there are functions called LayerDefaultInit():
#include "mbed.h" /** * @brief Initializes the LCD layers. * @param LayerIndex: Layer foreground or background * @param FB_Address: Layer frame buffer * @retval None */ void LayerDefaultInit(uint16_t LayerIndex, uint32_t FB_Address);
#include "mbed.h" /** * @brief Sets an LCD layer frame buffer address. * @param LayerIndex: Layer foreground or background * @param Address: New LCD frame buffer value */ void SetLayerAddress(uint32_t LayerIndex, uint32_t Address);
but I don't know how to use them, the background layer is working without this functions, I have to set an FB_Address but I don't know which address I could use.
Sorry for my bad english, I hope that You understand what my problem is.
6 months, 3 weeks ago.
Let me answer with more background info. LTDC is using external RAM for both layer buffers (unless you are going monochrome or indexed, then you may think of putting one buffer inside MCU RAM, but it will be hard task anyway). On both STM32F469NI and STM769NI memory interface has too low bandwidth to refresh whole screen represented in two ARGB8888 layers without flickering. In case of two layers you must use 16- or 8-bit color representation (RGB565, ARGB1555, ARGB4444 or luminance based ones). BSP package provided by ST was written for ARGB8888 so you need to modify it to fit your needs.
3 years, 4 months ago.
I have similiar problem with STM32F469 Discovery. I use this sequence:
BSP_TS_Init(800, 480); BSP_QSPI_Init(); BSP_TS_ITConfig(); BSP_LCD_Init(); BSP_LCD_LayerDefaultInit(0, LCD_FB_START_ADDRESS); BSP_LCD_LayerDefaultInit(1, LCD_FB_START_ADDRESS+(BSP_LCD_GetXSize()*BSP_LCD_GetYSize()*4)); BSP_LCD_DisplayOn(); BSP_LCD_SelectLayer(0); BSP_LCD_Clear(LCD_COLOR_YELLOW); BSP_LCD_SelectLayer(1); BSP_LCD_Clear(LCD_COLOR_WHITE); BSP_LCD_SetTransparency(0, 0); BSP_LCD_SetTransparency(1, 255);
But without sucess. Only one LayerDefaultInit work OK 0 or 1 is same. But with two LayerDefaultInit together is problem. Display show only garbage.
I find many examples and code with this initialisation sequence for others Discovery kits. I am confused...
2 years, 4 months ago.
Hello! You have to hide the current layer too, and enable the other:
/* Initialize the LCD Layers */ BSP_LCD_LayerRgb565Init(1, LCD_FB_START_ADDRESS); BSP_LCD_LayerRgb565Init(0, LCD_FB_START_ADDRESS+(480*272*2)); Reserve memory art SRAM acc. resolution and color format
BSP_LCD_SelectLayer(0); BSP_LCD_SetLayerVisible(0, ENABLE); BSP_LCD_SetLayerVisible(1, DISABLE); Draw something on layer 0
At a given event change to layer 1: BSP_LCD_SelectLayer(1); BSP_LCD_SetLayerVisible(0, DISABLE); BSP_LCD_SetLayerVisible(1, ENABLE);