ST STM32L496 Series, Application Note, Page: 6 / 22

Chrom-ART Accelerator™ (DMA2D) application use case overview AN4943
6/22 DocID029937 Rev 2
2 Chrom-ART Accelerator™ (DMA2D) application use
case overview
A typical application displaying an image into an LCD-TFT display is divided in 2 steps.
•
Step1: creation of the frame buffer content
–
The frame buffer is built by composing graphical primitives like icons, pictures and
fonts
– This operation is done by the CPU running a graphical library software
– It can be accelerated by a dedicated hardware used with the CPU through the
graphical library (Chrom-ART Accelerator™ (DMA2D))
– The more often the frame buffer is updated, the more fluid are the animations
•
Step2: display of the frame buffer onto the LCD-TFT display
–
The frame buffer is transferred to the display through a dedicated hardware
interface
– The transfer can be done using the CPU, the system DMA or using the Chrom-
ART Accelerator™ (DMA2D)
In a typical display application example using the STM32L496xx/L4A6xx/L4Rxxx/L4Sxxx
microcontrollers, the Flexible Static Memory Controller (FSMC) is used as the hardware
interface to the LCD-TFT display, the graphical primitives like pictures, icons or fonts are
stored in the external Quad-SPI Flash memory and the frame buffer is stored in the internal
SRAM. The transfer of the frame buffer to the LCD-TFT display can also be managed by the
Chrom-ART Accelerator™ (DMA2D), hence not using the CPU or the DMA resources.
This is showed in Figure 1: Display application typical use case .
Figure 1. Display application typical use case
MSv44235V2
Frame buffer in
internal SRAM
STM32L496xx/L4A6xx/L4Rxxx/L4Sxxx
SRAM
DMA2D
FSMC
LCD-TFT
display
Quad-SPI
Flash
Quad-SPI
interface
Graphical primitives in external
Quad-SPI Flash memory
Step 1
Step 2