Logic Technology: high quality graphics using only internal memory
Users expect smartphone look and feel, not acknowledging the constraints of limited resources on microcontroller setups. The user expectations require 16-bit color depth normally pushing one to use external SD-RAM for two framebuffers. This requirement for external memory increases the complexity and cost of the hardware development and production cost. We experience a hard push from high volume product manufactures towards saving of external RAM, accepting only a minor UI performance limitation.
Popular microcontrollers from ST targeting GUI applications contain enough internal memory to hold one framebuffer + TouchGFX stack + RTOS. TouchGFX Stack + RTOS requires around 30k to 50KB RAM. The architecture of the TouchGFX framework allows you to run on internal memory alone using only one framebuffer and still obtain a high frame rate even with full screen animations and smart effects.
When a device is only using one framebuffer, it is important that the graphics framework does not draw to the framebuffer at the same time as the TFT controller is outputting the pixels to the screen. Otherwise, the result will be a mix of the old and the new frame (image tearing). TouchGFX controls this with an incremental algorithm that updates the framebuffer simultaneously with the TFT controller outputting pixels, but always only updating the pixels that the TFT controller has already transferred. TouchGFX takes care of all this, allowing the application programmer to focus on realization of the design achieving smooth animations with up to 60 Hz framerate.
Many microcontrollers from ST, including the listed above, contains the Chrom ART Accelerator. This accelerator doubles the performance in many graphics primitives like image composition and text rendering. TouchGFX comes with full support of the Chrom-ART Accelerator. TouchGFX allows you to use the full potential of ST microcontroller based solution leveraging the combination of a single framebuffer in internal memory and the Chrom ART Accelerator.