TouchGFX: How to enable an external data reader?

[TMack.1]

I am implementing a low cost custom TouchGFX project using a stm342G071 and an ILI9488 based display. For the ILI9488 driver I need the touchGFX framebuffer in RGB888 format.

This works ok if I keep the image data in internal flash but I need to put this data in an external spi flash and cannot work out how to do this. All the tutorials I have found suggest that the external flash needs to be memory mapped but the G071 does not support this.

However TouchGFX has example projects for the G071 using the GFX01M2 display module which does use external, non memory mapped, SPI flash. Looking at the ioc configuration for that project I have found that it gives the option of a External Data Reader if the framebuffer is RBG565 but not for any other format.

Is there a way of using an external data reader with other formats, eg RGB888? Or is it really the case that low cost solutions are limited to just RGB565 frame buffers?

[N. SANTINI · Accepted solution]

Hi,

Indeed the first use case that has been foreseen regarding the DataReader feature is for entry-level MCUs and thus RGB565 format support.

RGB565 means smaller pixel information and thus lower memory transfers which make sense for entry-level MCUs such as the STMG071.

So for the time being this feature is limited to RGB565, without transparency, RGB888 support could come in the future depending on the demand.

Best regards,

Nicolas