The upgrade was pretty straightforward, because of the hardware abstraction layer in the code I practically only had to adapt the TFT drivers for the ILI9488 specifics. I use the ILI9488 in 4 wire SPI mode, this only allows for RGB666 i.e. 18bpp. That’s three bytes per pixel, so memory usage is up compared to the previously used RGB565 16bpp or two bytes per pixel. Since the GUI library uses double video buffering, the increased resolution and bpp requirements mean more memory is used. To mitigate this, I chose to use an ESP32 WROVER SoC that includes external RAM available.
In addition, I modified the RFM69 footprint, so that I can alternatively use
I managed to get the ILI9488 to work well clocked at 40MHz with DMA. It is reasonably fast, see it in action here:
Bigger is better they say. Or is it? This TFT costs twice the 2.4″ version, requires significantly more memory to run.
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