GD3X is alive

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Last week I had just hand assembled the first prototype of GD3X. This week I'm delighted to report that it's running perfectly, and ready to go to manufacturing.

GD3X has:

• Bridgetek BT816 3rd generation Embedded Video Engine (EVE) running at 72 MHz
• 4.3" and 7" touchscreen with dimmable backlight
• Audio out through headphone jack
• microSD slot
• 8 Mbyte onboard QSPI flash

The onboard flash is a new feature. The BT816 has a 288 Mbit/s interface to flash, so it can load and draw graphics from it. Together with ASTC, this means that you can get an amazing amount of high-quality graphics.

ASTC is a lossy compression system for images, like JPEG. However unlike JPEG it's designed so that GPUs (like EVE) can access the image directly, without having to decompress it first. The 2nd generation EVE added hardware JPEG support, but you had to decompress the JPEG into graphics memory before you could draw it. With ASTC you just load the compressed data into graphics memory, and the hardware can use it as an image.


The 320x200 image here takes 192K if encoded as 24-bit RGB. As ASTC it takes only 10K. That's a huge compression ratio. Put another way, GD3 holds 5 images like this in RAM. GD3X can hold 100.

I'm driving it with a SPIDriver and some Python diagnostics.

The GD3X came to life immediately, and all the subsystems (video, backlight, touchscreen, audio, microSD, flash) worked perfectly first time. The BT816 is backwards-compatible with the FT812. There will be a minor tweak to gd2-lib to load configuration from flash, and of course some new APIs for the new features of BT815/816.

Apart from the external flash interface and ASTC, the BT815 improves on the 2nd generation FT810 with:

• internal clock frequency increase from 60 to 72 MHz for a peak fill rate of 1.1 Gpixels/s
• new commands for flash erase, write and read
• animation! Up to 32 concurrent animations on-screen, played back from flash
• better rotating bitmap support
• improved text support with new printf-style formatting options and multi-line text wrapping
• Unicode font support

gd2-asset is the open-source asset converter for Gameduino 2/3, and I will be working on the enhancements for GD3X in the weeks leading up to the launch.