it only works at all with 128k or 256k non-psram builds
you can hear the beep when you adjust the slider in control panel, but
there's other audio overlaid on it that is kind of a weird descending tone,
very regular in nature.
The sample rate is set to 20k not 22.255k because of my i2s dac not
liking random sample rates.
Instead of using the i2s dac on the fruit jam, this uses A0 (data),
A1 (lrck), A2 (bclk). It's not super convenient, and it's hard coded.
Some configurations that actually work at the time I committed this:
./fruitjam-build.sh -v # vga resolution, no psram, 128KiB
./fruitjam-build.sh -v -m448 # vga resolution, no psram, 448KiB
./fruitjam-build.sh -m4096 # 512x342 resolution, psram, 4096KiB
this is a _workaround_ for the fact that the mac framebuffer is inverted.
we'll probably ditch it again once we copy the (512x342) framebuffer
from PSRAM to SRAM....
Adds a new build option, -DVIDEO_PIN=<n>, which sets the base GPIO
of Video (followed by syncs).
The video pins (for PIO reasons) need to be contiguous, numbered upward
from the DATA pin. This has caught a couple of people out, so to make
it easier just define them this way. That then gives a single
configuration option, the first GPIO, setting it all up.
