GRG's Miscellany

My plan was always to do a SID-style synthesizer so I could make C64-style sounds on the picante. I've managed to make a thing! This is a software synth running on a RaspberryPi Pico attached to an Adafruit UDA1334 I2S module (recorded through the mic jack on my PC). Getting the UDA1334 working The official Adafruit guide was useful, but not perfect as it didn't cover the Pi Pico.  The micropython examples on how to play a tone and how to play a wav from an sd card were really  useful though. First, I got the play tone working, then I adapted the sd card (non-blocking) interrupt to play a continuous tone (which was just beautiful and didn't make my ears bleed at all). Starting on the Synth I then had to do a LOT of thinking about how I could make this synth fast enough and low-RAM enough for a Pi Pico.  After trying out a few combinations of parameters, I settled on a sampling rate of 16kHz and 16 bits per sample.  I wanted the synth to work on different wavef...

Picante: Basic Graphics Features Complete! The fundamental graphics feature set is there:  clearing the screen drawing 32x32 bitmaps with optional transparent colour index drawing coloured text from bitmap font All features are accessible via python script and clip against the screen edge. It's not yet built to be robust - I was having too much fun to bother writing exhaustive error checking. Whilst the basic design is meant to be fairly speedy without eating too much RAM, there's plenty more that can still be done to optimise it. Blitting: The tiles are processed from a single bitmap, but blitted individually (no fast tilemap feature yet).  It runs at about 15fps, all off a single core.    Text: The text is processed from a png into a 1bpp binary format for the picante engine to load.  This runs at about ~20fps. It's designed to be able to handle any font up to 8x16px, but I've only tested it with the 3x5 tom-thumb font so far.  The small screen really ne...