Pico Computer 3 v0.4 (test)

Pico Computer 3 v0.4 (test)

A MicroPython (RP2350B) firmware for the Pico Computer 3 standalone board.

Install

Hold BOOTSEL while powering up, then copy firmware.uf2 to the RPI-RP2
drive that appears. The board reboots into MicroPython; the REPL banner reads
MicroPython v1.29.0-preview on PICO COMPUTER 3 v0.4 with RP2350B.

What's new since v0.3

Audio: tracker music, tones and a synthesiser

• MOD tracker playback — play("/sd/song.mod", loop=True) plays Amiga MOD
  music with the hxcmod engine (returns the song title). mod_sample(n) fires
  one of the module's instrument samples as a sound effect mixed over the
  running music — background music plus game SFX from a single file.
• tone(left, right, ms) — two independent sine-wave channels. Calling
  tone() again while one plays retunes it seamlessly (click-free), so
  melodies and arpeggios work.
• sound(voice, side, wave, freq, vol) — a 4-voice synthesiser with
  sine / square / triangle / sawtooth / periodic-noise / white-noise waveforms
  per voice and side; volume changes ramp to avoid clicks.
• pause() / resume() for the current playback.

Graphics: layers, off-screen buffers, a blitter and a sprite engine

• Overlay layer + off-screen framebuffer — hdmi.layer() adds a
  transparent overlay merged live over the display (RGB320); hdmi.create()
  adds an off-screen buffer in PSRAM. hdmi.write("N"/"L"/"F") chooses where
  all drawing goes (including the image loaders and console), and
  hdmi.copy(src, dst) block-copies whole buffers.
• hdmi.blit(x, y, w, h, x1, y1, src, dst, skip) — a rectangle blitter
  that copies within or between buffers (or to/from RAM (buffer, w, h)
  surfaces), with an optional skip colour for cut-out sprites; overlapping
  copies are safe in any direction.
• hdmi.vsync() — wait for vertical blanking for tear-free updates and
  frame pacing (input and audio keep running while it waits).
• pcsprite — a full sprite engine (import pcsprite): layers, AABB
  collisions (sprites, screen edges and static walls, edge-triggered), z-order
  and background scrolling — MMBasic sprite semantics on a dirty-rectangle /
  overlay-layer compositor. update() commits moves and returns collisions.

Input

• keydown(n) — read which keys are held right now (not just typed
  characters) — essential for games: count, per-key codes, modifier and lock
  bitmaps.
• keyboard.on_key(cb) — a callback on every keypress / auto-repeat.
• Num Lock now defaults on and, when off, the numeric keypad acts as the
  navigation cluster (arrows / Home / End / PgUp / PgDn / Ins / Del).

Console

• console("both" / "serial" / "screen") routes console output
  (MMBasic OPTION CONSOLE) — keep prints off the HDMI screen while testing
  graphics, or off the serial port; keyboard input always works. Power-up
  default is both.
• On-screen editor scrolling now works: the pcconsole terminal emulator
  gained a scroll region (DECSTBM) and reverse index, so the pye editor
  scrolls correctly on the HDMI screen (not just over serial).

Reliability

• DS3231 RTC survives a live CPU-clock change — the I2C bus is rebuilt when
  screen(mode, 315/378) changes the clock, so gettime/settime stay
  correct.
• On-device test suite — boards/PICO_COMPUTER_3/tests/ (copy to the SD
  card, run("test_all.py")): pixel-verified automatic tests for the blitter,
  buffers, sprites and images, plus interactive tests for the keyboard, audio
  and console routing.

See USER_MANUAL.md (in the board directory) for full documentation.