Serial uploader was crashing the Pico when launching games because
it accessed SD card (SPI) while Core 1 was refreshing display (also SPI).
Display and SD card share the same SPI bus and cannot be accessed
simultaneously.
Split game launch into prepare and execute phases:
- prepare: Re-scan games directory (safe, SD access done immediately)
- execute: Load Lua script from SD (deferred until display is idle)
Main loop now checks !is_refresh_in_progress() before completing
launch, preventing SPI conflicts.
Also updated SD card best practices skill to document SPI bus
contention as the #1 most critical issue to avoid.
Co-Authored-By: Claude <noreply@anthropic.com>
Implements a complete serial upload workflow that allows uploading and
immediately testing Lua games via USB serial connection.
New Components:
- SerialUploader: Receives files via serial, writes to SD card
- upload_game.py: Python tool for sending files from host computer
- Protocol: Text-based with base64 encoding for reliability
Key Features:
- Uploads file to /games folder on SD card
- Overwrites existing files (FA_CREATE_ALWAYS)
- Auto-launches uploaded game immediately
- Proper memory cleanup (prevents Lua state conflicts)
SD Card Fixes:
- Fixed SPI speed management (12.5MHz for SD, 32MHz for display)
- Fixed SD write protocol (poll for data response token)
- Added speed switching wrappers around all FatFS operations
- Cleaned up excessive debug output
Game Launcher Improvements:
- Added clear_games() to prevent duplicate registrations
- Added cleanup in select_game_by_name() to delete old instances
- Added exact match priority in game selection
- LuaGameLoader now has clear_factory_data() for memory cleanup
Integration:
- Added serial_uploader to CMakeLists.txt
- Integrated into main loop in basic1.cpp
- Re-scans games after upload to pick up new files
Documentation:
- UPLOAD_TOOL.md: Usage instructions
- sd_card_best_practices.md: Critical lessons learned
Known Issues:
- Game launch after upload occasionally causes freeze (needs investigation)
- Display may not refresh properly after upload
Usage:
python upload_game.py games/lua_examples/2048.lua /dev/tty.usbmodem101
Co-Authored-By: Claude <noreply@anthropic.com>
Add intelligent partial screen update system using bitwise XOR change detection
and 4-quadrant tracking (top-left, top-right, bottom-left, bottom-right). Each
changed pixel is routed to its quadrant, with sophisticated merge logic that
combines adjacent rectangles when beneficial (<40% overhead). This dramatically
reduces SPI bandwidth for UIs with scattered updates (e.g., corners, sidebars).
Key changes:
- 4-quadrant dirty rectangle tracking with automatic merging
- XOR-based change detection for fast byte-level comparison
- Expose st7796_set_window() for partial region updates
- 30 FPS frame rate limiter (33ms per frame) to prevent excessive refreshes
- Smart sleep timing when frame rate limit is active
Performance: Up to 99% reduction in SPI traffic for corner-based UIs
(e.g., 4 small regions vs full 480x320 screen updates).
Co-Authored-By: Claude <noreply@anthropic.com>
- Added PWM brightness control to ST7796 driver (0-100%)
- Implemented hardware sleep mode for ST7796 (saves ~150mA)
- Added sleep/wake functions preserving framebuffer and settings
- Implemented timer-based inactivity detection (checks every 10s)
- Auto-sleep after 5 minutes of no user input
- Touch controller remains active during TFT sleep for instant wake
- E-ink display also sleeps after timeout, requires re-init on wake
- Added hardware_pwm library dependency to CMakeLists.txt
- Brightness and sleep/wake methods exposed through display abstraction layer
- Added INPUT_FRAME_TICK event type to input_event.h
- Added wants_frame_updates() virtual method to Game base class
- Implemented frame tick logic in main loop (basic1.cpp and emulator/main.cpp)
- Added Lua bindings: game.set_frame_updates(bool) and INPUT.FRAME_TICK
- Updated LuaGame to support frame updates via registry flag
- Updated ball.lua to use continuous frame updates for smooth animation
- Both hardware and emulator now support continuous animation for physics/games
- Integrated Lua 5.4 engine (32-bit mode for embedded ARM)
- Created LuaGame wrapper class implementing Game interface
- Added C++ bindings exposing renderer, game state, and input to Lua
- Implemented SD card loader for automatic .lua game discovery
- Updated GameLauncher to support std::function for lambda captures
- Made Game class members public for Lua bindings access
- Added example Lua games: counter, snake, bouncing ball
- Included comprehensive API documentation
Games can now be written as .lua text files on SD card and loaded
without recompilation. Build size: 747KB UF2, Lua VM uses ~50-80KB RAM.
