CONTEXT.md

Session Context

What we did

1. Explored the CardShuffler project structure and architecture
2. Discussed TB6612FNG motor driver usage (PWM control on GPIO 2, 3)
3. Created wiring diagram: docs/wiring-diagram.txt
4. Committed the wiring diagram
5. Updated ST7735 pin names in wiring diagram to match display board labels (SCL, RES)
6. Added MOTOR_MAX_SPEED 65 in config.h to limit PWM for FA-130 motors
7. Applied max speed limit in motor_set_speed(), motor_ramp_to(), motor_ramp_both()
8. Added bootloader reboot on long press (reset_usb_boot)
9. Saved all component photos locally in docs/, updated README to use local paths
10. Added TB6612FNG, LX-LCBST, LiPo, FA-130 motor photos
11. Updated wiring diagram: TB6612FNG powered directly from LX-LCBST 5V
12. Fixed README: pin assignments (Encoder BTN=GP4, Extra=GP16, A=GP15, B=GP14)
13. Fixed README: renamed "Custom" strategy to "Random"
14. Added missing components to Hardware table (FA-130, LX-LCBST, Li-Po)

Pending changes

None — all changes committed and pushed.

Hardware

• RP2040-Zero — microcontroller
• ST7735 128x160 — SPI display (3V3, GPIO 5-10)
• KY-040 — rotary encoder (GPIO 4, 14, 15, internal pull-ups)
• TB6612FNG — motor driver (GPIO 2-3 PWM, VCC+VM from LX-LCBST 5V)
• 2x FA-130 — DC motors ∅20mm, 1.5–3V, PWM limited to 65% (~3.25V)
• LX-LCBST — boost converter 3.7V → 5V
• 1S Li-Po — 3.7V 500mAh+ battery

Photos in docs/

• card-shuffler.png — шафл-машинка
• st7735.png — дисплей
• rp2040-zero.jpg — микроконтроллер
• ky040.png — энкодер
• tb6612fng.jpg — драйвер моторов
• motor-fa130.jpg — мотор
• lx-lcbst.jpg — boost converter
• lipo.jpg — аккумулятор
• display-menu.gif — меню на дисплее

Project summary

Card Shuffler firmware for RP2040-Zero:

• 6 shuffle strategies: Quick, Riffle, Strip, Wash, Box, Random
• State machine: MENU → SHUFFLING → STOPPING
• PWM motor control (25kHz) with soft start/stop ramping

Build

make        # build
make flash  # build and flash