BBS BUFFER A

BBS_BUFFER_A

BAMBU Filament Buffer alternative with super cheap component

Minimal, fast, and hardware‑focused firmware for the CH32V003.
This project currently ships a clean ADC → PWM control loop with button‑driven calibration stored in flash.

Built with GPT Codex 5.2.

Based on the original BBS Buffer A project: https://github.com/4061N/BBS-Buffer-A

Highlights

• 10‑bit ADC read on PA2, mapped to PWM duty.
• PWM output on PC4 (TIM1 CH4) by default.
• Short/long press calibration on PC1:
  • Short press → save min ADC
  • Long press → save max ADC
• Calibration stored in on‑chip flash (EEPROM‑style).
• UART debug prints on PD5 (115200 8N1).

Quick Start (PlatformIO)

From repo root:

pio run -e genericCH32V003A4M6
pio run -t upload -e genericCH32V003A4M6

Pin Map (current firmware)

• PA2: ADC input
• PC4: PWM output (TIM1 CH4)
• PC1: Button input (internal pull‑up, active‑low)
• PD5: UART TX (115200 8N1)
• PC2: WS2812 data (optional, not used by default)

Calibration Behavior

On button release:

• Press < BUTTON_LONG_MS → save min ADC
• Press ≥ BUTTON_LONG_MS → save max ADC

Saved values are written to the last flash page and loaded on boot.
If flash data is invalid, firmware falls back to defaults.

Key Config Macros (src/main.c)

• USE_CALC — enable/disable flash calibration
• UART_ENABLE — UART debug prints
• PWM_USE_PC4 — choose PWM pin (PC4 vs PA1)
• ADC_MIN_DEFAULT, ADC_MAX_DEFAULT — fallback range
• BUTTON_LONG_MS — long‑press threshold

Files of Interest

• src/main.c — main control loop
• src/calibration.c / include/calibration.h — flash storage helpers

Notes

Flash writes erase a full page. Avoid saving excessively in tight loops.

Recommended 3D Model

BBS Buffer A XMCU Series Buffer 3D model