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M5Stack PaperS3 (4.7" ED047TC1)

The M5Stack PaperS3 is an ESP32-S3R8 board (16 MB flash / 8 MB octal PSRAM) — the S3 successor to the M5Paper v1.1, carrying the same ED047TC1 960×540 16-gray glass but with no IT8951 timing controller: the S3 clocks the panel directly over an 8-bit parallel bus, the same display class as the LilyGo T5 S3.

Pin map sources: M5GFX autodetect (board_M5PaperS3 in src/M5GFX.cpp), M5Unified (Power_Class, pin tables), the M5PaperS3-UserDemo HAL, and the official docs pinmap. Where the docs table disagrees (it labels GPIO45 "PWR" and omits GPIO16/GPIO46), M5GFX — the shipping vendor driver — is authoritative.

Display

LgfxEpdDriver (LovyanGFX Panel_EPD/Bus_EPD, bundled in m5stack/M5GFX) compiles under FREEINK_DRIVER_LGFX_EPD, derived from FREEINK_DEVICE_PAPERS3 just as it is from FREEINK_DEVICE_LILYGO. The parallel bus:

Signal GPIO Signal GPIO
D0 6 SPH (XSTL) 13
D1 14 CL (XCL) 16
D2 7 LE (XLE) 15
D3 12 SPV 17
D4 9 CKV 18
D5 11 OE 45
D6 8 PWR (EPD rail) 46
D7 10

Unlike the LilyGo (TPS65185 PMIC + PCA9535 expander), the PaperS3's EPD power is just the OE/PWR/SPV GPIOs, sequenced by Bus_EPD's stock powerControl (on: OE → PWR → SPV with settling delays; off in reverse). The board's LgfxEpdConfig (freeink::m5PaperS3LgfxConfig() in libs/hardware/BoardPaperS3) therefore carries real bus pins and null power hooks — LgfxEpdDriver's bus wrapper delegates to the base class when a hook is absent. Its prepare hook only parks the PWROFF pulse line (GPIO44) LOW.

Bus speed 16 MHz, line padding 8, rotation = 0 (the SDK's native-landscape convention, like the LilyGo; M5GFX ships the device portrait via offset_rotation=3). Pending hardware validation: if landscape "up" comes out inverted, set rotation 2 in the config.

M5GFX hard-requires OPI PSRAM on this board, so the env sets board_build.arduino.memory_type = qio_opi and -DBOARD_HAS_PSRAM.

Inputs — touch only

There are no firmware-readable buttons. The single side button feeds the PMS150G power-latch chip (press = on, 2 s hold = hard off, 6 s = reset) and never reaches an ESP32 GPIO. The profile's InputPins are all unassigned; paging and all navigation must come from the GT911 (tap zones / gestures / the firmware's touch paging). Firmware without touch page-turn support is unusable here.

  • GT911 touch — internal I²C bus SDA=GPIO41 / SCL=GPIO42 (shared with the RTC and IMU), INT=GPIO48, no reset wired (the controller self-loads its config, like M5Paper v1.1 → gt911CoordsAtByte0=true, pending validation), addresses 0x5D/0x14. Portrait digitizer (540×960) on the landscape panel → swapXY=true, rawMax in post-swap order (959×539); flipX=false, flipY=true mirror the LilyGo/M5Paper defaults pending a corner-tap test.
  • GPIO48 is not an RTC IO on the S3: touch cannot be a deep-sleep EXT wake source (M5Unified uses light-sleep GPIO wake instead).

Power

  • No power latch for firmware to hold — the PMS150G self-latches; the profile's PowerConfig is empty and holdPowerRails() is a no-op.
  • Software power-off = BoardPaperS3::powerOff(): a 5× 50 ms low/high pulse train on GPIO44 (a single edge does not release the latch — per M5Unified's power-off path). Idle level is LOW.
  • Wake-from-off via RTC: the BM8563's INT line feeds the PMS150G, not an ESP32 GPIO — set an RTC alarm before powering off.
  • USB detect — GPIO5, active-LOW: the pin is driven low while a cable is attached (measured on hardware: floating, pull-up and pull-down all read 0 with USB connected and the battery full). BoardProfile.usbDetectActiveHigh = false carries that, and BatteryMonitor::isExternalPowerPresent() answers from it — which also covers "cable in, battery full", where isCharging() is false.

Peripherals

  • Battery — ADC on GPIO3 (ADC1_CH2), 2:1 divider (pending validation); charge status GPIO4, LOW = charging (LGS4056H). No I²C fuel gauge.
  • RTC — BM8563 (PCF8563 register-compatible) at 0x51 on SDA41/SCL42, handled by the Rtc lib (RtcType::Pcf8563); CAP_RTC auto-on.
  • SD card — SPI/SdFat: SCLK=GPIO39, MISO=GPIO40, MOSI=GPIO38, CS=GPIO47. No power-enable gate. (Not SDMMC.)
  • Buzzer — LEDC tone on GPIO21 (Buzzer lib, CAP_BUZZER auto-on).
  • IMU — BMI270 at 0x68 on the internal bus. Not a supported ImuType yet, so it is omitted from the profile's sensors; adding it means a BMI270 backend in the Imu lib.
  • Status LED — a single PWM LED on GPIO0 (PAPERS3_LED). Not an addressable strip, so it is not in LedConfig — board-support/firmware drives it directly.
  • No frontlight, no microphone, no output codec.
  • Grove Port A — GPIO1 (SCL) / GPIO2 (SDA), external bus; not covered by the SDK.

Build

[env:papers3]  ; see platformio.sample.ini
board = esp32-s3-devkitc1-n16r8
board_build.arduino.memory_type = qio_opi
build_flags = -DBOARD_HAS_PSRAM -DFREEINK_DEVICE_PAPERS3=1
lib_deps =
  BoardPaperS3=symlink://freeink-sdk/libs/hardware/BoardPaperS3
  m5stack/M5GFX @ 0.2.33

No -DFREEINK_LGFX_EPD_CONFIG is needed: FREEINK_DEVICE_PAPERS3 selects m5PaperS3LgfxConfig() as the driver's config (an explicit -DFREEINK_LGFX_EPD_CONFIG=yourCfg still overrides it for custom boards).

Pending hardware validation

  • Panel rotation (0 vs 2) for the SDK's landscape convention.
  • Touch flipX/flipY (corner-tap test) and gt911CoordsAtByte0.
  • Battery divider ratio / ADC scaling.
  • SD SPI at the 40 MHz SdFat default (drop SdPins.spiHz to 20 MHz if mounts are flaky).