Add Waveshare ESP32-S3-Touch-AMOLED-1.8 (368×448) board support

Port the firmware to a second Waveshare AMOLED board variant alongside
the original 2.16" / 480×480. Selection is at build time via a board
macro; both envs continue to build and flash independently.

Hardware delta vs AMOLED-2.16:
  * Display: SH8601 QSPI (vs CO5300), 368×448 portrait (vs 480² square),
    SCLK on GPIO 11 (vs 38), RST routed through an XCA9554 I/O expander
    (vs direct GPIO).
  * Touch: FT3168 @ 0x38 (vs CST9220 @ 0x5A). Driven by a ~30-line
    inline FocalTech-protocol reader in main.cpp — Waveshare's
    Arduino_DriveBus library is GPLv3 and would force the project's
    license, which the README explicitly avoids.
  * I/O expander: new XCA9554/PCA9554 @ I2C 0x20 gates LCD_RST, TP_RST,
    audio amp enable, and the PWR button. Wrapped in io_expander.{h,cpp}.
    Must initialize BEFORE display/touch or both stay in reset.
  * PMU + IMU: same AXP2101 + QMI8658 as 2.16, so power.cpp/imu.cpp
    largely reuse. IMU is initialized for I2C bus health but rotation
    is fixed at 0° (the portrait panel doesn't benefit from auto-rotate
    and the strip-rotation CPU path is excluded entirely).
  * Buttons: only BOOT (GPIO 0) is a direct GPIO; PWR is read via
    XCA9554 EXIO4 polling. No third button — the AMOLED-2.16's
    Shift+Tab key (GPIO 18) is dropped for this board.
  * Flash: 16MB (vs 8MB), partition table set to default_16MB.csv.

Code structure:
  * display_cfg.h hosts a #ifdef BOARD_AMOLED_18 / #else / #endif split
    with a PlatformDisplay typedef so call sites elsewhere stay clean.
  * main.cpp, power.cpp, ui.cpp, splash.cpp gate board-specific bits on
    the same macro. Layout constants (panel heights, content Y, font
    choices on the Bluetooth screen) compress for the 368×448 portrait
    footprint so two usage panels + bottom animation label fit without
    horizontal overflow.
  * Splash scales the 20×20 pixel-art grid to 360×360 (CELL=18 vs 24)
    and centers in the portrait canvas.
  * Old AMOLED-2.16 env is unchanged at the source level (gated under
    #ifndef BOARD_AMOLED_18) and continues to compile + flash on the
    original hardware.

CLAUDE.md updated with the two-board pin maps, build/flash commands
for both envs (macOS + Linux device paths), and the per-board gotchas.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

firmware/src/display_cfg.h

@@ -1,11 +1,63 @@
 #pragma once
 
 #include <Arduino_GFX_Library.h>
-#include <TouchDrvCSTXXX.hpp>
 #include <XPowersLib.h>
 #include <SensorQMI8658.hpp>
 #include <Wire.h>
 
+// ============================================================================
+// Board variant selection — driven by build flag in platformio.ini
+//   -DBOARD_AMOLED_216  → original Waveshare ESP32-S3-Touch-AMOLED-2.16 (CO5300, CST9220, 480x480)
+//   -DBOARD_AMOLED_18   → newer Waveshare ESP32-S3-Touch-AMOLED-1.8     (SH8601, FT3168,  368x448)
+// ============================================================================
+
+#if defined(BOARD_AMOLED_18)
+
+// ---- Display resolution (portrait) ----
+#define LCD_WIDTH   368
+#define LCD_HEIGHT  448
+
+// ---- QSPI display pins (SH8601) ----
+#define LCD_CS      12
+#define LCD_SCLK    11        // NOTE: different from AMOLED-2.16 (was GPIO 38)
+#define LCD_SDIO0   4
+#define LCD_SDIO1   5
+#define LCD_SDIO2   6
+#define LCD_SDIO3   7
+#define LCD_RESET   GFX_NOT_DEFINED   // routed via XCA9554 EXIO1
+
+// ---- I2C bus (touch + PMU + IMU + IO expander all share one bus) ----
+#define IIC_SDA     15
+#define IIC_SCL     14
+
+// ---- Touch (FT3168 via I2C) ----
+#define TP_INT      21
+#define FT3168_ADDR 0x38
+
+// ---- PMU (AXP2101 via I2C) ----
+#define AXP2101_ADDR 0x34
+
+// ---- IO expander (XCA9554/PCA9554-compatible via I2C) ----
+// Gates LCD_RST, TP_RST, audio amp reset, and PWR button readback.
+#define XCA9554_ADDR 0x20
+#define IOX_PIN_TP_RST  0   // EXIO0 → touch reset (active LOW)
+#define IOX_PIN_LCD_RST 1   // EXIO1 → display reset (active LOW)
+#define IOX_PIN_PA_EN   2   // EXIO2 → audio amp enable (we keep HIGH to release)
+#define IOX_PIN_PWR_BTN 4   // EXIO4 → PWR button input, active HIGH
+
+// ---- Display class typedef ----
+typedef Arduino_SH8601 PlatformDisplay;
+
+// ---- Global hardware objects (defined in main.cpp) ----
+extern Arduino_DataBus *bus;
+extern PlatformDisplay *gfx;
+extern XPowersPMU pmu;
+extern SensorQMI8658 imu;
+
+#else  // BOARD_AMOLED_216 (default / original board)
+
+#include <TouchDrvCSTXXX.hpp>
+
 // ---- Display resolution ----
 #define LCD_WIDTH   480
 #define LCD_HEIGHT  480
@@ -29,9 +81,14 @@
 // ---- PMU (AXP2101 via same I2C) ----
 #define AXP2101_ADDR 0x34
 
+// ---- Display class typedef ----
+typedef Arduino_CO5300 PlatformDisplay;
+
 // ---- Global hardware objects (defined in main.cpp) ----
 extern Arduino_DataBus *bus;
-extern Arduino_CO5300 *gfx;
+extern PlatformDisplay *gfx;
 extern TouchDrvCST92xx touch;
 extern XPowersPMU pmu;
 extern SensorQMI8658 imu;
+
+#endif  // BOARD_AMOLED_*

firmware/src/io_expander.cpp

@@ -0,0 +1,72 @@
+#include "io_expander.h"
+
+#ifdef BOARD_AMOLED_18
+
+#include "display_cfg.h"
+#include <Arduino.h>
+#include <Wire.h>
+
+// XCA9554/PCA9554 register map
+#define IOX_REG_INPUT   0x00
+#define IOX_REG_OUTPUT  0x01
+#define IOX_REG_POLARITY 0x02
+#define IOX_REG_CONFIG  0x03   // 1 = input, 0 = output
+
+// EXIO0..2 are outputs (reset lines + audio amp). Everything else is input.
+// Bit layout: 0bIIIIIOOO = 0xF8
+#define IOX_CONFIG_MASK 0xF8
+
+// All three outputs HIGH = resets released, amp enabled.
+#define IOX_OUTPUT_DEFAULT 0x07
+
+static uint8_t output_state = 0x00;
+
+static bool write_reg(uint8_t reg, uint8_t val) {
+    Wire.beginTransmission(XCA9554_ADDR);
+    Wire.write(reg);
+    Wire.write(val);
+    return Wire.endTransmission() == 0;
+}
+
+static bool read_reg(uint8_t reg, uint8_t &val) {
+    Wire.beginTransmission(XCA9554_ADDR);
+    Wire.write(reg);
+    if (Wire.endTransmission(false) != 0) return false;
+    if (Wire.requestFrom(XCA9554_ADDR, (uint8_t)1) != 1) return false;
+    val = Wire.read();
+    return true;
+}
+
+bool io_expander_init(void) {
+    // 1. Configure direction: EXIO0..2 outputs, rest inputs.
+    if (!write_reg(IOX_REG_CONFIG, IOX_CONFIG_MASK)) {
+        Serial.println("XCA9554 init failed (config)");
+        return false;
+    }
+    // 2. Drive all outputs LOW → hold display + touch in reset.
+    output_state = 0x00;
+    write_reg(IOX_REG_OUTPUT, output_state);
+    delay(20);
+    // 3. Release resets and enable audio amp output line.
+    output_state = IOX_OUTPUT_DEFAULT;
+    write_reg(IOX_REG_OUTPUT, output_state);
+    delay(20);   // give SH8601 / FT3168 time to come out of reset
+    Serial.println("XCA9554 init OK");
+    return true;
+}
+
+void io_expander_set(uint8_t pin, bool high) {
+    if (pin > 7) return;
+    if (high) output_state |= (1u << pin);
+    else      output_state &= ~(1u << pin);
+    write_reg(IOX_REG_OUTPUT, output_state);
+}
+
+bool io_expander_get(uint8_t pin) {
+    if (pin > 7) return false;
+    uint8_t v = 0;
+    if (!read_reg(IOX_REG_INPUT, v)) return false;
+    return (v & (1u << pin)) != 0;
+}
+
+#endif  // BOARD_AMOLED_18

firmware/src/io_expander.h

@@ -0,0 +1,19 @@
+#pragma once
+
+#include <stdint.h>
+
+// XCA9554 / PCA9554-compatible 8-bit I2C IO expander @ 0x20.
+// Only compiled for BOARD_AMOLED_18 (the AMOLED-1.8 board routes LCD_RST,
+// TP_RST, audio amp enable, and the PWR button through this expander).
+//
+// Must be initialized BEFORE the display or touch — skipping the reset
+// release leaves the SH8601 and FT3168 in reset and they will fail to probe.
+
+bool io_expander_init(void);
+
+// Drive an EXIO pin (one of IOX_PIN_* in display_cfg.h that is configured
+// as output). Updates the cached output register.
+void io_expander_set(uint8_t pin, bool high);
+
+// Read an EXIO pin configured as input (e.g. PWR button on EXIO4).
+bool io_expander_get(uint8_t pin);

firmware/src/main.cpp

@@ -1,4 +1,5 @@
 #include <Arduino.h>
+#include <Wire.h>
 #include <lvgl.h>
 #include <ArduinoJson.h>
 #include "display_cfg.h"
@@ -12,26 +13,44 @@
 #include "idle.h"
 #include "idle_cfg.h"
 
+#ifdef BOARD_AMOLED_18
+#include "io_expander.h"
+#endif
+
 // Physical buttons (global, screen-independent):
-//   BTN_BACK   (GPIO 0)  — left,  send Space (Claude Code voice mode push-to-talk)
-//   BTN_FWD    (GPIO 18) — right, send Shift+Tab (Claude Code mode toggle)
-//   AXP PWR    (PMU)     — middle, cycle screens; on splash, cycle animations
+//   BTN_BACK (GPIO 0, BOOT)  — left, send Space (Claude Code voice-mode PTT)
+//   BTN_FWD  (GPIO 18)       — AMOLED-2.16 only: Shift+Tab (mode toggle)
+//   PWR                       — middle, cycle screens; on splash, cycle animations
+//                                AMOLED-2.16: AXP2101 PKEY IRQ
+//                                AMOLED-1.8 : XCA9554 EXIO4 (polled over I2C)
 #define BTN_BACK 0
+#ifndef BOARD_AMOLED_18
 #define BTN_FWD  18
+#endif
 
 // ---- Hardware objects ----
 Arduino_DataBus *bus = new Arduino_ESP32QSPI(
     LCD_CS, LCD_SCLK, LCD_SDIO0, LCD_SDIO1, LCD_SDIO2, LCD_SDIO3);
-Arduino_CO5300 *gfx = new Arduino_CO5300(
+#ifdef BOARD_AMOLED_18
+// SH8601 constructor: (bus, rst, rotation, w, h)
+PlatformDisplay *gfx = new PlatformDisplay(
+    bus, LCD_RESET /* GFX_NOT_DEFINED — reset via XCA9554 */, 0,
+    LCD_WIDTH, LCD_HEIGHT);
+#else
+// CO5300 constructor: (bus, rst, rotation, w, h, col_offset1..2, row_offset1..2)
+PlatformDisplay *gfx = new PlatformDisplay(
     bus, LCD_RESET, 0 /* rotation */,
     LCD_WIDTH, LCD_HEIGHT, 0, 0, 0, 0);
 TouchDrvCST92xx touch;
+#endif
 XPowersPMU pmu;
 SensorQMI8658 imu;
 
 static UsageData usage = {};
 
 // ---- Touch interrupt + shared state ----
+// Centralized once-per-loop read (CLAUDE.md gotcha #5): calling getPoint() /
+// reading FT3168 from multiple sites consumes each other's data.
 static volatile bool     touch_pressed = false;
 static volatile uint16_t touch_x = 0;
 static volatile uint16_t touch_y = 0;
@@ -41,10 +60,56 @@ static void IRAM_ATTR touch_isr(void) {
     touch_data_ready = true;
 }
 
+#ifdef BOARD_AMOLED_18
+// Minimal FT3168 reader (FocalTech standard register layout).
+// Avoids vendoring Waveshare's GPLv3 Arduino_DriveBus library.
+//   reg 0x02: low nibble = active finger count
+//   reg 0x03/0x04: X1 high (low nibble), X1 low
+//   reg 0x05/0x06: Y1 high (low nibble), Y1 low
+static void ft3168_init(void) {
+    // Power-mode register 0xA5 = 0x00: active scanning.
+    Wire.beginTransmission(FT3168_ADDR);
+    Wire.write(0xA5);
+    Wire.write(0x00);
+    Wire.endTransmission();
+    // Verify device ID register 0xA0 (FT3168 reports 0x03 but Waveshare's
+    // panel sometimes returns 0x86 — log but don't fail).
+    Wire.beginTransmission(FT3168_ADDR);
+    Wire.write(0xA0);
+    if (Wire.endTransmission(false) == 0 && Wire.requestFrom(FT3168_ADDR, (uint8_t)1) == 1) {
+        Serial.printf("FT3168 ID=0x%02X\n", Wire.read());
+    } else {
+        Serial.println("FT3168 ID read failed");
+    }
+}
+
+static void ft3168_read_into_shared_state(void) {
+    Wire.beginTransmission(FT3168_ADDR);
+    Wire.write(0x02);
+    if (Wire.endTransmission(false) != 0) { touch_pressed = false; return; }
+    if (Wire.requestFrom(FT3168_ADDR, (uint8_t)5) != 5) { touch_pressed = false; return; }
+    uint8_t fingers = Wire.read() & 0x0F;
+    uint8_t xH = Wire.read();
+    uint8_t xL = Wire.read();
+    uint8_t yH = Wire.read();
+    uint8_t yL = Wire.read();
+    if (fingers == 0 || fingers > 5) {
+        touch_pressed = false;
+        return;
+    }
+    touch_x = ((uint16_t)(xH & 0x0F) << 8) | xL;
+    touch_y = ((uint16_t)(yH & 0x0F) << 8) | yL;
+    touch_pressed = true;
+}
+#endif
+
 static void touch_read() {
     if (!touch_data_ready) return;
     touch_data_ready = false;
 
+#ifdef BOARD_AMOLED_18
+    ft3168_read_into_shared_state();
+#else
     int16_t tx[5], ty[5];
     uint8_t n = touch.getPoint(tx, ty, touch.getSupportTouchPoint());
     if (n > 0) {
@@ -54,6 +119,7 @@ static void touch_read() {
     } else {
         touch_pressed = false;
     }
+#endif
 
     // Touch policy is driven by IDLE_WAKE_ON_TOUCH:
     //   true  → a press edge while asleep wakes the device and the first
@@ -99,9 +165,11 @@ static uint32_t my_tick(void) {
     return millis();
 }
 
+#ifndef BOARD_AMOLED_18
 // Rotate a w×h strip and compute destination coordinates on the 480×480 display.
 // src pixels are in row-major order for the rectangle (sx, sy, w, h).
 // Output goes to rot_buf in row-major order for the destination rectangle.
+// AMOLED-1.8 port is fixed at 0° so this code is excluded.
 static void rotate_strip(const uint16_t *src, int32_t w, int32_t h,
                          int32_t sx, int32_t sy, uint8_t r,
                          int32_t *dx, int32_t *dy, int32_t *dw, int32_t *dh) {
@@ -148,14 +216,20 @@ static void rotate_strip(const uint16_t *src, int32_t w, int32_t h,
         break;
     }
 }
+#endif  // !BOARD_AMOLED_18
 
-// LVGL flush callback — rotates partial strips and writes to display
+// LVGL flush callback — writes pixels to display.
+// AMOLED-2.16: applies CPU strip rotation based on IMU.
+// AMOLED-1.8 : fixed orientation, direct pass-through.
 static void my_flush_cb(lv_display_t* disp, const lv_area_t* area, uint8_t* px_map) {
     int32_t w = area->x2 - area->x1 + 1;
     int32_t h = area->y2 - area->y1 + 1;
     uint16_t *src = (uint16_t*)px_map;
-    uint8_t r = imu_get_rotation();
 
+#ifdef BOARD_AMOLED_18
+    gfx->draw16bitRGBBitmap(area->x1, area->y1, src, w, h);
+#else
+    uint8_t r = imu_get_rotation();
     if (r == 0) {
         gfx->draw16bitRGBBitmap(area->x1, area->y1, src, w, h);
     } else {
@@ -163,10 +237,12 @@ static void my_flush_cb(lv_display_t* disp, const lv_area_t* area, uint8_t* px_m
         rotate_strip(src, w, h, area->x1, area->y1, r, &dx, &dy, &dw, &dh);
         gfx->draw16bitRGBBitmap(dx, dy, rot_buf, dw, dh);
     }
+#endif
     lv_display_flush_ready(disp);
 }
 
-// CO5300 requires even-aligned flush regions
+// CO5300 requires even-aligned flush regions. SH8601's driver doesn't
+// enforce this in source, but keeping the rounder is harmless.
 static void rounder_cb(lv_event_t* e) {
     lv_area_t *area = (lv_area_t*)lv_event_get_param(e);
     area->x1 = area->x1 & ~1;
@@ -260,9 +336,15 @@ void setup() {
     delay(300);
     Serial.println("{\"ready\":true}");
 
-    // Init I2C (shared by touch + PMU)
+    // Init I2C (shared by touch + PMU + IMU + IO expander)
     Wire.begin(IIC_SDA, IIC_SCL);
 
+#ifdef BOARD_AMOLED_18
+    // XCA9554 must come up FIRST — display + touch are held in reset until
+    // EXIO0..2 go HIGH (see io_expander_init()).
+    io_expander_init();
+#endif
+
     // Init display
     gfx->begin();
     gfx->fillScreen(0x0000);
@@ -271,10 +353,17 @@ void setup() {
     // Init PMU
     power_init();
 
-    // Init IMU (accelerometer for auto-rotation)
+    // Init IMU (accelerometer for auto-rotation; on AMOLED-1.8 we keep init
+    // for I2C bus health but ignore rotation — see imu.cpp).
     imu_init();
 
     // Init touch
+#ifdef BOARD_AMOLED_18
+    ft3168_init();
+    pinMode(TP_INT, INPUT_PULLUP);
+    attachInterrupt(TP_INT, touch_isr, FALLING);
+    Serial.println("FT3168 attached on INT pin");
+#else
     touch.setPins(TP_RST, TP_INT);
     if (!touch.begin(Wire, CST9220_ADDR, IIC_SDA, IIC_SCL)) {
         Serial.println("Touch init failed");
@@ -285,6 +374,7 @@ void setup() {
         attachInterrupt(TP_INT, touch_isr, FALLING);
         Serial.println("Touch init OK");
     }
+#endif
 
     // Init LVGL
     lv_init();
@@ -293,9 +383,11 @@ void setup() {
     // Allocate PSRAM-backed partial render buffers
     buf1 = (uint16_t*)heap_caps_malloc(LCD_WIDTH * BUF_LINES * 2, MALLOC_CAP_SPIRAM);
     buf2 = (uint16_t*)heap_caps_malloc(LCD_WIDTH * BUF_LINES * 2, MALLOC_CAP_SPIRAM);
-    // rot_buf needs to hold the largest possible strip after rotation
-    // A 480×40 strip rotated 90° becomes 40×480, same pixel count
+#ifndef BOARD_AMOLED_18
+    // rot_buf only needed for AMOLED-2.16 (CPU strip rotation).
+    // Holds the largest possible strip after rotation (same pixel count as src).
     rot_buf = (uint16_t*)heap_caps_malloc(LCD_WIDTH * BUF_LINES * 2, MALLOC_CAP_SPIRAM);
+#endif
 
     lv_display_t* disp = lv_display_create(LCD_WIDTH, LCD_HEIGHT);
     lv_display_set_color_format(disp, LV_COLOR_FORMAT_RGB565);
@@ -313,9 +405,11 @@ void setup() {
     // Init BLE data channel
     ble_init();
 
-    // Physical buttons: back (GPIO 0) and forward (GPIO 18)
+    // Physical buttons
     pinMode(BTN_BACK, INPUT_PULLUP);
+#ifndef BOARD_AMOLED_18
     pinMode(BTN_FWD,  INPUT_PULLUP);
+#endif
 
     // Build dashboard
     ui_init();
@@ -333,7 +427,9 @@ void setup() {
 
 static ble_state_t last_ble_state = BLE_STATE_INIT;
 
-// Brightness ramp state for rotation transition
+#ifndef BOARD_AMOLED_18
+// Brightness ramp state for rotation transition.
+// AMOLED-2.16 only — the 1.8" port is fixed at 0° (no IMU rotation).
 // On rotation change we blank the panel, force a full LVGL redraw at the
 // new orientation, then ramp brightness back up over ~125ms so the
 // transition reads as deliberate instead of as a glitch.
@@ -366,6 +462,7 @@ static void handle_rotation_change(void) {
     if (ramp_step >= 4) ramp_step = 0;
     else                ramp_step++;
 }
+#endif  // !BOARD_AMOLED_18
 
 void loop() {
     touch_read();
@@ -377,20 +474,23 @@ void loop() {
     imu_tick();
     splash_tick();
 
-    // Three-button input (global, screen-independent):
-    //   LEFT  (GPIO 0)  → Space (voice-mode push-to-talk; press & release tracked)
-    //   RIGHT (GPIO 18) → Shift+Tab (Claude Code mode toggle)
-    //   PWR   (AXP)     → cycle screens; on splash, cycle animations
+    // Physical button input (global, screen-independent):
+    //   LEFT (GPIO 0 / BOOT)  → Space (voice-mode push-to-talk)
+    //   RIGHT (GPIO 18)       → Shift+Tab (Claude Code mode toggle). AMOLED-2.16 only.
+    //   PWR                   → cycle screens; on splash, cycle animations.
+    //                           AMOLED-2.16: AXP2101 PKEY IRQ; AMOLED-1.8: XCA9554 EXIO4.
     // First press from sleep is consumed for wake only (idle_consume_wake_press
     // returns true) — the normal action only fires from the second press.
     // Activity bookkeeping happens inside idle_consume_wake_press, so no
     // separate idle_note_activity() call is needed here.
     {
-        static bool back_was = false, fwd_was = false;
-        static bool back_wake_swallowed = false, fwd_wake_swallowed = false;
+        static bool back_was = false;
+        static bool back_wake_swallowed = false;
+#ifndef BOARD_AMOLED_18
+        static bool fwd_was = false;
+        static bool fwd_wake_swallowed = false;
+#endif
         bool back_now = (digitalRead(BTN_BACK) == LOW);
-        bool fwd_now  = (digitalRead(BTN_FWD)  == LOW);
-
         if (back_now != back_was) {
             if (back_now) {
                 if (idle_consume_wake_press()) {
@@ -404,6 +504,9 @@ void loop() {
             }
             back_was = back_now;
         }
+
+#ifndef BOARD_AMOLED_18
+        bool fwd_now = (digitalRead(BTN_FWD) == LOW);
         if (fwd_now != fwd_was) {
             if (fwd_now) {
                 if (idle_consume_wake_press()) {
@@ -417,6 +520,7 @@ void loop() {
             }
             fwd_was = fwd_now;
         }
+#endif
 
         if (power_pwr_pressed()) {
             if (!idle_consume_wake_press()) {
@@ -426,7 +530,9 @@ void loop() {
         }
     }
 
+#ifndef BOARD_AMOLED_18
     handle_rotation_change();
+#endif
 
     // Update BLE status on screen when state changes
     ble_state_t bs = ble_get_state();

firmware/src/power.cpp

@@ -2,6 +2,10 @@
 #include "display_cfg.h"
 #include <Arduino.h>
 
+#ifdef BOARD_AMOLED_18
+#include "io_expander.h"
+#endif
+
 // Poll intervals
 #define BATTERY_POLL_MS   2000
 #define CHARGING_POLL_MS  500
@@ -15,6 +19,10 @@ static uint32_t last_charging_ms = 0;
 static uint32_t last_pwr_ms      = 0;
 #define PWR_POLL_MS 50
 
+#ifdef BOARD_AMOLED_18
+static bool last_pwr_state = false;   // edge detection for XCA9554 EXIO4
+#endif
+
 void power_init(void) {
     if (!pmu.begin(Wire, AXP2101_ADDR, IIC_SDA, IIC_SCL)) {
         Serial.println("AXP2101 init failed");
@@ -25,10 +33,14 @@ void power_init(void) {
     pmu.enableBattDetection();
     pmu.enableBattVoltageMeasure();
 
-    // Enable PWR button short-press IRQ (mid button for cycling screens)
+#ifndef BOARD_AMOLED_18
+    // AMOLED-2.16: PWR button events come from AXP2101 PKEY short-press IRQ.
+    // AMOLED-1.8 routes the PWR button through XCA9554 EXIO4 instead — we
+    // poll it in power_tick() rather than subscribing to the PMU IRQ.
     pmu.disableIRQ(XPOWERS_AXP2101_ALL_IRQ);
     pmu.clearIrqStatus();
     pmu.enableIRQ(XPOWERS_AXP2101_PKEY_SHORT_IRQ);
+#endif
 
     cached_charging = pmu.isCharging();
     cached_vbus     = pmu.isVbusIn();
@@ -49,14 +61,23 @@ void power_tick(void) {
         cached_pct = pmu.getBatteryPercent();
     }
 
-    // Poll PWR button (AXP2101 short-press IRQ)
+    // Poll PWR button
     if (now - last_pwr_ms >= PWR_POLL_MS) {
         last_pwr_ms = now;
+#ifdef BOARD_AMOLED_18
+        // XCA9554 EXIO4 — active HIGH, edge-trigger on press
+        bool pwr_now = io_expander_get(IOX_PIN_PWR_BTN);
+        if (pwr_now && !last_pwr_state) {
+            pwr_pressed_flag = true;
+        }
+        last_pwr_state = pwr_now;
+#else
         pmu.getIrqStatus();
         if (pmu.isPekeyShortPressIrq()) {
             pwr_pressed_flag = true;
         }
         pmu.clearIrqStatus();
+#endif
     }
 }
 

firmware/src/splash.cpp

@@ -2,13 +2,21 @@
 #include "splash_animations.h"
 #include "theme.h"
 #include "usage_rate.h"
+#include "display_cfg.h"
 #include <Arduino.h>
 #include <string.h>
 #include <esp_heap_caps.h>
 
-// 20x20 grid scaled 24x to fill 480x480
+// 20x20 grid. CELL chosen per board so the canvas fits the screen
+// (must satisfy GRID*CELL <= min(LCD_WIDTH, LCD_HEIGHT)).
+//   AMOLED-2.16 (480x480 square): CELL=24 → 480x480 fills screen
+//   AMOLED-1.8  (368x448 portrait): CELL=18 → 360x360 centered, vertical margin
 #define GRID         20
+#ifdef BOARD_AMOLED_18
+#define CELL         18
+#else
 #define CELL         24
+#endif
 #define CANVAS_W     (GRID * CELL)
 #define CANVAS_H     (GRID * CELL)
 
@@ -99,7 +107,7 @@ void splash_init(lv_obj_t *parent) {
     }
 
     splash_container = lv_obj_create(parent);
-    lv_obj_set_size(splash_container, 480, 480);
+    lv_obj_set_size(splash_container, LCD_WIDTH, LCD_HEIGHT);
     lv_obj_set_pos(splash_container, 0, 0);
     lv_obj_set_style_bg_color(splash_container, THEME_BG, 0);
     lv_obj_set_style_bg_opa(splash_container, LV_OPA_COVER, 0);

firmware/src/ui.cpp

@@ -7,12 +7,31 @@
 
 // Custom fonts (scaled for 314 PPI, ~1.9x from original 165 PPI)
 LV_FONT_DECLARE(font_tiempos_56);
+LV_FONT_DECLARE(font_tiempos_34);
 LV_FONT_DECLARE(font_styrene_48);
 LV_FONT_DECLARE(font_styrene_28);
 LV_FONT_DECLARE(font_styrene_24);
 LV_FONT_DECLARE(font_styrene_20);
+LV_FONT_DECLARE(font_styrene_16);
+LV_FONT_DECLARE(font_styrene_14);
 LV_FONT_DECLARE(font_mono_32);
 
+// AMOLED-1.8 (368 wide) needs smaller fonts on the Bluetooth screen so the
+// MAC address and credit lines don't overflow horizontally.
+#ifdef BOARD_AMOLED_18
+#define BT_TITLE_FONT     font_tiempos_34
+#define BT_STATUS_FONT    font_styrene_28
+#define BT_DEVICE_FONT    font_styrene_20
+#define BT_CREDIT_1_FONT  font_styrene_16
+#define BT_CREDIT_2_FONT  font_styrene_14
+#else
+#define BT_TITLE_FONT     font_tiempos_56
+#define BT_STATUS_FONT    font_styrene_48
+#define BT_DEVICE_FONT    font_styrene_28
+#define BT_CREDIT_1_FONT  font_styrene_24
+#define BT_CREDIT_2_FONT  font_styrene_20
+#endif
+
 // Anthropic brand palette — design tokens live in theme.h
 #include "theme.h"
 #define COL_BG        THEME_BG
@@ -25,13 +44,19 @@ LV_FONT_DECLARE(font_mono_32);
 #define COL_RED       THEME_RED
 #define COL_BAR_BG    THEME_BAR_BG
 
-// ---- Layout constants for 480x480 (scaled for 2.16" high-DPI + rounded corners) ----
-#define SCR_W         480
-#define SCR_H         480
-#define MARGIN        20    // wider margin for rounded display corners
+// ---- Layout constants ----
+// Width/height track the active display (480x480 for AMOLED-2.16, 368x448 for AMOLED-1.8).
+// MARGIN clears rounded display corners on both panels.
+#define SCR_W         LCD_WIDTH
+#define SCR_H         LCD_HEIGHT
+#define MARGIN        20
 #define TITLE_Y       30
+#ifdef BOARD_AMOLED_18
+#define CONTENT_Y     85    // tighter vertical packing for 448-tall portrait
+#else
 #define CONTENT_Y     100
-#define CONTENT_W     (SCR_W - 2 * MARGIN)   // 440
+#endif
+#define CONTENT_W     (SCR_W - 2 * MARGIN)
 
 // ---- Usage screen widgets ----
 static lv_obj_t* usage_container;
@@ -218,14 +243,26 @@ static void init_battery_icons(void) {
     init_icon_dsc_rgb565a8(&battery_dscs[4], ICON_BATTERY_CHARGING_W, ICON_BATTERY_CHARGING_H, icon_battery_charging_data);
 }
 
-// ======== Usage Screen (480x480) ========
+// ======== Usage Screen ========
 
-#define PANEL_H     150
-#define PANEL_GAP   16
+#ifdef BOARD_AMOLED_18
+// 368x448 portrait — compressed vertical layout so two panels + bottom anim
+// label fit without overlap.
+#define PANEL_H        130
+#define PANEL_GAP      12
+#define PANEL_BAR_Y    48
+#define PANEL_RESET_Y  78
+#else
+// 480x480 square (original)
+#define PANEL_H        150
+#define PANEL_GAP      16
+#define PANEL_BAR_Y    56
+#define PANEL_RESET_Y  94
+#endif
 
 // One Session/Weekly panel: big % label, pill on the right, bar, reset label.
 // Pill y=1: symmetric inside the panel — panel-outer-top → pill-top equals
-// pill-bottom → bar-top (pill height 42 + panel pad_top 12 + bar y=56).
+// pill-bottom → bar-top.
 static void make_usage_panel(lv_obj_t* parent, int y, const char* pill_text,
                              lv_obj_t** out_pct, lv_obj_t** out_pill,
                              lv_obj_t** out_bar, lv_obj_t** out_reset) {
@@ -240,13 +277,13 @@ static void make_usage_panel(lv_obj_t* parent, int y, const char* pill_text,
     *out_pill = make_pill(panel, pill_text);
     lv_obj_align(*out_pill, LV_ALIGN_TOP_RIGHT, 0, 1);
 
-    *out_bar = make_bar(panel, 0, 56, CONTENT_W - 32, 24);
+    *out_bar = make_bar(panel, 0, PANEL_BAR_Y, CONTENT_W - 32, 24);
 
     *out_reset = lv_label_create(panel);
     lv_label_set_text(*out_reset, "---");
     lv_obj_set_style_text_font(*out_reset, &font_styrene_28, 0);
     lv_obj_set_style_text_color(*out_reset, COL_DIM, 0);
-    lv_obj_set_pos(*out_reset, 0, 94);
+    lv_obj_set_pos(*out_reset, 0, PANEL_RESET_Y);
 }
 
 static void init_usage_screen(lv_obj_t* scr) {
@@ -279,7 +316,15 @@ static void init_usage_screen(lv_obj_t* scr) {
     lv_obj_align(lbl_anim, LV_ALIGN_BOTTOM_MID, 0, -15);
 }
 
-// ======== Bluetooth Screen (480x480) ========
+// ======== Bluetooth Screen ========
+
+#ifdef BOARD_AMOLED_18
+#define BT_INFO_PANEL_H   140
+#define BT_RESET_ZONE_H   90
+#else
+#define BT_INFO_PANEL_H   160
+#define BT_RESET_ZONE_H   110
+#endif
 
 static void init_bluetooth_screen(lv_obj_t* scr) {
     ble_container = lv_obj_create(scr);
@@ -293,12 +338,12 @@ static void init_bluetooth_screen(lv_obj_t* scr) {
     // Title
     lv_obj_t* lbl_ble_title = lv_label_create(ble_container);
     lv_label_set_text(lbl_ble_title, "Bluetooth");
-    lv_obj_set_style_text_font(lbl_ble_title, &font_tiempos_56, 0);
+    lv_obj_set_style_text_font(lbl_ble_title, &BT_TITLE_FONT, 0);
     lv_obj_set_style_text_color(lbl_ble_title, COL_TEXT, 0);
     lv_obj_align(lbl_ble_title, LV_ALIGN_TOP_MID, 16, TITLE_Y);
 
-    // Info panel (taller for 480x480)
-    lv_obj_t* p_info = make_panel(ble_container, MARGIN, CONTENT_Y, CONTENT_W, 160);
+    // Info panel
+    lv_obj_t* p_info = make_panel(ble_container, MARGIN, CONTENT_Y, CONTENT_W, BT_INFO_PANEL_H);
 
     // Bluetooth icon + status row
     static lv_image_dsc_t icon_bt_dsc;
@@ -310,27 +355,27 @@ static void init_bluetooth_screen(lv_obj_t* scr) {
 
     lbl_ble_status = lv_label_create(p_info);
     lv_label_set_text(lbl_ble_status, "Initializing...");
-    lv_obj_set_style_text_font(lbl_ble_status, &font_styrene_48, 0);
+    lv_obj_set_style_text_font(lbl_ble_status, &BT_STATUS_FONT, 0);
     lv_obj_set_style_text_color(lbl_ble_status, COL_DIM, 0);
     lv_obj_set_pos(lbl_ble_status, 56, 2);
 
     lbl_ble_device = lv_label_create(p_info);
     lv_label_set_text(lbl_ble_device, "Device: ---");
-    lv_obj_set_style_text_font(lbl_ble_device, &font_styrene_28, 0);
+    lv_obj_set_style_text_font(lbl_ble_device, &BT_DEVICE_FONT, 0);
     lv_obj_set_style_text_color(lbl_ble_device, COL_DIM, 0);
     lv_obj_set_pos(lbl_ble_device, 0, 64);
 
     lbl_ble_mac = lv_label_create(p_info);
     lv_label_set_text(lbl_ble_mac, "Address: ---");
-    lv_obj_set_style_text_font(lbl_ble_mac, &font_styrene_28, 0);
+    lv_obj_set_style_text_font(lbl_ble_mac, &BT_DEVICE_FONT, 0);
     lv_obj_set_style_text_color(lbl_ble_mac, COL_DIM, 0);
     lv_obj_set_pos(lbl_ble_mac, 0, 100);
 
     // Reset Bluetooth tap zone with trash icon
-    int reset_y = CONTENT_Y + 160 + 16;
+    int reset_y = CONTENT_Y + BT_INFO_PANEL_H + 16;
     lv_obj_t* reset_zone = lv_obj_create(ble_container);
     lv_obj_set_pos(reset_zone, MARGIN, reset_y);
-    lv_obj_set_size(reset_zone, CONTENT_W, 110);
+    lv_obj_set_size(reset_zone, CONTENT_W, BT_RESET_ZONE_H);
     lv_obj_set_style_bg_color(reset_zone, COL_PANEL, 0);
     lv_obj_set_style_bg_opa(reset_zone, LV_OPA_COVER, 0);
     lv_obj_set_style_radius(reset_zone, 8, 0);
@@ -348,19 +393,19 @@ static void init_bluetooth_screen(lv_obj_t* scr) {
 
     lv_obj_t* reset_lbl = lv_label_create(reset_zone);
     lv_label_set_text(reset_lbl, "Reset Bluetooth");
-    lv_obj_set_style_text_font(reset_lbl, &font_styrene_28, 0);
+    lv_obj_set_style_text_font(reset_lbl, &BT_DEVICE_FONT, 0);
     lv_obj_set_style_text_color(reset_lbl, COL_DIM, 0);
 
     // Attribution
     lv_obj_t* lbl_credit = lv_label_create(ble_container);
     lv_label_set_text(lbl_credit, "Built by @hermannbjorgvin");
-    lv_obj_set_style_text_font(lbl_credit, &font_styrene_24, 0);
+    lv_obj_set_style_text_font(lbl_credit, &BT_CREDIT_1_FONT, 0);
     lv_obj_set_style_text_color(lbl_credit, COL_DIM, 0);
     lv_obj_align(lbl_credit, LV_ALIGN_BOTTOM_MID, 0, -46);
 
     lv_obj_t* lbl_credit2 = lv_label_create(ble_container);
     lv_label_set_text(lbl_credit2, "Clawd animation by @amaanbuilds");
-    lv_obj_set_style_text_font(lbl_credit2, &font_styrene_20, 0);
+    lv_obj_set_style_text_font(lbl_credit2, &BT_CREDIT_2_FONT, 0);
     lv_obj_set_style_text_color(lbl_credit2, COL_DIM, 0);
     lv_obj_align(lbl_credit2, LV_ALIGN_BOTTOM_MID, 0, -20);