Document icon-probe results; keep iconfinder bitprobe as artifact

Probed remaining frame bytes for Bluetooth/power icons on a blank panel:
- found cross-wired glyph dots (byte0 bit7, byte4 bit7) and an I2C timeout
  (byte8 bit4), but no standalone icon bits
- waveshare reference does not drive these icons; likely multi-bit or
  unpopulated on the glass (cosmetic, deprioritized)
- restore temphummon.c as the active firmware build in CMakeLists

PROJECT_MEMORY.md

@@ -93,6 +93,20 @@ All three are **bit 5 (0x20) of the SECOND byte of the pair**, matching the manu
 | **Decimal point (bottom)** | `f[8]` | bit 5 (0x20) | after bottom-line **ones** → `88.8` |
 | **% sign (humidity)** | `f[10]` | bit 5 (0x20) | after bottom-line **tenths** → `88.8%` |
 
+### Bluetooth / power icons (probed — NOT found, likely multi-bit or unpopulated)
+
+A single-bit probe of the remaining frame bytes (0 bits5-7, 4/8/10 bits 4/6/7,
+14 all) found **no standalone Bluetooth or battery/power icon**.  Bits found:
+- byte 0 bit7 → a cross-wired glyph dot (top-ones region)
+- byte 4 bit7 → a cross-wired glyph dot (bottom-ones region)
+- byte 8 bit4 → caused an **I²C hardware timeout**
+- most other candidate bits → blank
+
+The Waveshare reference code does NOT drive any Bluetooth/power icon, and the
+IST7134 datasheet doesn't name one either.  Conclusion: if the icons exist on
+the glass they are **multi-bit patterns** (like °C = 0x05), not a simple single
+bit reachable by a bare frame write — not worth more bench time.  Cosmetic only.
+
 ### Verified glyph segment map (from probing)
 
 For a digit byte-pair, the **first byte** = left column + horizontal bars, the
@@ -259,6 +273,7 @@ nix run .#flash
 - [x] **Port Waveshare digit lookup table** — all 10 digits (0–9) verified working on the display
 - [x] **Internal temperature sensor** — reads ESP32-H2 internal temp sensor, shows on display line 1, updates every 1s
 - [x] **Find decimal point & % bits** — probing session mapped them: `f[4]/f[8]` bit5 = decimals, `f[10]` bit5 = %
+- [~] **Power/Bluetooth icons** — single-bit probe found no standalone icon bits; likely multi-bit patterns or unpopulated (cosmetic, deprioritized)
 - [ ] **Add humidity sensor** — wire up an external I²C sensor (SHT40, BME280, etc.) and show on display line 2
 - [ ] **Configure Matter/Thread** — enable OpenThread / Matter components in `sdkconfig`
 - [ ] **Implement Matter cluster** — temperature and humidity measurement clusters

firmware/main/bitprobe.c

@@ -1,14 +1,19 @@
 /**
- * dpfinder — ESP32-H2 Zero + 1.9" Segment E-Paper (IST7134 via I²C)
+ * iconfinder — ESP32-H2 Zero + 1.9" Segment E-Paper (IST7134 via I²C)
  *
- * Targeted decimal-point / % tester, guided by the manual:
+ * Hunt the POWER (battery) and BLUETOOTH icons.
- *   "The decimal point and % are the 5th place in the 4th, 8th, and 10th
+ * Per the manual: "13th position = °C/°F, 14th unused, and icons at other
- *    positions respectively."  (positions = vertical columns, L→R, T→B)
+ * positions" — we empirically probe the remaining untested frame bytes on a
+ * BLANK background (so a lone icon is unmistakable).
  *
- * We don't trust our model for exactly which BYTE is column 4/8/10, so we
+ * Bytes probed (0-indexed):
- * just test bit-5 (0x20) at a handful of candidate bytes on a clear display
+ *   byte 0 bits 5-7 (high bits we never tested; leading-1 glyph is 0-4)
- * (a few "8" digits for context) and the human reports which shows a decimal
+ *   byte 2 all 8     (second byte of top-tens pair)
- * point or %.
+ *   byte 6 all 8     (second byte of bottom-tens pair)
+ *   byte 13 bits 3-7 (after the C/F letter bits 0-2)
+ *   byte 14 all 8    (manual says unused, confirm)
+ * Dangerous black-control bits (byte 2 bit4, byte 4 bit7, byte 13 bit1)
+ * are SKIPPED to keep the panel stable.
  *
  * Wiring (GPIO4→SDA, GPIO5→SCL, GPIO10→RST, GPIO11→BUSY, 3V3→VCC, GND→GND)
  */
@@ -24,24 +29,13 @@
 #define PIN_SCL   GPIO_NUM_5
 #define PIN_RST   GPIO_NUM_10
 #define PIN_BUSY  GPIO_NUM_11
-
 #define PIN_BOOT  GPIO_NUM_9
 
 #define FRAME_LEN 15
-
 #define ADVANCE_MODE     1
 #define AUTO_HOLD_MS     3000
 #define BOOT_TIMEOUT_MS  0
 
-/* Digit "1" = minimal glyph (0x1f sets bits 0-4 only; bit 5 stays DARK so
- * an added bit-5 decimal point is clearly visible). */
-static const uint8_t DIG1[2] = {0x1f, 0x00};
-
-/* The 6 digit positions (byte pair). */
-static const uint8_t POS[6][2] = {
-    {1, 2}, {3, 4}, {5, 6}, {7, 8}, {9, 10}, {11, 12},
-};
-
 static i2c_master_bus_handle_t bus;
 static i2c_master_dev_handle_t cmd_dev, dat_dev;
 
@@ -101,18 +95,14 @@ static void epd_write(const uint8_t *frame, uint8_t extra_byte)
     i2c_master_transmit(cmd_dev, s, sizeof(s), pdMS_TO_TICKS(100));
 }
 
-/* Show a readout of "1"s (one in each position) + one extra bit.
+/* Show one bit of one byte on a BLANK background. */
- * Base "1" leaves bit5 dark, so a decimal/% bit at bit5 is clearly seen. */
+static void show_blank_plus(uint8_t frame_byte, uint8_t phys_bit, int tag)
-static void show_1s_plus(uint8_t frame_byte, uint8_t phys_bit, int tag)
 {
     uint8_t f[FRAME_LEN];
     memset(f, 0, FRAME_LEN);
-    for (int p = 0; p < 6; p++) {
-        f[POS[p][0]] = DIG1[0];
-        f[POS[p][1]] = DIG1[1];
-    }
     f[frame_byte] |= (uint8_t)(1u << phys_bit);
-    ESP_LOGI("dpfinder", "TEST %d: byte %d bit %d", tag, frame_byte, phys_bit);
+    ESP_LOGI("iconfinder", "T%d: byte %d bit %d (global %d)",
+             tag, frame_byte, phys_bit, frame_byte * 8 + phys_bit);
 
     uint8_t off[FRAME_LEN];
     memset(off, 0, FRAME_LEN);
@@ -122,14 +112,11 @@ static void show_1s_plus(uint8_t frame_byte, uint8_t phys_bit, int tag)
     epd_write(f, 0x00);
 }
 
-/* ------------------------------------------------------------------ */
 static void boot_init(void)
 {
     gpio_config_t bc = {
-        .pin_bit_mask = (1ULL << PIN_BOOT),
+        .pin_bit_mask = (1ULL << PIN_BOOT), .mode = GPIO_MODE_INPUT,
-        .mode = GPIO_MODE_INPUT,
+        .pull_up_en = GPIO_PULLUP_ENABLE, .pull_down_en = GPIO_PULLDOWN_DISABLE,
-        .pull_up_en = GPIO_PULLUP_ENABLE,
-        .pull_down_en = GPIO_PULLDOWN_DISABLE,
         .intr_type = GPIO_INTR_DISABLE,
     };
     gpio_config(&bc);
@@ -137,11 +124,8 @@ static void boot_init(void)
 
 static void wait_for_advance(void)
 {
-    if (ADVANCE_MODE == 0) {
+    if (ADVANCE_MODE == 0) { vTaskDelay(pdMS_TO_TICKS(AUTO_HOLD_MS)); return; }
-        vTaskDelay(pdMS_TO_TICKS(AUTO_HOLD_MS));
+    ESP_LOGI("iconfinder", "press BOOT to advance next...");
-        return;
-    }
-    ESP_LOGI("dpfinder", "press BOOT to advance next...");
     int64_t t_start = esp_timer_get_time();
     for (;;) {
         if (gpio_get_level(PIN_BOOT) == 0) {
@@ -152,7 +136,7 @@ static void wait_for_advance(void)
         }
         if (BOOT_TIMEOUT_MS > 0 &&
             esp_timer_get_time() - t_start > BOOT_TIMEOUT_MS * 1000LL) {
-            ESP_LOGW("dpfinder", "no BOOT press in %d ms, auto-advancing", BOOT_TIMEOUT_MS);
+            ESP_LOGW("iconfinder", "no BOOT press in %d ms", BOOT_TIMEOUT_MS);
             break;
         }
         vTaskDelay(pdMS_TO_TICKS(20));
@@ -192,32 +176,38 @@ void app_main(void)
     boot_init();
     epd_init();
 
-    ESP_LOGI("dpfinder", "== Test decimal/% at bit5 (0x20) of candidate bytes ==");
+    ESP_LOGI("iconfinder", "== Probe icon-region bytes on blank panel ==");
 
-    /* Phase 0: plain all 1s, no extra bit (reference). */
+    int tag = 0;
-    {
+
-        uint8_t f[FRAME_LEN];
+    /* byte 0 bits 5-7 (leading-1 glyph is bits 0-4; high bits unknown) */
-        memset(f, 0, FRAME_LEN);
+    for (int b = 5; b < 8; b++) { show_blank_plus(0, b, ++tag); wait_for_advance(); }
-        for (int p = 0; p < 6; p++) {
+
-            f[POS[p][0]] = DIG1[0];
+    /* byte 4 (top-ones second byte): we know bits 0-3 = glyph right col,
-            f[POS[p][1]] = DIG1[1];
+     * bit 5 = decimal.  The icon candidates are bits 4,6,7.  Probe those. */
-        }
+    for (int b = 4; b < 8; b++) {
-        uint8_t off[FRAME_LEN];
+        if (b == 5) continue;   /* decimal, already known */
-        memset(off, 0, FRAME_LEN);
+        show_blank_plus(4, b, ++tag); wait_for_advance();
-        epd_lut_GC(); epd_write(off, 0x00);
-        epd_lut_DU_WB(); epd_write(f, 0x00);
-        ESP_LOGI("dpfinder", "REF: all 1s (no extras)");
-        wait_for_advance();
     }
 
-    /* Bit 5 (=0x20) at each candidate byte, 0-indexed: 3,4,7,8,9,10 */
+    /* byte 8 (bottom-ones second byte): same reasoning, bits 4,6,7 */
-    const int cand_byte[] = {3, 4, 7, 8, 9, 10};
+    for (int b = 4; b < 8; b++) {
-    for (int i = 0; i < (int)(sizeof(cand_byte)/sizeof(cand_byte[0])); i++) {
+        if (b == 5) continue;   /* decimal, already known */
-        show_1s_plus(cand_byte[i], 5, i + 1);
+        show_blank_plus(8, b, ++tag); wait_for_advance();
-        wait_for_advance();
     }
 
-    ESP_LOGI("dpfinder", "== Done. ==");
+    /* byte 10 (bottom-tenths second byte): bits 4,6,7 (bit5=percent) */
+    for (int b = 4; b < 8; b++) {
+        if (b == 5) continue;   /* percent, already known */
+        show_blank_plus(10, b, ++tag); wait_for_advance();
+    }
+
+    /* byte 14 all bits (manual says unused - confirm) */
+    for (int b = 0; b < 8; b++) {
+        show_blank_plus(14, b, ++tag); wait_for_advance();
+    }
+
+    ESP_LOGI("iconfinder", "== Done. ==");
     uint8_t off[FRAME_LEN];
     memset(off, 0, FRAME_LEN);
     epd_lut_DU_WB();