fix(plip): SLIC hook polarity active-LOW (K50835F open-collector) + faithful PD open-drain

plip_voice/main/board_config.h

@@ -43,7 +43,7 @@
 
 /* ---------- SLIC K50835F / AG1171-class front-end (A1S board wiring) ---------- */
 /* KEY3=GPIO19, KEY4=GPIO23, KEY5=GPIO18, KEY6=GPIO5 share these pins — reassigned to SLIC */
-#define PLIP_SLIC_RM    18   /* Ring Mode output — HIGH = ring burst active       */
+#define PLIP_SLIC_RM    18   /* Ring Mode output — HIGH = ring burst active */
 #define PLIP_SLIC_FR    5    /* Forward/Reverse output — toggled at 25 Hz for bell */
-#define PLIP_SLIC_SHK   23   /* Switch Hook input  — HIGH = off-hook (active-high) */
-#define PLIP_SLIC_PD    19   /* Power Down (open-drain) — HIGH = SLIC active       */
+#define PLIP_SLIC_SHK   23   /* Switch Hook input  — active-LOW (K50835F open-collector) */
+#define PLIP_SLIC_PD    19   /* Power Down (open-drain) — HIGH = SLIC active */

plip_voice/main/slic.c

@@ -20,10 +20,11 @@
 
 #define TAG "slic"
 
-/* Active-high hook polarity: HIGH on SHK = off-hook.
- * Source: hardware/projects/slic-phone/src/config/A252ConfigStore.cpp:262
- *   cfg.hook_active_high = true; */
-#define SLIC_SHK_OFFHOOK_LEVEL  1
+/* K50835F SHK is OPEN-COLLECTOR ACTIVE-LOW: the SLIC pulls SHK LOW when the
+ * loop is closed (off-hook) and releases it (pull-up → HIGH) when on-hook.
+ * So off-hook = LOW. (A252 used active-high via an external inverter; the A1S
+ * wires SHK straight to the GPIO, so the raw polarity is active-low.) */
+#define SLIC_SHK_OFFHOOK_LEVEL  0
 
 static volatile bool s_ringing = false;
 static TaskHandle_t  s_ring_task = NULL;
@@ -88,23 +89,15 @@ esp_err_t slic_init(void)
     ret = gpio_config(&shk_cfg);
     if (ret != ESP_OK) return ret;
 
-    /* PD: Power Down — push-pull output HIGH = SLIC active (definite power-up).
-     * Previous config (open-drain HIGH) left the line floating when no pull-up
-     * is present on the bench, keeping the SLIC in power-down.
-     * Push-pull HIGH drives the PD pin firmly high regardless of external resistors. */
-    gpio_config_t pd_cfg = {
-        .pin_bit_mask = (1ULL << PLIP_SLIC_PD),
-        .mode         = GPIO_MODE_OUTPUT,         /* push-pull (pas OD) */
-        .pull_up_en   = GPIO_PULLUP_DISABLE,
-        .pull_down_en = GPIO_PULLDOWN_DISABLE,
-        .intr_type    = GPIO_INTR_DISABLE,
-    };
-    ret = gpio_config(&pd_cfg);
+    /* PD: Power Down — EXACT A252-proven sequence: open-drain output, HIGH = released
+     * = SLIC active (setPowerDown(false) in Ks0835SlicController). This is the config
+     * the working Arduino slic-phone project uses on the same chip. */
+    ret = gpio_set_direction(PLIP_SLIC_PD, GPIO_MODE_OUTPUT_OD);
     if (ret != ESP_OK) return ret;
-    ret = gpio_set_level(PLIP_SLIC_PD, 1);   /* HIGH franc = SLIC actif */
+    ret = gpio_set_level(PLIP_SLIC_PD, 1);   /* open-drain released HIGH = active (A252-proven) */
     if (ret != ESP_OK) return ret;
 
-    ESP_LOGI(TAG, "slic: PD GPIO%d push-pull HIGH (SLIC power-up, franc)", PLIP_SLIC_PD);
+    ESP_LOGI(TAG, "slic: PD GPIO%d open-drain HIGH (A252-proven active) — testing with fixed mic", PLIP_SLIC_PD);
     ESP_LOGI(TAG, "slic: pins RM=%d FR=%d SHK=%d PD=%d hook_active_high=1",
              PLIP_SLIC_RM, PLIP_SLIC_FR, PLIP_SLIC_SHK, PLIP_SLIC_PD);
 

plip_voice/sdkconfig.defaults

@@ -37,7 +37,7 @@ CONFIG_FREERTOS_IDLE_TASK_STACKSIZE=2048
 
 # SLIC hook GPIO — SHK on GPIO23 (A1S KEY4, active-HIGH: HIGH = off-hook)
 CONFIG_PLIP_HOOK_GPIO=23
-CONFIG_PLIP_HOOK_ACTIVE_HIGH=y
+CONFIG_PLIP_HOOK_ACTIVE_HIGH=n
 
 # WiFi credentials — set via `idf.py menuconfig` (PLIP Voice Configuration)
 # or override locally in sdkconfig (NOT committed).