Persist accelerometer deadzone in NVS across reboots.

Each node saves its local deadzone on UART or ESP-NOW set; pod_settings loads and applies it after BMA456 init.

Co-authored-by: Cursor <cursoragent@cursor.com>

main/CMakeLists.txt

@@ -30,6 +30,7 @@ idf_component_register(
   "esp_now_proto.c"
   "bosch456.c"
   "board_input.c"
+  "pod_settings.c"
   "proto/uart_messages.pb.c"
   "proto/esp_now_messages.pb.c"
   "proto/pb_encode.c"

main/README.md

@@ -82,12 +82,14 @@ Powerpod uses the Bosch **BMA456H** (hearable) variant, not the generic `bma456w
 
 **Accel logging:** Samples are printed only when any axis changes by more than the **deadzone** (raw LSB) since the last logged sample (default **100**). This is a **software** filter on top of the sensor; it does not change BMA456 hardware thresholds.
 
+**Persistence:** The local deadzone is stored in the **`nvs`** partition (namespace `powerpod`, key `accel_dz`) via `pod_settings.c`. Each node (master or slave) keeps its own value across reboot. Loaded at boot after `init_bma456()`; saved when set locally (UART `client_id = 0`, `all_clients` on master, or ESP-NOW deadzone on a slave).
+
 **Configuration paths:**
 
 | Path | Effect |
 |------|--------|
-| UART `ACCEL_DEADZONE` with `client_id = 0` | `bma456_set_accel_deadzone()` on the local node |
-| ESP-NOW `SET_ACCEL_DEADZONE` | Same on a slave (no-op log path if sensor not installed) |
+| UART `ACCEL_DEADZONE` with `client_id = 0` | Set + save local deadzone |
+| ESP-NOW `SET_ACCEL_DEADZONE` | Set + save on the receiving slave |
 | `make gotool-deadzone-set DEADZONE=… CLIENT=0` | Host shortcut for local deadzone |
 
 **Logs:** `[BMA456] ACC X=… Y=… Z=…` when deadzone exceeded; `[BMA456] tap: single|double|triple` on interrupt.
@@ -440,6 +442,7 @@ Target: ESP32-S3. Close serial monitor on the UART adapter port before running `
 | `client_registry.c/h` | Registered slave table |
 | `bosch456.c/h` | BMA456H I2C driver, accel poll, tap INT, deadzone filter |
 | `board_input.c/h` | Taster GPIO12, LiPo ADC on GPIO1 / GPIO12 |
+| `pod_settings.c/h` | NVS persistence (accel deadzone, …) |
 | `led_ring.c/h` | LED ring (digit display, progress bar) |
 | `cmd_led_ring.c` | UART `LED_RING` progress command |
 | `proto/uart_messages.proto` | UART protocol schema |

main/cmd_accel_deadzone.c

@@ -3,6 +3,7 @@
 #include "cmd_accel_deadzone.h"
 #include "esp_log.h"
 #include "esp_now_comm.h"
+#include "pod_settings.h"
 #include "uart_cmd.h"
 
 static const char *TAG = "[ACCEL_DZ]";
@@ -19,6 +20,14 @@ static void reply(uint32_t deadzone, uint32_t client_id, bool success,
   uart_cmd_send(&response, TAG);
 }
 
+static void apply_local_deadzone(uint32_t deadzone) {
+  bma456_set_accel_deadzone(deadzone);
+  if (pod_settings_save_accel_deadzone(deadzone) != ESP_OK) {
+    ESP_LOGW(TAG, "deadzone %lu applied but not saved to NVS",
+             (unsigned long)deadzone);
+  }
+}
+
 static esp_err_t push_deadzone_to_slave(const client_info_t *client,
                                         uint32_t deadzone) {
   if (client == NULL) {
@@ -67,7 +76,7 @@ static void handle_accel_deadzone(const uint8_t *data, size_t len) {
       }
 
       if (bma456_is_ready()) {
-        bma456_set_accel_deadzone(req.deadzone);
+        apply_local_deadzone(req.deadzone);
       }
 
       ESP_LOGI(TAG, "set deadzone %lu via unicast to %u/%u slaves",
@@ -77,7 +86,7 @@ static void handle_accel_deadzone(const uint8_t *data, size_t len) {
     }
 
     if (req.client_id == 0) {
-      bma456_set_accel_deadzone(req.deadzone);
+      apply_local_deadzone(req.deadzone);
       ESP_LOGI(TAG, "set local deadzone %lu (no ESP-NOW; use -client or -all "
                     "for slaves)",
                (unsigned long)req.deadzone);

main/esp_now_comm.c

@@ -3,6 +3,7 @@
 #include "esp_now_comm.h"
 #include "led_ring.h"
 #include "ota_espnow.h"
+#include "pod_settings.h"
 #include "esp_now_proto.h"
 #include "esp_err.h"
 #include "esp_event.h"
@@ -13,7 +14,6 @@
 #include "esp_wifi.h"
 #include "freertos/FreeRTOS.h"
 #include "freertos/idf_additions.h"
-#include "nvs_flash.h"
 #include "ota_uart.h"
 #include <stdio.h>
 #include <string.h>
@@ -399,6 +399,10 @@ static void handle_slave_accel_deadzone(const uint8_t *master_mac,
            bma456_is_ready() ? "ok" : "not installed");
 
   bma456_set_accel_deadzone(cfg->deadzone);
+  if (pod_settings_save_accel_deadzone(cfg->deadzone) != ESP_OK) {
+    ESP_LOGW(TAG, "slave deadzone %lu applied but not saved to NVS",
+             (unsigned long)cfg->deadzone);
+  }
 }
 
 static void handle_client_presence(const alox_EspNowSlavePresence *presence,
@@ -607,17 +611,6 @@ static void master_discover_task(void *param) {
 }
 
 static esp_err_t init_wifi_stack(uint8_t channel) {
-  esp_err_t err;
-
-  err = nvs_flash_init();
-  if (err == ESP_ERR_NVS_NO_FREE_PAGES || err == ESP_ERR_NVS_NEW_VERSION_FOUND) {
-    ESP_ERROR_CHECK(nvs_flash_erase());
-    err = nvs_flash_init();
-  }
-  if (err != ESP_OK) {
-    return err;
-  }
-
   ESP_ERROR_CHECK(esp_netif_init());
   ESP_ERROR_CHECK(esp_event_loop_create_default());
 

main/pod_settings.c

@@ -0,0 +1,110 @@
+#include "pod_settings.h"
+#include "bosch456.h"
+#include "esp_log.h"
+#include "nvs.h"
+#include "nvs_flash.h"
+
+static const char *TAG = "[SETTINGS]";
+static const char *NS = "powerpod";
+static const char *KEY_ACCEL_DZ = "accel_dz";
+
+#define ACCEL_DEADZONE_MAX 4095u
+
+static bool s_nvs_ready;
+
+static esp_err_t ensure_nvs(void) {
+  if (s_nvs_ready) {
+    return ESP_OK;
+  }
+  return pod_settings_init();
+}
+
+esp_err_t pod_settings_init(void) {
+  if (s_nvs_ready) {
+    return ESP_OK;
+  }
+
+  esp_err_t err = nvs_flash_init();
+  if (err == ESP_ERR_NVS_NO_FREE_PAGES ||
+      err == ESP_ERR_NVS_NEW_VERSION_FOUND) {
+    ESP_LOGW(TAG, "NVS erase and re-init");
+    ESP_ERROR_CHECK(nvs_flash_erase());
+    err = nvs_flash_init();
+  }
+  if (err != ESP_OK) {
+    ESP_LOGE(TAG, "nvs_flash_init failed: %s", esp_err_to_name(err));
+    return err;
+  }
+
+  s_nvs_ready = true;
+  ESP_LOGI(TAG, "NVS ready, accel deadzone %lu LSB (stored)",
+           (unsigned long)pod_settings_load_accel_deadzone());
+  return ESP_OK;
+}
+
+uint32_t pod_settings_load_accel_deadzone(void) {
+  if (!s_nvs_ready) {
+    return BMA456_DEFAULT_ACCEL_DEADZONE;
+  }
+
+  nvs_handle_t handle;
+  esp_err_t err = nvs_open(NS, NVS_READONLY, &handle);
+  if (err != ESP_OK) {
+    return BMA456_DEFAULT_ACCEL_DEADZONE;
+  }
+
+  uint32_t value = BMA456_DEFAULT_ACCEL_DEADZONE;
+  err = nvs_get_u32(handle, KEY_ACCEL_DZ, &value);
+  nvs_close(handle);
+
+  if (err == ESP_ERR_NVS_NOT_FOUND) {
+    return BMA456_DEFAULT_ACCEL_DEADZONE;
+  }
+  if (err != ESP_OK) {
+    ESP_LOGW(TAG, "read accel_dz failed: %s", esp_err_to_name(err));
+    return BMA456_DEFAULT_ACCEL_DEADZONE;
+  }
+  if (value > ACCEL_DEADZONE_MAX) {
+    return BMA456_DEFAULT_ACCEL_DEADZONE;
+  }
+  return value;
+}
+
+esp_err_t pod_settings_save_accel_deadzone(uint32_t deadzone_lsb) {
+  if (deadzone_lsb > ACCEL_DEADZONE_MAX) {
+    return ESP_ERR_INVALID_ARG;
+  }
+
+  esp_err_t err = ensure_nvs();
+  if (err != ESP_OK) {
+    return err;
+  }
+
+  nvs_handle_t handle;
+  err = nvs_open(NS, NVS_READWRITE, &handle);
+  if (err != ESP_OK) {
+    ESP_LOGE(TAG, "nvs_open failed: %s", esp_err_to_name(err));
+    return err;
+  }
+
+  err = nvs_set_u32(handle, KEY_ACCEL_DZ, deadzone_lsb);
+  if (err == ESP_OK) {
+    err = nvs_commit(handle);
+  }
+  nvs_close(handle);
+
+  if (err != ESP_OK) {
+    ESP_LOGE(TAG, "save accel_dz failed: %s", esp_err_to_name(err));
+    return err;
+  }
+
+  ESP_LOGI(TAG, "saved accel deadzone %lu LSB", (unsigned long)deadzone_lsb);
+  return ESP_OK;
+}
+
+void pod_settings_apply_accel_deadzone(void) {
+  uint32_t deadzone = pod_settings_load_accel_deadzone();
+  if (bma456_is_ready()) {
+    bma456_set_accel_deadzone(deadzone);
+  }
+}

main/pod_settings.h

@@ -0,0 +1,19 @@
+#ifndef POD_SETTINGS_H
+#define POD_SETTINGS_H
+
+#include "esp_err.h"
+#include <stdint.h>
+
+/** Initialize NVS (idempotent) and log stored settings. Call once early in app_main. */
+esp_err_t pod_settings_init(void);
+
+/** Persist local accelerometer deadzone (LSB per axis). */
+esp_err_t pod_settings_save_accel_deadzone(uint32_t deadzone_lsb);
+
+/** Load deadzone from NVS, or BMA456_DEFAULT_ACCEL_DEADZONE if unset. */
+uint32_t pod_settings_load_accel_deadzone(void);
+
+/** Apply NVS deadzone to BMA456 when the sensor is present. */
+void pod_settings_apply_accel_deadzone(void);
+
+#endif

main/powerpod.c

@@ -22,6 +22,7 @@
 #include "board_input.h"
 #include "bosch456.h"
 #include "led_ring.h"
+#include "pod_settings.h"
 #include "uart.h"
 #include <stdint.h>
 
@@ -66,6 +67,10 @@ uint8_t reverse_high_nibble_lut(uint8_t n) {
 }
 
 void app_main(void) {
+  if (pod_settings_init() != ESP_OK) {
+    ESP_LOGW(TAG, "settings NVS init failed; using defaults");
+  }
+
   // Get Master Mode Pin
   gpio_reset_pin(DIP_MASTER);
   gpio_set_direction(DIP_MASTER, GPIO_MODE_INPUT);
@@ -125,6 +130,8 @@ void app_main(void) {
     esp_err_t bma_err = init_bma456(bus_handle);
     if (bma_err != ESP_OK) {
       ESP_LOGI(TAG, "BMA456 init skipped: %s", esp_err_to_name(bma_err));
+    } else {
+      pod_settings_apply_accel_deadzone();
     }
   }