firmware: add pH calibration NVS, protocol, and dispatch

main/eis.c

@@ -26,6 +26,8 @@ static struct {
 /* cell constant K (cm⁻¹), cached from NVS */
 static float cell_k_cached;
 static float cl_factor_cached;
+static float ph_slope_cached;
+static float ph_offset_cached;
 
 /* open-circuit calibration data */
 static struct {
@@ -594,8 +596,10 @@ int eis_has_open_cal(void)
     return ocal.valid;
 }
 
-#define NVS_CELLK_KEY    "cell_k"
+#define NVS_CELLK_KEY      "cell_k"
-#define NVS_CLFACTOR_KEY "cl_factor"
+#define NVS_CLFACTOR_KEY   "cl_factor"
+#define NVS_PH_SLOPE_KEY   "ph_slope"
+#define NVS_PH_OFFSET_KEY  "ph_offset"
 
 void eis_set_cell_k(float k)
 {
@@ -646,3 +650,31 @@ void eis_load_cl_factor(void)
         cl_factor_cached = 0.0f;
     nvs_close(h);
 }
+
+void eis_set_ph_cal(float slope, float offset)
+{
+    ph_slope_cached = slope;
+    ph_offset_cached = offset;
+    nvs_handle_t h;
+    if (nvs_open(NVS_OCAL_NS, NVS_READWRITE, &h) != ESP_OK) return;
+    nvs_set_blob(h, NVS_PH_SLOPE_KEY, &slope, sizeof(slope));
+    nvs_set_blob(h, NVS_PH_OFFSET_KEY, &offset, sizeof(offset));
+    nvs_commit(h);
+    nvs_close(h);
+}
+
+float eis_get_ph_slope(void)  { return ph_slope_cached; }
+float eis_get_ph_offset(void) { return ph_offset_cached; }
+
+void eis_load_ph_cal(void)
+{
+    nvs_handle_t h;
+    if (nvs_open(NVS_OCAL_NS, NVS_READONLY, &h) != ESP_OK) return;
+    size_t len = sizeof(ph_slope_cached);
+    if (nvs_get_blob(h, NVS_PH_SLOPE_KEY, &ph_slope_cached, &len) != ESP_OK || len != sizeof(ph_slope_cached))
+        ph_slope_cached = 0.0f;
+    len = sizeof(ph_offset_cached);
+    if (nvs_get_blob(h, NVS_PH_OFFSET_KEY, &ph_offset_cached, &len) != ESP_OK || len != sizeof(ph_offset_cached))
+        ph_offset_cached = 0.0f;
+    nvs_close(h);
+}

main/eis.h

@@ -71,4 +71,9 @@ void  eis_set_cl_factor(float f);
 float eis_get_cl_factor(void);
 void  eis_load_cl_factor(void);
 
+void  eis_set_ph_cal(float slope, float offset);
+float eis_get_ph_slope(void);
+float eis_get_ph_offset(void);
+void  eis_load_ph_cal(void);
+
 #endif

main/eis4.c

@@ -57,6 +57,7 @@ void app_main(void)
     eis_load_open_cal();
     eis_load_cell_k();
     eis_load_cl_factor();
+    eis_load_ph_cal();
     temp_init();
 
     esp_netif_init();
@@ -225,6 +226,16 @@ void app_main(void)
             send_cl_factor(eis_get_cl_factor());
             break;
 
+        case CMD_SET_PH_CAL:
+            eis_set_ph_cal(cmd.ph_cal.slope, cmd.ph_cal.offset);
+            send_ph_cal(cmd.ph_cal.slope, cmd.ph_cal.offset);
+            printf("pH cal set: slope=%.4f offset=%.4f\n", cmd.ph_cal.slope, cmd.ph_cal.offset);
+            break;
+
+        case CMD_GET_PH_CAL:
+            send_ph_cal(eis_get_ph_slope(), eis_get_ph_offset());
+            break;
+
         case CMD_START_CL: {
             ClConfig cl_cfg;
             cl_cfg.v_cond    = cmd.cl.v_cond;

main/protocol.c

@@ -303,6 +303,19 @@ int send_cl_end(void)
     return send_sysex(sx, sizeof(sx));
 }
 
+/* ---- outbound: pH calibration ---- */
+
+int send_ph_cal(float slope, float offset)
+{
+    uint8_t sx[16];
+    uint16_t p = 0;
+    sx[p++] = 0xF0; sx[p++] = 0x7D; sx[p++] = RSP_PH_CAL;
+    encode_float(slope, &sx[p]); p += 5;
+    encode_float(offset, &sx[p]); p += 5;
+    sx[p++] = 0xF7;
+    return send_sysex(sx, p);
+}
+
 /* ---- outbound: pH ---- */
 
 int send_ph_result(float v_ocp_mv, float ph, float temp_c)

main/protocol.h

@@ -28,6 +28,8 @@
 #define CMD_CLEAR_REFS    0x32
 #define CMD_SET_CL_FACTOR 0x33
 #define CMD_GET_CL_FACTOR 0x34
+#define CMD_SET_PH_CAL    0x35
+#define CMD_GET_PH_CAL    0x36
 
 /* Session sync commands (0x4x) */
 #define CMD_SESSION_CREATE  0x40
@@ -59,6 +61,7 @@
 #define RSP_REFS_DONE   0x22
 #define RSP_REF_STATUS  0x23
 #define RSP_CL_FACTOR   0x24
+#define RSP_PH_CAL      0x25
 
 /* Session sync responses (0x4x) */
 #define RSP_SESSION_CREATED  0x40
@@ -85,6 +88,7 @@ typedef struct {
         struct { float v_mv; float duration_s; } clean;
         float cell_k;
         float cl_factor;
+        struct { float slope; float offset; } ph_cal;
         struct { uint8_t name_len; char name[MAX_SESSION_NAME]; } session_create;
         struct { uint8_t id; } session_switch;
         struct { uint8_t id; uint8_t name_len; char name[MAX_SESSION_NAME]; } session_rename;
@@ -139,6 +143,9 @@ int send_cell_k(float k);
 /* outbound: chlorine factor */
 int send_cl_factor(float f);
 
+/* outbound: pH calibration */
+int send_ph_cal(float slope, float offset);
+
 /* outbound: reference collection */
 int send_ref_frame(uint8_t mode, uint8_t rtia_idx);
 int send_ref_lp_range(uint8_t mode, uint8_t low_idx, uint8_t high_idx);

main/wifi_transport.c

@@ -170,6 +170,11 @@ static void parse_udp_sysex(const uint8_t *data, uint16_t len)
         if (len < 8) return;
         cmd.cl_factor = decode_float(&data[3]);
         break;
+    case CMD_SET_PH_CAL:
+        if (len < 13) return;
+        cmd.ph_cal.slope  = decode_float(&data[3]);
+        cmd.ph_cal.offset = decode_float(&data[8]);
+        break;
     case CMD_SESSION_CREATE:
         if (len < 5) return;
         cmd.session_create.name_len = data[3] & 0x7F;
@@ -197,6 +202,7 @@ static void parse_udp_sysex(const uint8_t *data, uint16_t len)
     case CMD_GET_TEMP:
     case CMD_GET_CELL_K:
     case CMD_GET_CL_FACTOR:
+    case CMD_GET_PH_CAL:
     case CMD_START_REFS:
     case CMD_GET_REFS:
     case CMD_CLEAR_REFS: