seems like it works; later TODO: add USART for RS232

F1:F103/AS3935-lightning/flash.h

@@ -0,0 +1,67 @@
+/*
+ * This file is part of the as3935 project.
+ * Copyright 2026 Edward V. Emelianov <edward.emelianoff@gmail.com>.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include "hardware.h" // for SENSORS_AMOUNT
+
+#define FLASH_SIZE_REG      ((uint32_t)0x1FFFF7E0)
+#define FLASH_SIZE          *((uint16_t*)FLASH_SIZE_REG)
+
+// maximal size (in letters) of iInterface for settings
+#define MAX_IINTERFACE_SZ   (16)
+
+typedef struct{
+    // t_afe_gain
+    uint8_t AFE_GB : 5;
+    // t_threshold
+    uint8_t WDTH : 4;
+    uint8_t NF_LEV : 3;
+    // t_lightning_reg
+    uint8_t SREJ : 4;
+    uint8_t MIN_NUM_LIG : 2;
+    // t_int_mask_ant
+    uint8_t MASK_DIST : 1;
+    uint8_t LCO_FDIV : 2;
+    // t_tun_disp
+    uint8_t TUN_CAP : 4;
+} sens_pars_t;
+
+typedef struct{
+    uint8_t restore : 1;   // restore sensors' parameters on start
+} flags_t;
+
+/*
+ * struct to save user configurations
+ */
+typedef struct __attribute__((packed, aligned(4))){
+    uint16_t userconf_sz;       // "magick number"
+    uint16_t iInterface[MAX_IINTERFACE_SZ]; // interface name
+    uint8_t iIlength;                       // length in symbols
+    sens_pars_t spars[SENSORS_AMOUNT];      // sensors' stored flags
+    flags_t flags;                          // common flags
+} user_conf;
+
+extern uint32_t maxCnum;
+extern user_conf the_conf;
+extern int currentconfidx;
+
+void flashstorage_init();
+int store_userconf();
+int erase_storage(int npage);