append `reset dfu` command and `CONFIG` -> `ENTER DFU`

NANOVNA_STM32_F072/board.c

@@ -70,6 +70,17 @@ const PALConfig pal_default_config = {
  * any other initialization.
  */
 void __early_init(void) {
+  if ( *((unsigned long *)BOOT_FROM_SYTEM_MEMORY_MAGIC_ADDRESS) == BOOT_FROM_SYTEM_MEMORY_MAGIC ) {
+    // require irq
+    __enable_irq();
+    *((unsigned long *)BOOT_FROM_SYTEM_MEMORY_MAGIC_ADDRESS) = 0;
+    // remap memory. unneeded for F072?
+    // RCC->APB2ENR |= RCC_APB2ENR_SYSCFGEN;
+    // SYSCFG->CFGR1 = 0x01;
+    __set_MSP(SYSTEM_BOOT_MSP); 
+    ( (void (*)(void)) (*((uint32_t *)(STM32F072xB_SYSTEM_MEMORY+4))) )();
+  }
+
   //si5351_setup();
   stm32_clock_init();
 }

NANOVNA_STM32_F072/board.h

@@ -40,6 +40,11 @@
  */
 #define STM32F072xB
 
+#define STM32F072xB_SYSTEM_MEMORY 0x1FFFC800
+#define BOOT_FROM_SYTEM_MEMORY_MAGIC_ADDRESS 0x20003FF0
+#define BOOT_FROM_SYTEM_MEMORY_MAGIC 0xDEADBEEF
+#define SYSTEM_BOOT_MSP 0x20002250
+
 /*
  * IO pins assignments
  */

main.c

@@ -120,6 +120,14 @@ static void cmd_reset(BaseSequentialStream *chp, int argc, char *argv[])
     (void)argc;
     (void)argv;
 
+    if (argc == 1) {
+        if (strcmp(argv[0], "dfu") == 0) {
+            chprintf(chp, "Performing reset to DFU mode\r\n");
+            enter_dfu();
+            return;
+        }
+    }
+
     chprintf(chp, "Performing reset\r\n");
 
     rccEnableWWDG(FALSE);

nanovna.h

@@ -339,6 +339,7 @@ void handle_touch_interrupt(void);
 
 void touch_cal_exec(void);
 void touch_draw_test(void);
+void enter_dfu(void);
 
 /*
  * adc.c

ui.c

@@ -414,6 +414,22 @@ show_version(void)
   touch_start_watchdog();
 }
 
+void
+enter_dfu(void)
+{
+  adc_stop(ADC1);
+
+  int x = 5, y = 5;
+
+  ili9341_fill(0, 0, 320, 240, 0);
+  ili9341_drawstring_5x7("DFU: Device Firmware Update Mode", x, y += 10, 0xffff, 0x0000);
+  ili9341_drawstring_5x7("To exit DFU, please reset device yourself.", x, y += 10, 0xffff, 0x0000);
+
+  // see __early_init in NANOVNA_STM32_F072/board.c
+  *((unsigned long *)BOOT_FROM_SYTEM_MEMORY_MAGIC_ADDRESS) = BOOT_FROM_SYTEM_MEMORY_MAGIC;
+  NVIC_SystemReset();
+}
+
 
 // type of menu item 
 enum {
@@ -525,6 +541,8 @@ menu_config_cb(int item)
       redraw_frame();
       request_to_redraw_grid();
       draw_menu();
+  case 4:
+      enter_dfu();
   }
 }
 
@@ -903,6 +921,7 @@ const menuitem_t menu_config[] = {
   { MT_CALLBACK, "TOUCH TEST", menu_config_cb },
   { MT_CALLBACK, "SAVE", menu_config_cb },
   { MT_CALLBACK, "VERSION", menu_config_cb },
+  { MT_CALLBACK, "ENTER DFU", menu_config_cb },
   { MT_CANCEL, S_LARROW" BACK", NULL },
   { MT_NONE, NULL, NULL } // sentinel
 };