Added print messages to show progress.

And code to ensure the UART speed stayed at 74880 for a more complete viewing of messages. Well at least, it stays at 74880 for a longer time than it was. Added pinMode filter to prevent UART TX pin from being disabled during user_init().
esp8266 · mhightower83 · Dec 28, 2019 · Dec 30, 2019 · Dec 30, 2019 · Dec 30, 2019
commit 9c4e44bc8406eb3b4a7eab9260765f824e8b8749
diff --git a/cores/esp8266/Updater.cpp b/cores/esp8266/Updater.cpp
@@ -68,6 +68,9 @@ void UpdaterClass::_reset() {
 }
 
 bool UpdaterClass::begin(size_t size, int command, int ledPin, uint8_t ledOn) {
+  // Empty call so erase_config.cpp module to ensure it is built and linked in.
+  enable_erase_config_at_link_time();
+
   if(_size > 0){
 #ifdef DEBUG_UPDATER
     DEBUG_UPDATER.println(F("[begin] already running"));

diff --git a/cores/esp8266/core_esp8266_main.cpp b/cores/esp8266/core_esp8266_main.cpp
@@ -282,6 +282,17 @@ void init_done() {
    https://github.com/esp8266/Arduino/pull/4889
 
 */
+#if defined(ERASE_CONFIG_H)
+extern "C" void fix_divider(void);
+#define FIX_DIVIDER fix_divider
+#define ETS_PRINTF(...) ets_uart_printf(__VA_ARGS__)
+#define ETS_DELAY_US(a) ets_delay_us(a)
+#else
+#define FIX_DIVIDER() do {} while(0)
+#define ETS_PRINTF(...) do {} while(0)
+#define ETS_DELAY_US(a) do {} while(0)
+#endif
+
 
 extern "C" void app_entry_redefinable(void) __attribute__((weak));
 extern "C" void app_entry_redefinable(void)
@@ -291,6 +302,8 @@ extern "C" void app_entry_redefinable(void)
     cont_t s_cont __attribute__((aligned(16)));
     g_pcont = &s_cont;
 
+    FIX_DIVIDER();
+    ETS_PRINTF("\n\ncall_user_start()\n");
     /* Call the entry point of the SDK code. */
     call_user_start();
 }
@@ -312,7 +325,13 @@ extern "C" void user_init(void) {
     struct rst_info *rtc_info_ptr = system_get_rst_info();
     memcpy((void *) &resetInfo, (void *) rtc_info_ptr, sizeof(resetInfo));
 
+#if defined(ERASE_CONFIG_H)
+    uart_div_modify(0, UART_CLK_FREQ / (74880));
+    ETS_DELAY_US(150);
+    ETS_PRINTF("\nuser_init()\n");
+#else
     uart_div_modify(0, UART_CLK_FREQ / (115200));
+#endif
 
     init(); // in core_esp8266_wiring.c, inits hw regs and sdk timer
 

diff --git a/cores/esp8266/core_esp8266_postmortem.cpp b/cores/esp8266/core_esp8266_postmortem.cpp
@@ -89,7 +89,7 @@ static void ets_printf_P(const char *str, ...) {
     vsnprintf(destStr, sizeof(destStr), str, argPtr);
     va_end(argPtr);
     while (*c) {
-        ets_putc(*(c++));
+      ets_uart_putc1(*(c++));   // This will send "\r\n" for each '\n'
     }
 }
 
@@ -147,10 +147,10 @@ void __wrap_system_restart_local() {
     // (determined empirically, might break)
     uint32_t offset = 0;
     if (rst_info.reason == REASON_SOFT_WDT_RST) {
-        offset = 0x1b0;
+        offset = 0x190;
     }
     else if (rst_info.reason == REASON_EXCEPTION_RST) {
-        offset = 0x1a0;
+        offset = 0x180;
     }
     else if (rst_info.reason == REASON_WDT_RST) {
         offset = 0x10;

diff --git a/cores/esp8266/erase_config.cpp b/cores/esp8266/erase_config.cpp
@@ -58,10 +58,18 @@ OTAEraseConfig.
 #undef ERASE_CONFIG_H
 #endif
 
+#if 1
+#define ETS_PRINTF(...) ets_uart_printf(__VA_ARGS__)
+#define ETS_DELAY_US(a) ets_delay_us(a)
+#else
+#define ETS_PRINTF(...) do {} while(0)
+#define ETS_DELAY_US(a) do {} while(0)
+#endif
 
 #ifdef ERASE_CONFIG_H
 extern "C" {
 #include "user_interface.h"
+void __real_system_restart_local();
 
 #if   (ERASE_CONFIG_METHOD == 1)
 #define IRAM_MAYBE
@@ -71,7 +79,15 @@ extern "C" {
 #pragma GCC error "Unsupported ERASE_CONFIG_METHOD"
 #endif
 
-bool IRAM_MAYBE erase_config2(const uint32_t flash_erase_mask) {
+
+void enable_erase_config_at_link_time(void) {
+    /*
+      This has to be called from somewhere for this module to get
+      linked into the build.
+    */
+}
+
+bool IRAM_MAYBE erase_config(const uint32_t flash_erase_mask) {
     // This is really the active configured size
     uint32_t flash_size = flashchip->chip_size;
     uint32_t erase_mask = (flash_erase_mask & (uint32_t)ERASE_CONFIG_ALL_DATA);
@@ -84,7 +100,10 @@ bool IRAM_MAYBE erase_config2(const uint32_t flash_erase_mask) {
 #elif (ERASE_CONFIG_METHOD == 2)
             if (0 != SPIEraseSector(sector)) {
 #endif
+                ETS_PRINTF("Erase sector 0x%04X failed!\n", sector);
                 return false;
+            } else {
+                ETS_PRINTF("Erased sector 0x%04X\n", sector);
             }
         }
     }
@@ -114,18 +133,82 @@ bool IRAM_MAYBE check_and_erase_config(void) {
             ebcmd->args[i] = 0U;
 
         if (erase_flash_option) {
+            ETS_PRINTF("\nerase_config(0x%03X)\n", erase_flash_option);
 #if (ERASE_CONFIG_METHOD == 1)
-            erase_config2(erase_flash_option);
-            system_restart();
+            erase_config(erase_flash_option);
+            ETS_PRINTF("\n__real_system_restart_local\n\n");
+            ETS_DELAY_US(12000);
+            __real_system_restart_local();
             while(true){}
 #elif (ERASE_CONFIG_METHOD == 2)
-            return erase_config2(erase_flash_option);
+            return erase_config(erase_flash_option);
 #endif
         }
+    } else {
+        ETS_PRINTF("\nNo OTA erase flags\n");
+    }
+    return true;
+}
+
+
+
+
+typedef enum ROM_RST_REASON { /* Comments on the right are from RTOS SDK */
+  NO_MEAN                =  0,    /* Undefined */
+  POWERON_RESET          =  1,    /* Power on boot      *//**<1, Vbat power on reset */
+  EXT_RESET              =  2,    /* External reset or wake-up from Deep-sleep */
+                                                          /**<2, external system reset */
+  SW_RESET               =  3,    /*                    *//**<3, Software reset digital core */
+  OWDT_RESET             =  4,    /* Hardware WDT reset *//**<4, Legacy watch dog reset digital core */
+  DEEPSLEEP_RESET        =  5,    /*                    *//**<5, Deep Sleep reset digital core */
+  SDIO_RESET             =  6,    /*                    *//**<6, Reset by SLC module, reset digital core*/
+} ROM_RST_REASON_t;
+
+constexpr volatile uint32_t *RTC_SYS = (volatile uint32_t*)0x60001100;
+extern uint32_t rtc_get_reset_reason(void);
+
+bool ICACHE_RAM_ATTR is_cpu_freq_cal(void) {
+    const uint32_t rtc_sys_reason = RTC_SYS[0];
+    const uint32_t rom_api_reason = rtc_get_reset_reason();
+    if (1 >= rtc_sys_reason && OWDT_RESET != rom_api_reason) {
+      return false;  // REASON_EXT_SYS_RST
+    }
+    if (REASON_EXT_SYS_RST < rtc_sys_reason) {
+      return false;  // REASON_DEFAULT_RST
     }
     return true;
 }
 
+/*
+ * Here we use uart_div_modify in the Boot ROM. Note the Boot ROM version does
+ * not do any input validation.
+ *
+ * We cannot use the SDKs replacement. It is not in IRAM.
+ */
+#ifndef ROM_uart_div_modify
+#define ROM_uart_div_modify         0x400039d8
+#endif
+typedef void (*fp_uart_div_modify_t)(uint32_t uart_no, uint32 DivLatchValue);
+constexpr fp_uart_div_modify_t real_uart_div_modify = (fp_uart_div_modify_t)ROM_uart_div_modify;
+
+void ICACHE_RAM_ATTR fix_divider(void) {
+    /*
+      When reset cause is not power-on or EXT_RST the CPU crystal calibration
+      has been done and there is no need to correct. With the exception of some
+      early callback(s) from the SDK like run_user_rf_pre_init(). The UART speed
+      appears to always be based on the precalibrated crystal frequency.
+    */
+    uint32_t divider = UART_CLK_FREQ / 115200;
+    if (is_cpu_freq_cal()) {
+        divider = UART_CLK_FREQ / 74880;
+    }
+    real_uart_div_modify(0, divider);
+    ETS_DELAY_US(150);
+}
+
+
+
+
 
 #if (ERASE_CONFIG_METHOD == 1)
 extern struct rst_info resetInfo;
@@ -138,16 +221,15 @@ extern "C" void preinit (void)
     }
 }
 
-
-
 #elif (ERASE_CONFIG_METHOD == 2) //Another option
+
 #include "cont.h"
 
 int eboot_two_shots __attribute__((section(".noinit")));
 extern cont_t* g_pcont;
 extern "C" void call_user_start();
 
-extern "C" void app_entry_redefinable(void)
+extern "C" void ICACHE_RAM_ATTR app_entry_redefinable(void)
 {
     /* Allocate continuation context on this SYS stack,
        and save pointer to it. */
@@ -156,6 +238,10 @@ extern "C" void app_entry_redefinable(void)
 
     eboot_two_shots = 2;
 
+    fix_divider();
+    ETS_PRINTF("\n\ncall_user_start()\n");
+    ETS_DELAY_US(12000);
+
     /* Call the entry point of the SDK code. */
     call_user_start();
 }
@@ -182,15 +268,57 @@ int ICACHE_RAM_ATTR SPIRead(uint32_t addr, void *dest, size_t size) {
     // config sectors.
     if (eboot_two_shots) {
         eboot_two_shots--;
-        if (0 == eboot_two_shots)
+        if (0 == eboot_two_shots) {
+            fix_divider();
             check_and_erase_config();
+            ETS_DELAY_US(12000);
+        }
     }
 
     int err = real_SPIRead(addr, dest, size);
     dbg_log_SPIRead(addr, dest, size, err);
     return err;
 }
+
+
 #endif
 
 };
 #endif // ERASE_CONFIG_H
+
+
+extern "C" void ICACHE_RAM_ATTR _Z22__run_user_rf_pre_initv(void) {
+    // fix_divider();
+    real_uart_div_modify(0, UART_CLK_FREQ / 115200);
+    ETS_DELAY_US(150);
+    ets_uart_printf("\n__run_user_rf_pre_init()\n");
+    ETS_DELAY_US(12000);
+}
+
+/*
+  This helps keep the UART enabled longer so we can get a few more messages
+  printed.
+*/
+#if 1
+extern struct rst_info resetInfo;
+extern "C" void __pinMode( uint8_t pin, uint8_t mode );
+
+inline bool is_gpio_persistent(void) {
+  return REASON_EXCEPTION_RST <= resetInfo.reason &&
+         REASON_SOFT_RESTART  >= resetInfo.reason;
+}
+
+extern "C" void pinMode( uint8_t pin, uint8_t mode ) {
+  static bool in_initPins = true;
+  if (in_initPins && (1 == pin)) {
+    if (!is_gpio_persistent()) {
+      // Restore pin to TX after Power-on and EXT_RST
+      __pinMode(pin, FUNCTION_0);
+    }
+    in_initPins = false;
+    return;
+  }
+
+  __pinMode( pin, mode );
+}
+#endif
diff --git a/cores/esp8266/erase_config.h b/cores/esp8266/erase_config.h
@@ -36,6 +36,7 @@ ERASE_CONFIG_ALL_DATA     = (   BIT(4)  |  BIT(3)   |   BIT(2)  |   BIT(1)  |
 
 bool check_and_erase_config(void);
 bool erase_config(const uint32_t flash_erase_mask);
+void enable_erase_config_at_link_time(void);
 
 #ifdef __cplusplus
 };

diff --git a/libraries/ArduinoOTA/examples/OTAConfigErase/OTAConfigErase.ino b/libraries/ArduinoOTA/examples/OTAConfigErase/OTAConfigErase.ino
@@ -29,7 +29,7 @@ const char* password = STAPSK;
   ERASE_CONFIG_SDK_DATA
   ERASE_CONFIG_ALL_DATA
 */
-ERASE_CONFIG_MASK_t eraseConfigOption = ERASE_CONFIG_BLANK_BIN;
+ERASE_CONFIG_MASK_t eraseConfigOption = ERASE_CONFIG_RF_CAL; //ERASE_CONFIG_BLANK_BIN;
 
 #define String_F(a) String(F(a))
 
@@ -52,10 +52,11 @@ void setTimeTZ(String& tz) {
 }
 
 void setup() {
-  Serial.begin(115200);
+  Serial.begin(74880);
+  // Serial.begin(115200);
   delay(20);
   Serial.println();
-  Serial.println("Booting");
+  Serial.println("setup ...");
 
   WiFi.persistent(false); // w/o this a flash write occurs at every boot
   WiFi.mode(WIFI_OFF);
@@ -135,7 +136,7 @@ void setup() {
     }
   });
   ArduinoOTA.begin();
-  Serial.println("Ready");
+  Serial.println("setup complete");
   Serial.print("IP address: ");
   Serial.println(WiFi.localIP());
   Serial.println();