Sorry if this is a long post, I'm trying to provide as much info as possible as I'm at a loss what to do (other than assume the boards are junk)
ISSUE:
Trying to use the Wifi capabilities of an ESP8266 and debugging in Serial monitor results in a reset loop and exception 0 error. Occurs with 10 / 10 of a batch of Clone D1 Minis recently received.
These are clone D1 Minis. issue doesn't occur when using an official Lolin Mini, or another clone ordered through other channels.
Wemos D1 Mini clones from Aliexpress, from following link:
https://www.aliexpress.com/item/32832670731.html?spm=a2g0o.productlist.0.0.2739393ecH2NEM&algo_pvid=e53f31b3-1f7c-465e-ba97-bfceaba8c746&algo_exp_id=e53f31b3-1f7c-465e-ba97-bfceaba8c746-0&pdp_ext_f={"sku_id"%3A"66938717676"}
Using a fresh install of the Arduino IDE (1.8.51.0)
Code such as Blink etc appears to work. But if I put a Serial.println in the blink loop, I get a little more garbage than normal thrown out at the start of the session (IE, normally you would see a few random characters instantly...and then the normal output. With these boards serial Monitor appears to write out junk characters for a few seconds and then normal text appears).
If I attempt to use the HelloServer example code, with the only modification being inputting my wifi SSID and password, I get the following error. This seems to happen no matter which "basic" example code I use.
(I've updated this thread to remove the original stack exception and just post the decoded exception information)
Exception 0: Illegal instruction
PC: 0x403060ff
EXCVADDR: 0x0000003a
Decoding stack results
0x40100bb8: umm_init() at D:\Documents\ArduinoData\packages\esp8266\hardware\esp8266\3.0.2\cores\esp8266\umm_malloc\umm_malloc.cpp line 476
0x401000ac: app_entry_redefinable() at D:\Documents\ArduinoData\packages\esp8266\hardware\esp8266\3.0.2\cores\esp8266\core_esp8266_main.cpp line 325
0x401003e8: ets_post(uint8, ETSSignal, ETSParam) at D:\Documents\ArduinoData\packages\esp8266\hardware\esp8266\3.0.2\cores\esp8266\core_esp8266_main.cpp line 181
0x401000c0: app_entry() at D:\Documents\ArduinoData\packages\esp8266\hardware\esp8266\3.0.2\cores\esp8266\core_esp8266_main.cpp line 331
And the HelloServer example code I'm using to troubleshoot.
#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <ESP8266WebServer.h>
#include <ESP8266mDNS.h>
#ifndef STASSID
#define STASSID "xxx"
#define STAPSK "xxx"
#endif
const char* ssid = STASSID;
const char* password = STAPSK;
ESP8266WebServer server(80);
const int led = 13;
void handleRoot() {
digitalWrite(led, 1);
server.send(200, "text/plain", "hello from esp8266!\r\n");
digitalWrite(led, 0);
}
void handleNotFound() {
digitalWrite(led, 1);
String message = "File Not Found\n\n";
message += "URI: ";
message += server.uri();
message += "\nMethod: ";
message += (server.method() == HTTP_GET) ? "GET" : "POST";
message += "\nArguments: ";
message += server.args();
message += "\n";
for (uint8_t i = 0; i < server.args(); i++) {
message += " " + server.argName(i) + ": " + server.arg(i) + "\n";
}
server.send(404, "text/plain", message);
digitalWrite(led, 0);
}
void setup(void) {
pinMode(led, OUTPUT);
digitalWrite(led, 0);
Serial.begin(115200);
WiFi.mode(WIFI_STA);
WiFi.begin(ssid, password);
Serial.println("");
// Wait for connection
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println("");
Serial.print("Connected to ");
Serial.println(ssid);
Serial.print("IP address: ");
Serial.println(WiFi.localIP());
if (MDNS.begin("esp8266")) {
Serial.println("MDNS responder started");
}
server.on("/", handleRoot);
server.on("/inline", []() {
server.send(200, "text/plain", "this works as well");
});
server.on("/gif", []() {
static const uint8_t gif[] PROGMEM = {
0x47, 0x49, 0x46, 0x38, 0x37, 0x61, 0x10, 0x00, 0x10, 0x00, 0x80, 0x01,
0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0x2c, 0x00, 0x00, 0x00, 0x00,
0x10, 0x00, 0x10, 0x00, 0x00, 0x02, 0x19, 0x8c, 0x8f, 0xa9, 0xcb, 0x9d,
0x00, 0x5f, 0x74, 0xb4, 0x56, 0xb0, 0xb0, 0xd2, 0xf2, 0x35, 0x1e, 0x4c,
0x0c, 0x24, 0x5a, 0xe6, 0x89, 0xa6, 0x4d, 0x01, 0x00, 0x3b
};
char gif_colored[sizeof(gif)];
memcpy_P(gif_colored, gif, sizeof(gif));
// Set the background to a random set of colors
gif_colored[16] = millis() % 256;
gif_colored[17] = millis() % 256;
gif_colored[18] = millis() % 256;
server.send(200, "image/gif", gif_colored, sizeof(gif_colored));
});
server.onNotFound(handleNotFound);
/////////////////////////////////////////////////////////
// Hook examples
server.addHook([](const String & method, const String & url, WiFiClient * client, ESP8266WebServer::ContentTypeFunction contentType) {
(void)method; // GET, PUT, ...
(void)url; // example: /root/myfile.html
(void)client; // the webserver tcp client connection
(void)contentType; // contentType(".html") => "text/html"
Serial.printf("A useless web hook has passed\n");
Serial.printf("(this hook is in 0x%08x area (401x=IRAM 402x=FLASH))\n", esp_get_program_counter());
return ESP8266WebServer::CLIENT_REQUEST_CAN_CONTINUE;
});
server.addHook([](const String&, const String & url, WiFiClient*, ESP8266WebServer::ContentTypeFunction) {
if (url.startsWith("/fail")) {
Serial.printf("An always failing web hook has been triggered\n");
return ESP8266WebServer::CLIENT_MUST_STOP;
}
return ESP8266WebServer::CLIENT_REQUEST_CAN_CONTINUE;
});
server.addHook([](const String&, const String & url, WiFiClient * client, ESP8266WebServer::ContentTypeFunction) {
if (url.startsWith("/dump")) {
Serial.printf("The dumper web hook is on the run\n");
// Here the request is not interpreted, so we cannot for sure
// swallow the exact amount matching the full request+content,
// hence the tcp connection cannot be handled anymore by the
// webserver.
#ifdef STREAMSEND_API
// we are lucky
client->sendAll(Serial, 500);
#else
auto last = millis();
while ((millis() - last) < 500) {
char buf[32];
size_t len = client->read((uint8_t*)buf, sizeof(buf));
if (len > 0) {
Serial.printf("(<%d> chars)", (int)len);
Serial.write(buf, len);
last = millis();
}
}
#endif
// Two choices: return MUST STOP and webserver will close it
// (we already have the example with '/fail' hook)
// or IS GIVEN and webserver will forget it
// trying with IS GIVEN and storing it on a dumb WiFiClient.
// check the client connection: it should not immediately be closed
// (make another '/dump' one to close the first)
Serial.printf("\nTelling server to forget this connection\n");
static WiFiClient forgetme = *client; // stop previous one if present and transfer client refcounter
return ESP8266WebServer::CLIENT_IS_GIVEN;
}
return ESP8266WebServer::CLIENT_REQUEST_CAN_CONTINUE;
});
// Hook examples
/////////////////////////////////////////////////////////
server.begin();
Serial.println("HTTP server started");
}
void loop(void) {
server.handleClient();
MDNS.update();
}
I'm wondering if there is a setting I need to change within the Arduino IDE. I've only recently moved from Arduino to ESP8266 and see there are many many options in the board manager. I'm using the default settings at the moment and taken a screenshot of what they are.
The supplier page doesn't list all the board specs, I know it'd be foolish to assume that the specs are an exact match for a genuine Lolin D1, but you'd hope that the same upload settings would work on them though?
I've tried changing the flash erase settings to both Sketch and Wifi, and All, but still have the same issue. ![D1 Settings|392x500]
The codes have been upploaded to just the boards with no sensors or peripherals attached.
Is there anything else I can try before getting in touch with the supplier?
See 
