Modify Cactus Micro:
http://blog.aprbrother.com/p/283
1) convert default serial port to hardware serial (cut/solder)
2) connect Digital pin 5 to ESP8266’s GPIO0 (so arduino sketch at the bottom of this page can pull ESP8266’s GPIO0 to GND – this puts the ESP8266 in program mode to receive firmware update)
Load Arduino programmer sketch – sends computer COM serial straight to ESP8266 hardware serial
https://github.com/volca/arduino_esp8266_programmer/blob/master/arduino_esp8266_programmer.ino
Flash firmware. Do NOT use esptool.py. I kept getting this error:
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Connecting... Traceback (most recent call last): File "./esptool.py", line 505, in <module> esp.connect() File "./esptool.py", line 158, in connect raise Exception('Failed to connect') Exception: Failed to connect |
Instead, use the GUI for Node MCU
http://randomnerdtutorials.com/flashing-nodemcu-firmware-on-the-esp8266-using-windows/
https://github.com/nodemcu/nodemcu-flasher
Click Config tab
Uncheck the internal Node MCU firmware (selected by default)
Browse for espduino 0x00000 bin
Browse for espduino 0x40000 bin
Enjoy espduino!
https://github.com/tuanpmt/espduino
Important: when using the serial passthrough Arduino sketch, don’t change the default baud rate of espduino – I tried to be smart and set it at 9600 — didn’t work.
Below is the “passthrough” sketch I used to stream the firmware from USB through Arduino serial through ESP8266 hardware serial. It’s ugly and there are many other similar sketches, but I’m saving the one I used here, just in case.
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/************************************************** * Simple pass-through serial flash programmer * programming the ESP8266 by an Arduino * * Any serial data is transfered as-is between the * two devices, with one exception: * Sending data to the Arduino will trigger a reset * of the ESP8266 into bootloader mode, if it is the * first connection attempt since 1 second. * If no data is send for 1 second, the ESP is reset * again into normal mode. * * This resembles the comfortable DTS controlled * programming mode one have with an FTDI or similiar * serial connection cable, where no manual reset of * the ESP is needed to upload code and run it. * Unfortunately there is no RTS/DTS control on the * Arduino Serial library, so we solely rely on timing. * * If the esptool does not wait or retry long enough, * you have to send some chars to trigger the reset * eg. add this to your Makefiles / scripts: * * echo 'RESET' >/dev/ttyACM0 * sleep 0.5 * esptool ..... * * * Transmissions from the ESP are passed without any * modification. * * You can not send serial commands (eg. to AT firmware) * to the ESP with this tool, as it would frequently * trigger resets into program mode. * * TODO: Provide control by magic keywords in the * serial data, like 'MAGIC_RESET_TO_BOOTLOADER'. * This way we can remove the timeouts and regain * interactive bidirectional serial console. * * TODO: tighten timings. * ***************************************************/ /* * Use an 3.3V Arduino, or TTL level shifter on RX / TX connections! * The pin 9 / 10 connections are just pulled down, no level shifter is needed here. * * connection table: * ESP8266 Arduino * GPIO0 5 * ENABLE 13 * RX TX * TX RX * GND GND * * Further connections to GND or VCC are needed depending on the ESP breakout module. * * An LED on Arduino Pin 13 would indicate Program Mode. */ int program_pin = 5; int enable_pin=13; //int led_pin=13; void setup() { delay(2000); Serial.println("setup ESP8266"); Serial1.begin(9600); Serial.begin(9600); pinMode(enable_pin, OUTPUT); pinMode(program_pin, OUTPUT); digitalWrite(program_pin, LOW); Serial.println("enabling ESP8266"); digitalWrite(enable_pin,HIGH); delay(10000); Serial.println("ESP8266 programmer ready."); } long last_send=0; // resets the ESP8266 into normal or program / bootloader mode void reset_target(bool program_mode) { return; if(program_mode) { pinMode(program_pin,OUTPUT); } else { pinMode(program_pin,INPUT); } //digitalWrite(led_pin, program_mode); delay(100); pinMode(enable_pin,INPUT); delay(100); pinMode(enable_pin,OUTPUT); digitalWrite(enable_pin,HIGH); delay(500); } bool program_mode=true; void loop() { while(Serial1.available()) { Serial.write((Serial1.read())); } // pass data from ESP to host, if any while(Serial1.available()) { Serial.write((uint8_t)Serial1.read()); } // pass data from host to ESP, if any if(Serial.available()) { // if we are not in program mode, trigger reset to bootloader mode. if(!program_mode){ //reset_target(true); program_mode=true; } // pass data while(Serial.available()) { Serial1.write((uint8_t)Serial.read()); } last_send=millis(); } // if the last transfer is more then one second ago, // trigger reset into normal mode. //if(last_send>0 && millis()-last_send>1000) if(0) { reset_target(false); last_send=0; program_mode=false; } } |
P.S. You’ll probably want this Arduino library next:
ArduinoJSON
https://github.com/bblanchon/ArduinoJson/wiki/Using%20the%20library%20with%20Arduino