ESP8266 / ESP-01 Serial Passthrough for serial console or flashing, using Arduino with SAMD MCU.
This Arduino sketch allows you to send AT commands, watch bootloader messages or flash an ESP-01/ESP8266 through a SAMD21/SAMD51 or similar MCU. The MCU used should be operating at 3.3V, if not, voltage level shifters must be used on the connections to ESP. The MCU should preferably also have native USB. The program might also work on other ESPs, but have only been tested with ESP8266 in the form of a ESP-01 board.
Developed and tested with a Arduino MKR board, SAMD21-based, with native USB connection to PC. The program might work on MCUs without native USB, but flashing must then be done at a fixed baudrate of 115200.
Sending AT commands has been tested using the Arduino serial monitor, Visual Micro serial monitor and PuTTY in serial mode. The same goes for watching bootloader output.
Firmware upgrade/flashing has been done with the official ESP8266 Flash Download Tool from https://www.espressif.com/en/support/download/other-tools, with firmware downloaded from https://www.espressif.com/en/support/download/at.
See guide in Wiki
Copyright 2021 Kåre Smith (Kaare Smith)
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
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