This project represents typical ESP8266 TCP Server application maintaining basic functionality to receive and process sample single-byte data from corresponding TCP Client side. Further data processing also consts of simple scenario to set GPIO12, GPIO13, GPIO14 output levels according to 3 less-significat bits from input byte of data.

This application allows to demonstrate basic data transfer concepts between ESP Client node and ESP Server node (over TCP protocol). This particular repository contains ESP8266 TCP Server side implementation (client side sample implementation is available at: https://github.com/sigma-prj/esp-tcp-client ).

The following topics are described and implemented within application's source code:

• How to open ESP server-side TCP socket under certain IP address
• How to setup server DHCP config with client-assignment addresses range
• How to accept connections on ESP server-side under specific port
• How to manage WiFi sessions (to set specific WiFi session name, WiFi security mode and WiFi password)

This application is targeted to be built under ESP8266_NONOS_SDK platform. Target ESP8266 NON OS SDK is available for downloading from https://www.espressif.com . Application repository project files can be placed to any subfolder under SDK root folder.

In order to build this project, the standard ESP SDK procedure can be followed. Build process can be triggered by execution of default target on a project's root Makefile with specific set of arguments.

Typical Makefile target execution sample and arguments set can be found at ESP SDK example:

[esp-sdk]/examples/peripheral_test/gen_misc.sh

Particular shell command and argumets may depends on a specific ESP board configuration. Below is the typical example to trigger build on a certain ESP configuration:

make COMPILE=gcc BOOT=none APP=0 SPI_SPEED=20 SPI_MODE=DIO SPI_SIZE_MAP=4 FLAVOR=release

This application also can be built with output debug UART logs enabled. For these purposes, special symbol UART_DEBUG_LOGS can be defined in build configuration:

make COMPILE=gcc BOOT=none APP=0 SPI_SPEED=20 SPI_MODE=DIO SPI_SIZE_MAP=4 FLAVOR=release UNIVERSAL_TARGET_DEFINES=-DUART_DEBUG_LOGS

Under scripts folder the following SH files are located:

scripts/erase_mem_non_ota_manual_rst.sh
scripts/flash_mem_non_ota_manual_rst.sh

These can be used to flash compiled binaries into ESP chip memory. Erase script also allows to clean-up ESP memory before flashing actual application. Once binaries are compiled, shell script can be triggered directly either it can be executed through corresponding Makefile targets:

# To erase ESP memory
make image_erase
# To flash actual application into ESP memory
make image_flash

Note: These scripts are coming with 'no_reset' option defined, suggesting that ESP chip needs to be reset manually before each erase\flash step. In case of ESP module is used with autoreset hardware feature - there is a need to remove corresponding 'no_reset' command line arguments within SH files.

Schema sample design and other additional information about this project can be found on the following URL:

http://www.sigmaprj.com/esp8266-tcp-client-server.html

This demo example suggests having 3 LEDs connected to corresponding GPIO PINs (12, 13, 14) in order to indicate the content of 3 less-significant bits received from input data byte.

Application demo video is also available at the following YouTube link (starting at 27:09):
https://www.youtube.com/watch?v=1Z2kSx1YNiA&t=1629

ESP8266 TCP Server Sample Application

Project is distributed under GNU GENERAL PUBLIC LICENSE 3.0

Copyright (C) 2021 - www.sigmaprj.com

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

ESPRESSIF MIT License

Copyright (c) 2015 <ESPRESSIF SYSTEMS (SHANGHAI) PTE LTD>

Permission is hereby granted for use on ESPRESSIF SYSTEMS ESP8266 only, in which case, it is free of charge, to any person obtaining a copy of this software and associated documentation files (the Software), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED AS IS, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.