Transparent UART Bridge Between Atmega32 Microcontrollers Using ESP-07 Modules

Hi. I would like to upgrade my old stereo project in which the control is based on Atmega32 microcontrollers, more precisely I need wireless communication between the Amplifier and the Subwoofer i.e. between one atmega and the other. Both devices are already prepared to exchange data via UART. This involves commands on-off, louder, quieter, filter, phase and others - generally transmission in both directions. I also have 2 ESP-07 modules, to which the whole question refers and for which I have made TTL adapters. Is it possible to set up a transparent transmission via UART (Atmega->ESP->Router->ESP->Atmega, or bypassing the router) so that I don't have to use AT commands, because frankly speaking it complicates the whole situation a bit. I am a layman when it comes to ESP while I program atmegas in C.

I understand that all of this can be done using the Arduino environment?

mmaker wrote:

may I understand that all this can be done using the arduino environment?

.
You can write programs on the ESP in the Arduino IDE.

Hello I consider the topic closed. I managed to do it with the help of the tutorial and the appropriate code from the internet. Topic to be closed .

Interesting thread, many people will end up here in the future. Why don't you write more about this topic and include links to these guides and codes. Save others from searching.

In a nutshell for my ESP-07 module (but also for all ESPs) it looks like this:
1. we download the Arduino IDE to our computer from the link selecting the correct architecture for our computer.

2. We install the software. After installation, we run the Arduino program, click on File -> Preferences and in the field "Additional URLs to the board manager:" paste only the address of this link , confirm OK.

3. in the main window, select Tools -> Tile: "Arduino/Genuino Uno" menu. -> Board Manager... In the manager window, scroll through the list and look for the item "esp8266 by ESP8266 Community" as shown in the image:
.
After selecting the item, click Install.

4. after installation, go to the "Tools" menu, scroll down the list and select the "Generic ESP8266 Module" board. Click again on the "Tools" menu, which shows us a lot of settings for our module. I just selected the appropriate COM port.

Now we just need to paste the ready code into the main window of the programme and upload it to our module by short-circuiting GPIO0 to ground while applying voltage to the module. This way we enter the flashing mode. You also need to remember to connect TX and RX lines correctly, so crosswise .
I, to make my life easier, made a TTL level adapter with voltage converter and buttons to reset and flash the module. I used 2 USB to Serial adapters (one self-made on FT232RL and the other on PL2303) and both work ok.

The software you need, depending on the configuration you want, can be found at https://circuits4you.com/2018/01/01/esp-to-esp-communication/.

All you need to do is to copy the code, change the SSID to the one assigned by your router, password, port for UDP communication, IP/Broadcast address and set the baudrate for UART transmission. The disadvantage of this type of solution is that it can sometimes cut one or two characters from the beginning of a string, but it happened very rarely with me. Alternatively, you have to deal with it somehow on the target device.

Link to the Arduino IDE ESP8266 tutorial on Youtube:
https://www.youtube.com/watch?v=Ao5XcORsYxA

Interesting code for transmission. However, I don't know if it will work properly. At 9600 we have less than a character per 1ms, and the author has introduced a delay(20) into the code. This delay makes it possible to transmit a mere 50 characters per second. In my opinion, this delay is completely unnecessary. The speed will be "stabilised" by the UART anyway. The second problem is the extreme wastefulness of transmission - each UDP packet that contains many bytes necessary for transmission carries only one byte of information. In UDP, by default, there is no check as to whether a packet has arrived, and the code does not address this problem programmatically. If we know what we are exchanging, e.g. short sequences (several hundred bytes), it is much better to collect such a sequence and send it in one packet. We are then certain that the packet will arrive in full or not at all. You may even be tempted to acknowledge receipt of the packet and retransmit it.

Or perhaps such hc-12 moduls.