Can anybody explain me some things about the ESP32?

[DummyForALife]

Hello!

I'm true to my name so I will have some really silly questions but this is the project I got in school.
I have to transmit pulses created by an ATmega128 (my plan is to wire ATmegas' UART1 RX/TX with ESPs UART0 RX/TX) but I'm not sure how to set the UART0 only to recieve (I found an example used in Arduino IDE but the best would be if I could write it myself). So where can I find an actual datasheet that has register names in it with some explanations on which bit does what etc.?
Another question is what to do to make it send out the information? I mean when I connect it with the ATmega128 and set the usart0 it will automatically send it out through wifi?
Thank you if you take your time to answer my questions!

[ESP_Dazz]

I have to transmit pulses created by an ATmega128 (my plan is to wire ATmegas' UART1 RX/TX with ESPs UART0 RX/TX) but I'm not sure how to set the UART0 only to recieve

Not sure if that's a good idea. UART0 is the default UART for all of the ESP32's log output. Therefore, by setting UART0 to receive only, you won't get any debug logs. Suggest you use UART1 instead.

So where can I find an actual datasheet that has register names in it with some explanations on which bit does what etc.?

See the UART Chapter of the ESP32 Technical Reference Manual. Better question is why you need to poke the hardware registers manually. UART drivers for ESP32 are well implemented in both Arduino (See Serial API) and ESP-IDF (See UART Driver API)

Another question is what to do to make it send out the information? I mean when I connect it with the ATmega128 and set the usart0 it will automatically send it out through wifi?

No. Sending data through WiFi is a completely different process. If you send data through UART (e.g. via a printf() in ESP-IDF or Serial.Write() in Arduino), it will transmit that data through UART0. How to send data via different UARTs, WiFi, BT, or any other medium will depend on whether you are writing your application using Arduino, or using ESP-IDF.

[PeterR]

Perhaps you are asking about the ESP32 AT firmware?

The ESP32 is a reprogrammable device which has UART, Wifi and other devices. You can write software which resides on the ESP which uses those devices.

There is already an Expressive 'AT' firmware program which configures the ESP32 as an AT modem device. An AT modem is a gateway from an RS232 host (PC, ATmega128, etc) to a Cell/Wifi network.
You would connect the ESP32 UART to another device's UART (e.g ATmega128). Then by sending AT text commands to the ESP you can tell the ESP to Wifi connect & transmit.
This way you only need to worry about the AT command set.
I have not used the ESP32 AT firmware but the AT command set is widely used and quite straight forward. You can play typing from a terminal.