What is this circuit named and is there any possibility to put code on it? I got it out of a a led control box: https://www.aliexpress.com/item/1005001800237822.html
Custom PCB. You could contact the manufacturer for info, but the chances are essentially zero that there will be a response.
A lot would depend on what device U4 is. I would guess that U2 is probably a USB-serial chip - maybe one of the CH340 devices.
Are there any markings on the chips - especially U4.
EDIT: The L32+48 on the silkscreen could be referring to the 32 pin and 48 pin packages of U3 and U4. The board could have been designed for one of two different microcontroller devices.
Well, since the ISP connector is missing and the adjacent U3 is missing, doing anything software-wise doesn't seem possible.
If we guess that the (empty) 32-pin pad is for an ATmega 48/88/168/328:
The crystal pins are in the right place (pins 7 and 8)
The first ISP pin goes to Ground (pin 29)
The 6th ISP pin goes to SCLK (pin 17)
If you look at the bottom of the board you could trace the +5V, MOSI, MISO, and RESET pins. Knowing the ISP layout you could hook it up to an Arduino ISP and try to upload a sketch. Just treat it as an UNO and the verbose upload messages tell you what the chip's signature it. If that works it will tell you what that 48-pin chip is.
@urmom64 if you can upload a picture of the bottom of the board, then we could hazard a guess at the pinout of the ISP connector.
I think the guess by @johnwasser that the U3 is for one of the ATMega chips is pretty sound.
Looking at the ISP header, the top pin (the square one) routes to pin 29, which on my 328P datasheet is the RESET pin. As John points out, the bottom pin on the ISP header routes to pin 17, which is SCK. Pin 5 on the ISP header looks like it's connected to the copper fills, so likely GND.
A view of the rear of the board would likely show where MOSI & MISO (and maybe a 5V line) are.
After that, as John says, once you can get the device signature, you will know what chip you are dealing with.
I don't think U3 is ATMega. The power pins do not match.
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