Goodmorning, I'm working on a project for my studies in electronic engineering, I am looking at a PCB of a qr scanner and trying to debug it in order to use it with a microcontroller (esp32). The output of the scanner is usually taken from a usb port, but on the PCB there are also 4 others pin which I don't understand what they represent. The pins are 3.3V, GND (which are obvious), c and d. Anybody can explain me, in his opinion, c and d which protocol represent? (UART, I2c, ...). I know that it really depends on the design of the product, which has other purposes and it is hard to act on it, but maybe there is a suggestion from some hobbyist that encountered this problem.

I tried using it straight connected to the esp32 as if it uses a uart, but I was not lucky.

Attached a photo of the circuit

 

Hi 274,
They are most likely Clock and Data.
Do you have a part number for that PCB module?
E

 

Hi 274,
They are most likely Clock and Data.
Do you have a part number for that PCB module?
E

Thanks! I thought about it, so you think it refers to I2C?

I send you the photo of the whole PCB. The pins connected to 3.3V, GND, C and D have been connected by me, they were empty before.

 

Hi,
If this is a unit you purchased, what is the type number or name of the module?
E

 

Hi,
If this is a unit you purchased, what is the type number or name of the module?
E

Unfortunately I just bought a scanner from amazon and disassembled it, I give you the link but I know it's not what you need.

https://www.amazon.it/dp/B01FQTAOKA...JB4G3JQNEDM88DN1J&starsLeft=1&skipTwisterOG=2

If you have any suggestion, please hit me.

 

Hi Beso,
I checked through the link.
Why are you requiring to know the purpose of the C and D terminal pins, is it your intention to modify the unit?
E

 

Because I'm trying to use it with a microcontroller, I tried using the usb cable connected to a usb-uart adapter in order to read the barcodes with the esp32, but the unit does not work, with the pc works fine, but if I attach the esp32 it beeps in a strange way and doesn't work. I think the PC has a little bit of handshaking before working that I cannot control with the esp32, so I wanted to debug it from the PCB, you have other suggestions?