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Finding Pin on MCU

I am fairly new to programming MCU. I have an ATtiny2313 and the datasheet came with a layout of how the pins are configured; however, finding pin 1, since the mcu is a square, is tough for me. I share the images of the diagram and the actual unit. Maybe I am overthinking the issue? Further reading materials are also greatly appreciated.

This is the datasheets diagram

This is the actual unit enter image description here

Solution

  • Check the Packaging information section at the end of datasheet. There are physical properties of packages described including any marking to identify pin 1.

    ATtiny2313 package

    In some situations (some really small ICs) it can be hard to identify right pin 1 marking. In production, one simply rely on orientation of chip in the tape, but for populating boards by hand, little trick can come handy anytime you are not sure, you have identified pin 1 correctly.

    In virtually any IC, there are ESD protection diodes from GND to any IO pin and prom IO pin to power rail. So, if you put a multimeter in diode measuring mode, you should see a drop about 700 mV (actual value can vary) when the positive probe is touching a ground pin and the negative probe any data pin, or when the negative probe is touching a positive voltage rail pin and the positive probe any IO pin. It is not 100 % fail-proof way, but really good and useful hint.