Programming many Atmega328p at once for mass production

Question

How can I program multiple ATmega328p at once?

Like, for example, the Arduino Uno. How do they program it for mass manufacturing production?

Answer 1

To program in-circuit, you can also use either a JTAG-Connector - as seen on the J-Link Mini, or an on-PCB connector - as you can see on this tinyK22 microprocessor that's used at my university quite a lot. You can see the connectors next to the "K20" and "K22" print. The cable to plug this in is fairly expensive, but it allows you to program a board that only has the 'connector' implemented on the PCB.

Rather than downloading through the IDE, you'd download using a standalone flashing program.

If your quantities are high enough, just as the others said, you'd use preprogrammed chips from the factory.

Answer 2

Arduino exposes all the pins needed for "high voltage" parallel programming on the pin headers. This is faster than ICSP and probably how they are programmed in production, unless pre-programmed chips are used.

However the terminals needed for ICSP are also available so for low volumn production that's an option too.

Answer 3

If you do high volume production, the boards are assembled and tested automatically, so you already have a production step where voltage is applied to the board at selected spots.

Programming the board at this stage is just a matter of connecting to the appropriate pads for half a second, that is barely noticeable compared to the time that is spent testing for soldering defects.

Answer 4

If you are using the original arduino uno type chip, you can swap the chips or even get a ZIF socket for easier insertion and removal

_{Image source: Universal Solder - CANADUINO ZIF Socket Programming Shield V2 for Arduino}

You can also pay atmel/supplier to program it for you