Hi, I'm trying to automate programming Atmega328p on a PCB. I don't want to plug it into PC and click upload on IDE every time. I would like to use pogo pins, press ONE button and have an arduino upload a pre-compiled hex with boot loader to the Atmega328p on the board. How can I go about it? Is it possible?
http://www.crossroadsfencing.com/BobuinoRev17/
Search on the above page for "standalone programmer".
This looks like exactly what I need but it's not open source 
Actually, seems this is the original: Gammon Forum : Electronics : Microprocessors : Atmega chip stand-alone programmer to upload .hex files
If this is huge number, as your other posts seem to imply, e.g. PAID - Need to scan QR code and upload to EEPROM. - Jobs and Paid Consultancy - Arduino Forum, then you could get the distributor of the ATMega328p chips have your custom software preloaded on the chips. I have no idea about the costs, or the minimum order quantity, though.
Yes, I've actually reached out to digikey and got some quotes, it's fairly expensive for the quantity I'm doing to justify. Faster to do it with a jig and a standalone programmer such as this. Except I can't seem to find the source code for a board similar to crossroad's one. I need to read more in depth Gammon's posts to figure it all out.
Seems Adafruit has a similar one too. Amazing what you can google when you know the right keywords to look up 
Standalone AVR ISP Programmer Shield Kit - includes blank chip! : ID 462 : $17.50 : Adafruit Industries, Unique & fun DIY electronics and kits