In this thread we build the projects that others have shared - PicoRom is a DIP32 ROM/EPROM emulator that you can program on the fly with a USB cable

[hatmoose]

PicoRom is a DIP32 form-factor ROM emulator - up to 2Mbit in size and 70ns access speed



Github page here
https://github.com/wickerwaka/PicoROM

and cool writeup here
https://hackaday.com/2024/11/05/picorom-a-dip-32-8-bit-rom-emulator/

PicoRom does a bunch of cool tricks, but the coolest one (for me) is being able to connect via USB and push arbitrary data to it on the fly. My main use case for this is goofing off with NeoGeo carts but lots of other arcade hardware uses the Dip32 for various weird and wonderful EPROMS that are becoming hard to get or inconvenient to program.

You can buy one of these, tested, working and fully assembled for $28 which (as we will see in a moment) is an insanely good deal. So if you just want one that works, buy from here https://www.tindie.com/products/pbretro/picorom/

But - if you're like me and have to everything the hard way, then you're in the right place

 

[hatmoose]

Version 1.7 (the most recent) is a 6 layer board - normally these are hilariously expensive to produce but JLCPCB currently have a promo for $30 off 6-layer boards so I applied that.


Unfortunately these boards are not particularly cost effective for PCB assembly - they are dual sided, and have many components that are "basic" rather than "standard". And several of the components were out of stock when I ran the job. So plan B is hand soldering and hot air.

 

[hatmoose]

This is the cart that I ordered for parts - given that the whole thing needs to fit into a DIP32 package there are a lot of exceptionally tiny parts in here.
https://www.digikey.co.nz/short/55wfn8h8

SMD 0201 is roughly .5mm x .3mm
even placing these by hand requires a good microscope and expensive tweezers. To solder them its either a proper micro-iron or hot air.

It was about this time that I realised I had forgotten to order the stencil when I placed the order for the boards...