This is a ROM reader that is designed to be an easy to use, simple ROM dumping tool. It should be possible to send the dumper to someone in the post, have them plug a ROM in and get a dump of that ROM stored in the device flash. The device can then optionally dump more ROMs and then be sent back to the person who wants the dumps. The dumps are then extracted from the device flash.
*** NOTE: Make sure pin 1 of the ROM is correctly aligned with pin 1 on the socket when inserting it ***
The dumper can also dump ROM contents to the USB port it is powered by.
The dumper is basically just a Pico attached to a ROM socket with serial resistors. It is making use of the possible/probably 5V tolerance of its GPIO lines-*-. The control signals are attached through low value resistors as they drive the ROM and aren't subject to 5V. The data lines are 5V and come into the Pico though cowardly 28K resistors.
The firmware uses the USB serial port for interactions with the user. It uses the flash of the Pico for firmware and also has configuration data stored in part of the flash. ROM dumps stored in several 'slots' of 16K each so an external non-volatile device isn't needed. the USB serial has a menu system that can be entered at boot-up and used to set the non-volatile configuration data that determines how the dumper will work. Slots can be cleared etc and data dumped from the menu system.
The dumper can be set up to dump to USB or dump data to a flash slot using the configuration menu. When dumping to a slot the data is also dumped to USB. Once all slots are full the dumper will not over-write any slots with new dumps, but the device can still be used as a dumper with a USB data dump.
To delete the slots a menu option is used, and several hoops have to be jumped through.
There are a couple of counters that count the number of USB dumps that the dumper has taken and the number of slot dumps it has performed.
-*-I saw a post on the internet, which if it really is by Eben Upton, says that the Pico GPIOs are 5V tolerant, but not 5V5 tolerant as inputs.
See here:
https://hackaday.com/2022/09/25/pi-pico-w-does-pcmcia-gets-this-ibm-pc110-online/#comment-6516402