What would your ideal upgrade be right now for your Amiga(s)

[Belial6]

Well, you know the other problem for high speed USB is that it is very interrupt heavy. When transferring large amounts of data from one high speed USB hard drive to another on my PC, I can track the interrupt overhead by watching /proc/interrupts. Servicing said interrupts ties up the CPU, which on linux shows up as abnormal amounts "%sy" (system) CPU.

So, even assuming we had a fast enough bus to put a high speed USB2 controller on, we'd probably find that the classic amiga hardware can't service the interrupts fast enough to get it going at full speed (high speed ethernet has the same problem too, but the packets are bigger and therefore fewer are generated per unit of data transferred).

I have thought about this, as a side note of thinking about USB Mice and Keyboards for my MiniMig.  I would think that a fairly cheap Arm processor could handle the USB stack and then interface to the Amiga in whatever protocol the Amiga could handle.  The idea being that to the Amiga it looks like a standard disk drive, and to the USB device it would look like an Arm computer.  Using this method you could use 100% of the the processor for the USB stack and interface to the Amiga, as that is the only task the Arm processor would be responsible for.  This would be useful for interfacing USB hard drives, USB keyboards, and USB mice.

[Belial6]

Exactly.  The Rasbarry Pi already supports USB 2.0, so we know that it can handle that.  Add the interfaces for connection to an Amiga (or other retro system) and your ready to go.

[Belial6]

I have been thinking about something like this... maybe using the Propeller chip as controller. The trick would be connecting to the Amiga. Do the ARM chips have the old school address & data bus interface to memory, or just SPI? I suppose you could use a sort of clockport style interface and have a service routine on the ARM do the grunt work of reading it then passing it off to or from the I/O devices.

That's what I was thinking.  The reason that is always given on why these retro systems cannot use USB is because the system (real retro) or the system they are recreating cannot handle the USB load, and don't have the USB software stack to handle it.

By doing all of the USB on the Arm, and just outputting in whatever format is the most convenient for the retro system, the ability of the retro system to handle a USB stack becomes irrelevant.  At the very least, it should be trivial to make a USB gamepad/USB keyboard/USB mouse to 9-pin joystick/PS/2 keyboard/PS/2 mouse adapter.  This would give all of the new retro systems the ability to use new periphrials.

Making data storage and network would be a little tougher, but shouldn't be over the top hard.