stephen_usher wrote:Peter wrote:If someone does it anyway, I propose PS/2 as standard. It is well documented, long established, and implemented on superHermes and Q68. It could also be of general use beyond the QL.
It's also obsolete and has been for 20 years. Getting new PS/2 peripherals is problematic at best.
In this context I meant PS/2 for interfacing your hypothetical Raspi USB "coprocessor" to QL/Q68-style hardware, not to connect peripherals. But it could also be SPI or I2C - that's a relatively minor issue, and I lack the time to explain in more detail.
stephen_usher wrote:And again, you're concentrating purely on the keyboard (and maybe mouse) and not the plethora of other devices, such as printers, networking, storage etc.
Of course I'd concentrate on USB HID first, if I worked on USB via Raspi/ARM (I don't !). Because if that amount of work is already too high, it is pointless to raise complexity even more.
stephen_usher wrote:Would waiting a couple of seconds for a stripped down Pi boot be so much of a problem? Remember it wouldn't be a full system, merely a kernel and the minimal number of processes required to handle the USB and interface to the QL side of things.
Please feel free to actually set up such a system and start implementing QL support for your above mentioned devices. The more you look into the details, the more you will understand the issues. I don't want to go into a full "USB for the QL" discussion here.
stephen_usher wrote:No shells, no other daemons, no systemd, read-only filesystem.i.e. an embedded system device controller, as per the set-up for the ZX Spectrum Next.
So the Spectrum Next has USB mouse, printers, networking and storage support via Raspi this way? Can you provide a link?