Question about USB on the minimig

[little]

Coldfire would be cool for a next generation projet, they have released v5 that runs at a nice 400mhz, add some PowerVR SGX for the graphics and you have some pretty competent hardware.

But for a project with emphasis in running 16-bit software it is not the right solution since it is not 100% compatible with the 68000.

[little]

So, my question is, given that we have already established that the processor speed is not an issue due to solutions with there own built in processor, what prevents USB from working from Workbench?

Hear, hear!

If people really want to use their USB joysticks with 16bit era machines then the solution is to make an usb to de-9, this could also of interest users of msx, commodore 64, sega genesis, etc. You can already connect some USB keyboards to the ps/2 interface with an included adaptor.

I think the best use for an USB interface is to connect cd-roms and there will be people interested in scanners, external hard disks, etc.

As a side query, does anybody know if the PIC controller could be used for the USB interface or if using a more powerful/bigger PIC would allow such functionality? This would have the side benefit of allowing transparent use by games of USB joysticks :-p an also would keep the cost and simplicity of the design.

[little]

The whole point is that (OS transparent USB) is really difficult, requires a lot of extra hardware and why not just use PS2 keyboards, mice and 9-pin joysticks?

As I have said before, I think an USB to DE-9 adapter for joystick and mice would suffice, but there is another reason for an OS transparent USB interface. It would enable transparent emulation of the CDTV/A570 and later on it would be posible to create verilog code to run other CD-ROM/68000 based hardware. This will be beyond the capacities of minimig 1, but I think we all agree USB 1.1 is all about minimig 2.0 :-)

[little]

an USB to de-9 adapter would suffice (provided it can also work with Mice)

I think that since mice are quite simple (2-5 buttons/0-1 rudder wheel) would make more sense to make a ps/2 to de-9 adapter just for mice? I am quite surprised that no one has made such an adapter already, since most amiga mice must be quite worn out by now and such adapter would be quite cheap to produce.

[little]

Modern PC's have several advantages, CPU Speed (Raw grunt), as well as DMA Channels, which means CPU doesn't get bogged down.

But the amiga has a bus architecture and utilizes direct memory access (DMA) technique. If I undestand correctly it should be feasible to do a USB interface that used DMA to fetch the data.

As I side note that no one has mentioned, another advantage of USB is that you can add a WiFi interface to the amiga thru a USB port (it would require an amiga driver, but anything network related is done thru the workbench anyway).

[little]

this is a perfect example of why USB would be good.

As a side note, doing some web-surfing I found out that the PIC18F2550, PIC18F2553 and PIC18F2580 have built in USB 2.0 ports, so there is no need of a complete redesing of the minimig to add USB, just replace the PIC18LF252-I/SP with one of his three "big brothers" and write the required code.

[little]

The only limitation of ANAIIS is the lack of isochronous support (can't use audio, video,...) but a simple 68000 can't manage interrupt each millisecond,

Very interesting. Do you think that if the 68000 is overclocked to 28mhz (instead of the stock 7 Mhz) it would be feasible to support isochronous mode?

This chip seems pretty marvelous, more info here and here. IMHO is this is added to minimig 2.0 it would allow cd/dvd drives, hard drives, memory sticks, mouse, keyboard, printers, wifi connections, network connections, joysticks and maybe floppy drives (I have no idea if it is feasible to read amiga formatted and copy protected disks), albeit I have no idea if the PIC has enough memory to control the uhc124 and many drivers for amigaos would need to be written.

edit: The uhc124 is only $4.80 retail O_o;

[little]

I was toying with the idea whether it would make sense to put an ARM processor with USB master capability on the board.

Would it be expensive?