Potential add-on board?

[nyteschayde]

What will comnect to what? Cpu slot to usb2? maybe enough gpio to make a "software bus" but that wound not likely perform well. I made apb and ahb bus before on gpio, was very slow but suitable for the unusual situation at hand. Ibwouldnt do this for something in the real world.

It would need a card with a normal trap door edge connector. The CM3 has a slot based edge connector of its own. Hence it would need a card developed to interface and I am not presuming it would be easy.

[nyteschayde]

@nyteschayde: You're not the only one thinking about that idea: http://www.fpgaarcade.com/punbb/viewtopic.php?id=1221

Great minds think alike?

[Pat the Cat]

Not quite. It has a lot more IO pins on the edge connector, and these can be used as a local bus interface, similar to the original 68K.

That is what I thought until I checked the datasheet. The "extra" IO pins replicate the digital camera input on a trad Pi.

Nothing like the original 68K... although I guess maybe the Amiga video output could be routed to them. Very different voltage levels though.

Sorry? Me too.

EDIT: You do get some extra GPIO pins, but only 45 in total. Not enough to do to a full processor with on a pin to pin basis... but you are right in saying it does have extra pins.

Some potential, but not as much as you might think... Hmmm. Definitely something to mull over.

[EugeneNine]

It looks like ISA via USB is a possibility
https://www.raspberrypi.org/forums/viewtopic.php?t=46841

It looks though like one could bit bang out the GPIO to an ISA card so I'm thinking it should be possible for zorro slots too, espically with the 68k being async.  

I don't have any old cards to test with anymore.

[Pat the Cat]

Yes... ISA / PCMCIA / Zorro are roughly equivalent to the transmit/receive speed of a Pi.

One outlandish thought that crossed my mind would be hooking it up to an FPU socket, so that it mimics a standard 68882 but running at much higher speed.

20 Mflops? Sounds like quite a good idea to me, compared to most Amigas. :hammer:

[mikej]

EDIT: You do get some extra GPIO pins, but only 45 in total. Not enough to do to a full processor with on a pin to pin basis... but you are right in saying it does have extra pins.

Some potential, but not as much as you might think... Hmmm. Definitely something to mull over.

The GPIO pins are also connected to BCM ARM peripherals, for example i2c/spi etc.
SMI is one of these peripherals designed to connect to multiplexed address/data buses.
It can spit out some data at high speed, and a simple FPGA can then act as an interface to the 68K socket.

Dave has done some work here to replace a 6502
https://github.com/hoglet67/PiTubeDirect

My application, using the CM3 as a CPU in an FPGA system is quite a bit simpler as I have more flexibility in the interface timing.

I'll post more on the fpgaarcade.com forum as I make progress.

[kolla]

Sounds like a very clever idea. Any chance of blogging or documenting it?

Hm, yeah, I guess I could do that. Nag me again in a few weeks

I've been trying to setup a connection via a high speed PCMCIA serial port and not getting much success. Ideally I'd like to use the A1200 as programmer and archiver for the various bits of Pi and Arduino that I have.

I was not aware that there are high speed serial port PCMCIA cards that work with Amiga? I have a Silver Surfer that connects to the clock port myself, have not used it yet though... :p

GPIO pins are doable (just my opinion) but you have to be careful if power for the Pi goes that route - there is no protection for reversed polarity or 5V going down the wrong pin to a 3.3V input.

Yes indeed, voltage leveller is needed.

Maybe a dedicated HAT/pHAT specifically made to fit to Amiga parallel port (or even external floppy port - or both) could be a an interesting route to go

[bwldrbst]

I give all my Amiga systems a pi (zero), primarily to act as network bridge, giving them wifi (with modern capabilities)

Do you set this up as a PPP or SLIP via the serial port?

I am curious if it would be possible to network Amiga with Pi directly over parallel port, using the GPIO pins in the Pi. It is of course possible via Plipbox

This is an interesting idea. I think the Pi might be able to do it but the protocol would have to tolerate the non-real-time nature Linux running on the Pi.

OTOH, a parallel port connection to a Pi could expose a bunch of features - network, USB, storage - to an Amiga with the right device drivers:

Code: [Select]

[FONT=Courier New]                                           /-> Net Driver
RPi <--> GPIO <---> PAR Port <---> Amiga <---> USB Driver
Server                             Server  \-> Disk Driver[/FONT]


It'd be a lot of work and probably not very fast but a cheap way of adding features!

Cheers,

Andrew

[kolla]

Do you set this up as a PPP or SLIP via the serial port?

PPP via serial or ethernet via PCMCIA (or plipbox).

This is an interesting idea. I think the Pi might be able to do it but the protocol would have to tolerate the non-real-time nature Linux running on the Pi.[

OTOH, a parallel port connection to a Pi could expose a bunch of features - network, USB, storage - to an Amiga with the right device drivers:

Code: [Select]


[FONT=Courier New]                                           /-> Net Driver
RPi <--> GPIO <---> PAR Port <---> Amiga <---> USB Driver
Server                             Server  \-> Disk Driver[/FONT]


It'd be a lot of work and probably not very fast but a cheap way of adding features!

Cheers,

Andrew

My thoughts exactly

Another port that is typically not used much - external floppy port. I used to have AmigaLink which gave ethernet-alike network using the floppy port, and it was darn nice.

[Pat the Cat]

Hm, yeah, I guess I could do that. Nag me again in a few weeks ...

I was not aware that there are high speed serial port PCMCIA cards that work with Amiga? I have a Silver Surfer that connects to the clock port myself, have not used it yet though... :p

Two native types are Surf Squirrel/Whippet.

It struck me that PCMCIA serial ports from alien architectures have not been documented / investigated for years, so I thought that was a good area to explore and tinker with.

[nyteschayde]

I think just having a second CPU to delegate and run tasks on would be very nice indeed. Something we can compile to and connect with and run software on. If there was a native way, including the use of the edge connector of the CM3, to add the ARM CPU to the system, it could provide a very nice speed bump.

Or, if you're super crazy, an A1200 trapdoor connector that had slots for two CM3 cards. One to use as a second CPU (i.e. PPC in current classic Amigas) and another to use as a virtual 68K ala FPGA or as a separate set of peripherals to harness from for the Amiga (i.e. RAM, USB, WiFi, Bluetooth, GPU, etc...).

The cards are so small that they should easily fit at an angle like most SIMMs on todays  accelerators. They are also damn cheap.

[nyteschayde]

Also for throughput, the HDMI, networking and other medium I/O seem like they'd have to be high speed (relative to the Amiga) and could carry data back and forth if not used for their originally intended purposes.

[kolla]

Back in the days there was Siamese...
http://amiga.resource.cx/exp/siamese
http://www.nightvzn.net/portfolio/web/amiga_monitor/archives/1_11html/siamese.htm

This old idea is *much* more appealing today, using for example Raspberry Pi

[billt]

The Compute Module has the same form factor as a DDR2 SODIMM, so can be connected to Amiga buses.

What pins of that compute module will connect to what in the Amiga? There is not an exposed memory bus. There is a USB2, there is a number of GPIO, but nothing tha tI see as a good connection between them.

[billt]

The GPIO pins are also connected to BCM ARM peripherals, for example i2c/spi etc.
SMI is one of these peripherals designed to connect to multiplexed address/data buses.
It can spit out some data at high speed, and a simple FPGA can then act as an interface to the 68K socket.

I'll post more on the fpgaarcade.com forum as I make progress.

Ah, I had overlooked SMI before. 16bit data, OK for 68000 socket I guess. I only see 6 address bits though. Can likely use other GPIOs for irq inputs. Am I missing something, or is it that limited?

[nyteschayde]

I don't know if it is feasible, but it seems like video imagery could be used to transfer tons of data at high speeds. The imagery doesn't have to be sensibly viewable with the human eye, just be read and deconstructed for data. The covers data out from the CM3. The camera input could be a way to transmit data back to the CM3 from the Amiga. Again, I don't know if something like this is feasible, but it could be a potential hack.

Ultimately, I would imagine there might be a FPGA or other arbitrator on the physical board connecting the CM3 and the Amiga's edge connector. The FPGA/whatever could use more sane data transfer methods and bridge the physical pin disparity between the GPIO provided by the CM3 and the pins on the A1000/A500/A600/A1200 edge connectors.