Minimig PCB run - interest thread

[freqmax]

UAE hardfile support is plain verilog hacking :-)
Though the MCU would need some additional code to support write operations.
As for replacing the cpu, it's mainly a question about weather the number available fpga i/o's are enough.

[JimS]

freqmax wrote:
As for replacing the cpu, it's mainly a question about weather the number available fpga i/o's are enough.

I believe you'll also have to deal with the fact that other 68k family CPUs use 5v I/O while the FPGA uses 3.3V.

As to IDE support... has anyone considered SATA? It needs fewer pins.


BTW, I'm interested in an assembled board, if the ballpark cost mentioned earlier can be met. At my age, I can barely see those 0.5mm pins, let alone solder them. ;-)

[maffoo]

JimS wrote:

I believe you'll also have to deal with the fact that other 68k family CPUs use 5v I/O while the FPGA uses 3.3V.

Does this mean that 68010 isn't an option? I know things get more complicated with later 68k CPUs but IIRC the 68010 could be used as a drop-in replacement for the 68000 in A500s. If it is possible to use a 68010, would there be any disadvantage? I'm wondering if there would be any value in having the CPU socketed so users could choose between the two CPUs.

As to IDE support... has anyone considered SATA? It needs fewer pins.

I had wondered about SATA, but I thought it might be too complex at this stage.

What I would like to see is USB for keyboard, mouse and joystick, and SATA for storage (although HDF support would be enough for me.) The reason being that PS/2 and IDE are becoming obsolete, it makes more sense to me to make it compatible with the most up-to-date technology.

Matthew

[freqmax]

The datasheet for MC68040 I looked at says Vcc 0V-7V. So I guess 3.3V operation is ok. S-ATA is nice but requires either an transceiver/PHY => more pins. Or an FPGA with S-ATA port => Virtex-4 FX => Significantly more cost & use of bga packages.

[JimS]

freqmax wrote:
The datasheet for MC68040 I looked at says Vcc 0V-7V. So I guess 3.3V operation is ok. S-ATA is nice but requires either an transceiver/PHY => more pins. Or an FPGA with S-ATA port => Virtex-4 FX => Significantly more cost & use of bga packages.

Ahh.... it's always something. ;-) I'd *guess* that if you ran a 68040 at 3.3V, you'd need to roll down the clock speed to get reliable operation. But that's just a guess on my part. I seem to recall Dennis saying he picked this particular CPU because it was 3.3V and compatible with the FPGA. Be great if faster CPUs were an option.... either with an actual CPU, or another FPGA running a 68K core.

The folks at Schmartboard have announced BGA versions of their prototype boards. Last time I looked it wasn't shipping yet...

For the USB interface, how about the Vinculum chip? It has it's own CPU that runs a USB host stack. Interface is via either a UART, SPI or FIFO. I believe there's a spare SPI on the Minimig...

[ShawnDude]

But would all of those pins necessarily need to be connected to the FPGA.  Or could the FPGA be made to have the data lines, minimum address lines, minimum control lines.  Since the additional address lines would be for extra memory therefore not need to go to the FPGA and the control lines would not need to go there also. Maybe set the MiniMig up the it has a header which connects to a CPU/Memory/Additional (IDE, ZORRO, etc).  Just use the MiniMig core as the custom chipset replacement (sound, graphics, I/O).  The MiniMig should still have the onboard memory but be used as ChipRAM and Kickstart. All other FastRAM would be with the CPU. Just a thought. Wouldn't be much different than some other Amiga upgrades (jumper wires everywhere)

[ivier]

JimS wrote:
For the USB interface, how about the Vinculum chip? It has it's own CPU that runs a USB host stack. Interface is via either a UART, SPI or FIFO. I believe there's a spare SPI on the Minimig...

That chip looks quite useful. From my scan thru of the data sheet, it could allow access to USB mass storage devices, USB mice and keyboards, and perhaps more. All with only 4 pins to interface it (in SPI mode).

The one thing that gets me though, is it claims USB 2.0, but is only capable of 12Mb/s. That makes it USB 1.1 not 2.0, not that it matters much since the CPU can't handle USB 2.0.

[freqmax]

ivier:
I think it's possible to get usb by simple using two pins on the fpga, albeit maybe only usb1.1 at 12Mbps. For usb2.0 at 480 MBps it may need a PHY chip.
But any cpu to shuffle data will likely slow things down a lot.

Seeing a lot of suggestions for Minimig. I think actually USB makes most sense. As one can get keyboard, mouse, joystick, mass storage, rs232, soundcard, ethernet (netboot!), etc.. from ONE usb port via an hub.

As for USB2 it's a real FAKE, your equipment can be USB2 complaint but unable to perform 480 Mbps operation!

JimS:
Actually to enable higher speed, voltage is lowered. This is related to flank times and P=U²/R ie the energy dumped during switching.

[FrenchShark]

freqmax wrote:
The datasheet for MC68040 I looked at says Vcc 0V-7V. So I guess 3.3V operation is ok.

There is a specific 3.3V version of the 68040 it is called 68040V.
If you want to save some pins on your FPGA, you can design the board like on a real Amiga : the Chip-RAM bus and the Fast-RAM bus are separated by buffers. Agnus takes care of the Output Enable of these buffers.

[jkonstan]

A USB Host Controller usually connects back to a host processor on a high bandwidth bus (parallel CPU bus, PCI, clock port, etc ..) in order to be able have high bandwidth transfers. The Vinculum parallel FIFO interface mode with 8 bit bi-directional data bus and simple 4 wire handshake for data I/O and command monitor interface would work well interfaced back to the Xilinx FPGA or to the 68K bus. The issue with USB host on the present Minimig PCB would be the speed of a serial SPI connection from 68K/Xilinx_FPGA to a Vinculum USB HOST controller that would most likely limit the bandwidth/transfer rate. Data sheet has Vinculum SPI port max SPI Clock = 10Mhz => 10Mbits/sec Max SPI transfer rate; thus, a Vinculum SPI connection in any application will have a limit on the SPI tranfer rate of 10Mbits/sec or maybe lower due to possible signal integrity issues on a 2layer PCB.

Also, USB 2.0 compliant device does not have to support USB 2.0 High speed (480Mbits/sec) transfer mode. A USB 2.0 compliant device such as Vinculum only have to support "Basic-Speed" of 1.5Mbits/sec (Low speed) & 12Mbits/sec (Full Speed) while ignoring the high speed handshake from a USB 2.0 High speed (480Mbits/sec) device so that the High Speed device (480Mbits/sec) will kick back down to the old 12Mbits/sec (Full Speed) speed mode.

  :-)

[mongo]

JimS wrote:

As to IDE support... has anyone considered SATA? It needs fewer pins.

The FPGA in the MiniMig currently has 4 unused I/O pins. That's more than enough to add IDE.

[rkauer]

Count me in for original (1.0 or 1.1, wathever) 12x12 kit (not assembled, only the board and parts). :cheers:

[Crom00]

http://www.fujiyama.cn/Company.asp

Found the above factory in Shenzen China.

They sell some curious products.

Most intersting is a nifty gadget... Get this, a classic Nintendo 16,8bit,gameboy emulator,AVI,WMV,ebook,picture viewer & camera features, 1 gig ram, sd card slot, FM radio, usb2 with a TVT monitor, and TV output.

It's intersting to note they also offer industrial services with payment terms clearly listed.

Seems if larger numbers with a complete system are ever considered an outfit like this can do the job. From my expereince factories like this have cheap labor and technical expertise to pull off some of the things the community is looking to do like usb, faster CPU, more ports.

[Fester]

Has anyone tabulated the list of interested people? Are we going to get some kind of email if this run actually happens?

[yssing]

Well, the authors of this thread could set up an "official" poll, about how many you would like to get, and then sign with an e-mail addy.

[CD32Freak]

I'm surprised that after more than 2 weeks since Dennis released the Minimig sources, no one has even produced a bare Minimig board. So what's your excuse? Amiga fatigue? :lol: