We need volunteers to design various part of the hardware. Below is a list
of tasks that need doing.
Most correspondence should be directed at the mailing list:
riscy@pyramid.com
Anything is open for discussion including the choice of CPU.
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* CPU, peripheral controller and memory
Allocated to: caret@pyramid.com
There is no problem getting CPUs. The memory design is a function
of what memory controller is available. At this stage I am aiming
at using the IDT 79R3730. To this end I am calling IDT to attempt
to get advance information and samples. When I get better information,
most other developers will get the data sheet from me to allow design
of their respective interfaces to this chip.
* Keyboard controller / NV-RAM / RTC
Allocated to: <no-one>
Research needs to be done on what is available, its cost and
then the design of the appropriate circuit. These devices would
be connected to the 8-bit bus of the 3730; they would be selected
with a chip-select and possible several address bits.
* ISA bus
Allocated to: <no-one>
This one is hard. An interface from probably the B bus of the
3730 to the ISA backplane needs to be researched and designed.
I figure that an ASIC for doing this such as found on any
motherboard these days, along with the associated interface
logic to convert R3000 control signals to x86 signals would
be more complicated and more expensive than doing the whole
thing in discrete logic. Silicon Graphics Inc have information
available on how to do this though and should be contacted.
* SCSI bus
Allocated to: <no-one>
The SCSI bus would probably be done with something like a
NEC 53C94 SCSI controller. Research needs to be done on this
and other available SCSI chips.
* Serial port
Allocated to: <no-one>
Some sort of serial ports should be investigated to be connected
to the A bus of the 3730. NS16550's would be appropriate
but other ideas might be looked into.
* Ethernet port
Allocated to: <no-one>
It has been suggested that we use an Am7990 (Lance) Ethernet
controller. I know nothing about this chip. I expect that it
could be connected to the 8-bit or 8/16-bit bus of the 3730.
* Video
Allocated to: <no-one>
The IDT 79R3730 handles the DMA of rasters from DRAM and the
serialization into 1, 2 or 4 bits per pixel. This could be
buffered to form 8-bits per pixel then fed into a suitable
colour palette. Then all that remains is to generate the
pixel clock and the appropriate sync signals. The sync stuff
could come from a motorola 6845 or the like. Because of the
3730, this section should be real cheap. If it doesn't turn out
that way, then we should abandon this for some video controller
on the ISA bus. Resolutions up to 1280x1024x256 should be
supported.
* Diagnostics / monitor code
Allocated to: caret@pyramid.com and <someone else>
Some initial code needs to be written to test the board and
load the operating system.
* Cross assembler/compiler system
Allocated to: <no-one>
Someone needs to compile GCC/GAS/GLD on a x86 system to cross
compile code for the R3000.
* Organize the schematics from the various designers.
Allocate to: caret@pyramid.com
This one is an interesting one. What we need is a free CAD
system to do schematic capture. Someone what to write one
by next week? :-) My alternative suggestion is to use something
like xfig or even to hand write them and send them to me.
Alternatively, I use Protel; if anyone has that, then just
send the schematic files.
* Printed Circuit Board design
Allocated to: <no-one>
I will be happy to design the board. As I mentioned above,
I use Protel. If someone has better, then are certainly welcome
to design the board.
--
Neil Russell (The wizard from OZ)
Pyramid Technology Email: caret@pyramid.com
3860 N. First Street Voice: (408) 428-7302
San Jose, CA 95134-1702 FAX: (408) 428-8845
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