[Coco] Coco compatible monitors...

[Joel Ewy]

On 07/05/2011 10:29 AM, gene heskett wrote:
> On Tuesday, July 05, 2011 11:23:07 AM John Kent did opine:
>
>> Hi Gene
>>
>> On 6/07/2011 12:04 AM, gene heskett wrote:
>>> On Tuesday, July 05, 2011 09:50:20 AM John Kent did opine:
>>>> Terasic DE1 is here:
>>>> http://www.terasic.com.tw/cgi-bin/page/archive.pl?No=83
>>> No doubt capable, but way too big to hide in a cc3 unless the whole
>>> coco was emulated.
>> You've seen Gary's CoCo3FPGA, surely .... It's been mentioned on the
>> list often enough.
>> It emulates the entire CoCo3 and uses a modern LCD display and PS/2
>> keyboard.
>>
>> You'd have to design your own PCB for the GIME chip replacement.
>> The point was that with the CoCo3 design there should be a GIME
>> component to the design that could be separated off an put into it's own
>> smaller FPGA. That is if Gary makes his CoCo3FPGA open source, which I
>> think he plans to in the not to distant future.
>>
> That, or a reasonable fee, will be the make or break for me.  I have a
> couple coco3's I can salvage a case from, one of which is Dennis Scala's
> original machine, with a very noisy gime in it.
>
> That keyboard in Joel's conversion sure looks nice, I wonder where did it
> come from?
>

I don't remember where it got it, but geeks.com is a likely candidate.  
Looking over their keyboard selection at the moment, they don't appear 
to have any PS/2 mini keyboards.  They do have USB mini keyboards, which 
won't work on CoCo3FPGA.  Those are nice for the workbench where I've 
got a bunch of computers hooked up, and space is at a premium.  The one 
I used in the CoCo3FPGA had a built-in serial touchpad, which has now 
been liberated for other potential uses.  But you never know when they 
might get more similar keyboards in.

JCE

>>> That maybe could be hidden under the keyboard.  With a vga output no
>>> less.
>>>
>>> Would I have to run the development system on windows?  If yes, no
>>> deal.
>> The Spartan 3 starter board does have expansion connectors, but whether
>> there are enough pins for the PLCC 68 pin chip I'm not sure. Some of the
>> pins on some of the connectors are shared with the on board SRAM address
>> and data bus, but if you disabled the on board RAM you could use them.
>>
>> You'd still need the 3.3V to 5V bus switches to do the level conversion.
>>
>>> the development stuff for xilinx is nearly free, so that, and custom
>>> made breakout cables might add a lot of functionality to a coco3.
>> Xilinx have webpack ISE which is free to download. It's about 2-3GB.
>> Altera have free Quartus II development software which is a similar
>> size. You'd have to register with Xilinx or Altera to download them.
> ah, that explains why the stuff I grabbed was just a few megabytes.
>
>> You'd have to learn verilog or VHDL hardware description languages,
>> although there might be a schematic capture option too, although that is
>> not portable between the two vendors I don't think. VHDL&  verilog are
>> similar to normal pogramming languages in that they have standard
>> control structures such as case/when and if/then/else. The difference is
>> that you are generating a hardware description with them rather than a
>> set of instructions. Case/when for instance is analogous to a decoder
>> chip, or multiplexer, although the inputs and outputs are not restricted
>> to a single bit.
>>
>> Micro computers are essentially time division multiplexed logic using
>> the ALU to perform the operations sequentially. With a hardware
>> description language like verilog or VHDL you are actually defining a
>> hardware configuration for the FPGA logic that operates in parallel with
>> all the other hardware.  It's a like connecting all the ALU operations
>> of a micro computer end to end to operate in parallel with the variables
>> being hardware registers in between the various stages.
>>
>> VHDL and Verilog allow you to define components or entities that can be
>> instantiated as many times as you like, or as many times as fits in the
>> chip. So for instance if you define a 6850 ACIA you can instantiate it
>> (i.e. produces copies of it from the definition) as many times as you
>> like in your design. You are of course limited by the amount of logic
>> available in the FPGA and you have to connect them together in your
>> design.
> Well, if the water doesn't get too high...
>
>>> For about 90 bucks and some time, that looks like a usable gizmo.
>>> IIRC,
>> There are only 40 pins available on the XuLA boards and a number of them
>> are allocated to supply rails, clocks and resets and so on. Some of the
>> pins are inputs only and again you'd need 3.3V to 5V bus switches.
>>
>>>> There are a number of other Xilinx boards from Digilent Inc. and
>>>> others.
>>>>
>>>> Digilent is to Xilinx what Terasic is to Altera.
>>>>
>>>> There are pictures of the FPGA boards I use on my FPGA page:
>>>> http://members.optusnet.com.au/jekent/FPGA.htm
>>> bookmarked.
>>> Cheers, gene
>> Hope that helps explain things.
> Considerably, thanks John.
>
>
> Cheers, gene