[Coco] CoCo3FPGA, FPGA Development, and GIME replacement

[John Kent]

On 6/07/2011 3:01 AM, John Kent wrote:
> Hi Joel,
>
>>
>> This is the only thing I have bookmarked:  
>> http://www.xilinx.com/support/download/index.htm
>>
>> Now, I only downloaded the 900M one instead of the 4G one where they 
>> have high resolution JPEGs and a Bio of each logic gate.  When I 
>> originally set up my CoCo3FPGA system I tried an earlier version of 
>> Webpack on Win2K.  I finally figured out how to get that to work just 
>> to upload the bit file.  That machine has suffered a hardware 
>> failure, and I'm just not using MS-Windows enough these days (other 
>> than fixing other people's malware-infested boxes) to bother 
>> reconstituting it.  Gary's got a new version with pretty 4096-color 
>> graphics, so I downloaded the Linux version (I'm running Ubuntu 10.04 
>> on this machine) for the upgrade.  Unfortunately, the Digilent board 
>> requires hardware modification for the new colors, and that simply 
>> hasn't gotten done yet.
>>
>> Like John K. says, you've got to register with them and do a deal 
>> with Rumplestiltskin for your firstborn child, but no money changes 
>> hands, and they haven't come to collect Henry yet.
>>
>> JCE
>>
>
> One thing worth explaining is that so far Gary has only made the 
> binary or bit file of CoCo3FPGA available, so all you are doing with 
> the development software is using the programmer section to download 
> the binary to the FPGA or configuration Flash memory. I do have an old 
> copy of Gary's verilog code that he gave me ages ago but things have 
> changed a fair bit since then. I think he does plan to release the 
> source code when he gets it to a point where he is ready to distribute 
> it.
>
> My system09 project is a system on a chip that is similar to the old 
> South West Technical Product Computer 6809. It does have a color 
> display although it does not have the same resolution graphics as on 
> theCoCo.  Most of the software for the SWTPc was text based. It has 
> PS/2 keyboard, RS232 port and extended memory. System09 does however 
> fit in a 200Kgate FPGA boards, so it's much smaller than Gary's 
> CoCo3FPGA.
>
> I've ported system09 to a variety of FPGA boards, some of which have a 
> 16 bit IDE port which I have connected up to a Compact Flash card 
> running in True IDE mode. I'm running the old Flex 9 software and I've 
> written IDE drivers for it that allow me to interface an IDE hard disk 
> or CF card.
>
> It should be possible to add an IDE port on the end connector of the 
> Digilent Spartan 3 starter board. Alex Freed cut and jumpered the 
> tracks of a Digilent test point header board to rewire the Spartan 3 
> starter board to a 40 pin IDE socket for his Apple II implementation. 
> It's then possible to use a commercial IDE to CF card adapter to 
> interface to a CF card. Digilent however no longer sell the test point 
> header board, so you'd need some other way to transpose the pins. I 
> haven't bothered to do it with my system09 because I can't find an 
> elegant way to do it.

And I'm lazy

>
> The CF card operates at 3.3V. If you hooked up a Hard Disk drive 
> running at 5v you'd need series 100ohm protection resistors in the 
> signal lines.
>
> The point is that it wouldn't be hard to implement an IDE interface on 
> the Spartan 3 starter board and that would give you stand alone 
> operation. There are 32 uncommitted pins on the end connector of the 
> Spartan 3 starter board which are more than sufficient for a 16 bit 
> data bus, 3 address lines, 2 chip selects and 2 read/write signals.
>
> The DE1 board has an SD card socket on it however implementing an SD 
> card interface from the little information I have seen is much harder 
> than writing and IDE driver. The IDE driver simply has to set up the 
> sector cylinder and head registers issue a read or write command to 
> the command register and poll a couple of status bits to see when data 
> is ready on the data bus. The issue then is how to interface it to 
> disk BASIC.
>
> Anyway I am rabbiting on ... 3.00am here in Melbourne Australia. Time 
> for bed.
>
> John.
>

-- 
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