[Coco] FPGA CoCos

Dave Philipsen dave at davebiz.com
Fri May 22 21:55:41 EDT 2015


Ok. Well, it's just a little fuzzy to me.  The BASIC he is using is 
definitely the same BASIC that was used in the CoCo which to my 
knowledge was created by Microsoft.  I know this because you can follow 
right along with the BASIC unraveled book which disassembles the CoCo 
ROM.  As long as Grant knows it's ok to use that's fine with me but I 
may be a little hesitant about passing it along to anyone else since I 
don't personally know what the agreement is.  It doesn't matter that 
much as the project could be made so that each person would have to 
obtain their own ROM image.  And, as far as I can tell, there are plenty 
of them floating around on the internet if you don't have the ability to 
personally dump the ROM from your CoCo.

I believe the AS9 assembler came from Motorola has always been free.  I 
personally prefer the CSC6809 assembler.  It was created a number of 
years ago by a guy named Bud Pass of Computer Systems Consultants in 
Georgia.  I bought the source code from him (in C) for the 6502, 6809, 
6801, 8048, and 8051 processors.  Included in the package was the source 
code for some utilities that are used to convert files to different 
formats for development purposes so I can convert between binary, 
Motorola S records, Intel hex files, etc. along with some disassemblers. 
   I think I purchased the whole package for $200 back in 1990. I bought 
it primarily because I needed to modify the 6502 assembler to support 
some new opcodes in the Rockwell 65C02 which I and a company I was 
working with at the time needed for some show control applications in 
various theme park applications around the world.  The company preferred 
the 65C02 over the 6809 because it was available in 4MHz speeds and the 
6809 could only do 2MHz and I think the Hitachi 63C09 would max at 3 
MHz.  We later did some projects with the 68HC11 which is basically an 
offshoot of the 6801.  Some versions were available with a 4MHz internal 
clock.  It's got some similarities to the 6809 but it can't do position 
independent code.

At any rate this FPGA stuff takes things to a whole new level. There are 
some things which just don't require the complexity of a 16 or 32-bit 
CPU for embedded applications but the 6809 was a black sheep and 
Motorola evidently just completely dumped it in favor of pursuing the 
680x0.  Well, IMHO they should have continued to improve the 6809 by at 
least making it available in higher speeds. Today, the FPGA does all of 
that for us.

Dave


On 5/22/2015 4:25 PM, Bill Nobel wrote:
> AFAIK Dave the code for Microsoft Basic Grant has releases as freeware.  I have another copy of his Basic for the SBC he released and Kip has gotten permission from Grant to use it in his project for the Kipper Bus.  Grant does state that it can only be used for non-commercial purposes.  He has also released the AS9 assembler from his site to compile it on a PC as well.
>
> Bill Nobel
>
>> On May 22, 2015, at 2:45 PM, Dave Philipsen <dave at davebiz.com> wrote:
>>
>> Sure, I can release the source.  It needs to be cleaned up a bit first and I'm not real sure about the MS Basic that Grant packaged with it.  I'm sure it must be copyrighted and I don't want to get in trouble for posting it somewhere.  It's nice....the source code with comments comes from the BASIC unraveled series.  He just pulled out the code for sound, cassette, graphics, joysticks, etc.  I'll try to get it ready soon but remind me again if you don't hear from me about it soon.  If nothing else I can just zip it and send it to you directly via email.
>>
>> Dave
>>
>>
>> On 5/22/2015 8:19 AM, Gustavo Ranaur Schoenaker wrote:
>>> Excelent Dave. I have also a DE1, that won´t probably work with CoCoFPGA.
>>> (That´s why I left it after taking over the world. :-))
>>>
>>> Can you release the source? That's a good project to work on!
>>>
>>> Regards,
>>>
>>> On Fri, May 22, 2015 at 4:39 AM, Dave Philipsen <dave at davebiz.com> wrote:
>>>
>>>> On 5/21/2015 9:30 PM, Mark McDougall wrote:
>>>>
>>>>> On 22/05/2015 11:10 AM, Dave Philipsen wrote:
>>>>>
>>>>>   Well, that's good to know. It's a shame that Altera changed the memory
>>>>>> and
>>>>>> couldn't find a chip that is at least compatible with the old one.
>>>>>>
>>>>> FTR the board is produced by TerASIC, not Altera.
>>>>>
>>>> True.  That's what I should have said.
>>>>
>>>>>   Unfortunately, Gary doesn't publish the source and I'm not sure he has
>>>>>> time
>>>>>> to keep up with it (although I don't know him personally nor have I
>>>>>> communicated with him).
>>>>>>
>>>>> He did publish some early source, though I don't recall if that was for
>>>>> the DE1 or not. I ported an early version of his Xilinx-based project to
>>>>> the DE1 (older board) but that's very outdated now.
>>>>>
>>>>>   Anyway, it will be handy for other things IF I can get this stinkin SRAM
>>>>>> figured out.  It doesn't behave like most standard SRAMs and I frankly
>>>>>> don't
>>>>>> have that much experience with VHDL to figure it out.
>>>>>>
>>>>> Yeah I'm not really sure what the issue is as I have an older board.
>>>>>
>>>> After about 3 hours of trial and error this amateur VHDL coder got it
>>>> figured out! (I'm sure a more experienced person would have figured it out
>>>> in no time)  A few very minor changes to Grant Searle's project  (which was
>>>> written for a pretty standard 128K x 8 SRAM) makes it work on the new DE1
>>>> board.  The 256K x 16 SRAM on the DE1 now looks like 512K x 8 to the
>>>> Multicomp project and my MMU which works on another board with a 512K x 8
>>>> RAM now works on the DE1.
>>>>
>>>> Next issue to tackle: make a file system to access the SD Card in FAT 16
>>>> and eventually FAT32 formats.
>>>>
>>>>
>>>>> Regards,
>>>>>
>>>>>
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>>>>
>>
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