[Coco] FPGA 6809

Dave Philipsen dave at davebiz.com
Mon Aug 31 12:58:27 EDT 2015


FWIW, I am playing around with a little tiny WiFi card that I bought 
from China.  It TCP/IP over wifi via RS232.  I set up one board on a PC 
and talked to it using hyperterminal and the other board on my DE1 with 
the MultiComp project installed and a quick and dirty terminal program 
and I was able to communicate between the two over my wifi network.  I 
also tested making some http GET requests and was able to pull down some 
webpages from the internet.  The really cool thing is that the card only 
costs about 2 bucks.

Dave Philipsen


On , Bill Nobel wrote:
> I definitely agree with the Nitros9 part, as I am part of the
> creators.  I am so looking forward to SD card and possible TCP/IP via
> RS-232 (beyond DriveWire).
> 
> Bill Nobel
> 
>> On Aug 30, 2015, at 11:41 PM, Dave Philipsen <dave at davebiz.com> wrote:
>> 
>> I have not yet seen Roger's project.  Does he have a website?  I 
>> definitely like what Gary has done on the DE1.  To me there is nothing 
>> like having a standalone little 6809 computer that can run NitrOS9 at 
>> 25 MHz!  Gary just released a new version with support for SD cards 
>> and I'm working on getting it to boot OS9 from the SD card with some 
>> software that will allow me to create partitions on the SD card.  
>> Drivewire is a nice concept but for some reason I just can't warm up 
>> to the idea of having to have a PC running next to my OS9 computer.  
>> It's great for printing or accessing the internet I guess but I really 
>> like the fact that we're getting really close to having a relatively 
>> fast little computer that boots NitrOS9 on its own, requires very 
>> little power, and has plenty of on-board storage capability.
>> 
>> Dave Philipsen
>> 
>> 
>> On 8/31/2015 12:19 AM, Bill Nobel wrote:
>>> That is correct.  I would like to achieve various 6809 systems (the 
>>> main being a Coco).  Yes Roger & Gary Becker have their projects 
>>> going (I prefer Gary’s better) I tried taking Grant’s code direct to 
>>> De0 with pin re-assingment. This didn’t work under newest versions of 
>>> Quartus, so I have been trying to fix the varieties for my own 
>>> sentiment.  Once I have them working Everyone gets.
>>> 
>>> Bill Nobel
>>> 
>>>> On Aug 30, 2015, at 10:58 PM, Dave Philipsen <dave at davebiz.com> 
>>>> wrote:
>>>> 
>>>> Interesting.  So when you are speaking in terms of "bdf" does that 
>>>> mean you are actually drawing a schematic for your implementation?
>>>> 
>>>> Dave
>>>> 
>>>> 
>>>> On 8/30/2015 11:52 PM, Bill Nobel wrote:
>>>>> Exactly what I am talking about David.  Grant defines his CS lines 
>>>>> in code vs .bdf (or symbols) My knowledge of FPGA’s is in schematic 
>>>>> form.
>>>>> 
>>>>> Bill Nobel
>>>>> 
>>>>>> On Aug 30, 2015, at 10:46 PM, Dave Philipsen <dave at davebiz.com> 
>>>>>> wrote:
>>>>>> 
>>>>>> Actually, I stand corrected.  Grant doesn't actually "marry" the 
>>>>>> buses in his project and he explains why on his website:
>>>>>> 
>>>>>> Similarly, all these CPUs have an 8-bit data bus. For the discrete 
>>>>>> components, the data bus is bidirectional. This could have been 
>>>>>> implemented in VHDL as bidirectional to match. However, the VHDL 
>>>>>> components (including RAM and ROM) tend to have separate incoming 
>>>>>> and outgoing data buses - this makes it easier to interface. 
>>>>>> Therefore the 8-bit data bus found on a CPU is represented as two 
>>>>>> separate data buses and are connected to the two data buses on the 
>>>>>> breadboard.
>>>>>> 
>>>>>> eg
>>>>>> di => cpuDataIn,
>>>>>> do => cpuDataOut
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> This code in Multicomp attaches the different peripherals to the 
>>>>>> CPU read data bus when the respective chip select goes low:
>>>>>> 
>>>>>> cpuDataIn <=
>>>>>> interface1DataOut when n_interface1CS = '0' else
>>>>>> interface2DataOut when n_interface2CS = '0' else
>>>>>> sdCardDataOut when n_sdCardCS = '0' else
>>>>>> basRomData when n_basRomCS = '0' else
>>>>>> internalRam1DataOut when n_internalRam1CS= '0' else
>>>>>> sramData when n_externalRamCS= '0' else
>>>>>> x"FF";
>>>>>> 
>>>>>> 
>>>>>> An example of connecting the CPU write data bus to an external RAM 
>>>>>> chip is found here:
>>>>>> 
>>>>>> sramAddress(15 downto 0) <= cpuAddress(15 downto 0);
>>>>>> sramData <= cpuDataOut when n_WR='0' else (others => 'Z');
>>>>>> n_sRamWE <= n_memWR;
>>>>>> n_sRamOE <= n_memRD;
>>>>>> n_sRamCS <= n_externalRamCS;
>>>>>> 
>>>>>> This is the way he keeps it flexible in order to work with both 
>>>>>> the "internal" VHDL devices which may use separate data buses as 
>>>>>> well as the real external devices that normally use a single 
>>>>>> bi-directional bus.  Additionally, there are some physical devices 
>>>>>> which do not require the chip select to be active in order to 
>>>>>> perform a write operation.
>>>>>> 
>>>>>> Dave Philipsen
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> On 8/30/2015 10:42 PM, Bill Nobel wrote:
>>>>>>> I have gone over Grants code extensively and I never found a 
>>>>>>> symbol file for Chip select. I see the CS lines defined, but not 
>>>>>>> such as Roger’s define for a symbol file.
>>>>>>> 
>>>>>>> Bill Nobel
>>>>>>> 
>>>>>>>> On Aug 30, 2015, at 9:23 PM, Dave Philipsen <dave at davebiz.com> 
>>>>>>>> wrote:
>>>>>>>> 
>>>>>>>> If you take a look at the VHDL code in Grant Searle's Multicomp 
>>>>>>>> project you'll find an example of this too.
>>>>>>>> 
>>>>>>>> Dave Philipsen
>>>>>>>> 
>>>>>>>> 
>>>>>>>> On 8/30/2015 8:53 PM, Bill Nobel wrote:
>>>>>>>>> I have to post this here,  A HUGE shout out to Roger Taylor for 
>>>>>>>>> directing me in the right direction for the bus marriage on the 
>>>>>>>>> FPGA versions of the 6809.  I am a noob when it comes to these 
>>>>>>>>> things and was having trouble marrying the data_in data_out 
>>>>>>>>> busses together to form a actual bi-directional bus.  I thought 
>>>>>>>>> I was needing to build a circuit with latches/buffers, and he 
>>>>>>>>> decides to give me a ~20 line piece of vhdl code that does the 
>>>>>>>>> whole works based on Chip selects. Woo hoo….
>>>>>>>>> 
>>>>>>>>> Bill Nobel
>>>>>>>>> 
>>>>>>>>> 
>>>>>>>> ---
>>>>>>>> This email has been checked for viruses by Avast antivirus 
>>>>>>>> software.
>>>>>>>> https://www.avast.com/antivirus
>>>>>>>> 
>>>>>>>> 
>>>>>>>> --
>>>>>>>> Coco mailing list
>>>>>>>> Coco at maltedmedia.com
>>>>>>>> https://pairlist5.pair.net/mailman/listinfo/coco
>>>>>> 
>>>>>> ---
>>>>>> This email has been checked for viruses by Avast antivirus 
>>>>>> software.
>>>>>> https://www.avast.com/antivirus
>>>>>> 
>>>>>> --
>>>>>> Coco mailing list
>>>>>> Coco at maltedmedia.com
>>>>>> https://pairlist5.pair.net/mailman/listinfo/coco
>>>> 
>>>> ---
>>>> This email has been checked for viruses by Avast antivirus software.
>>>> https://www.avast.com/antivirus
>>>> 
>>>> 
>>>> --
>>>> Coco mailing list
>>>> Coco at maltedmedia.com
>>>> https://pairlist5.pair.net/mailman/listinfo/coco
>>> 
>> 
>> 
>> ---
>> This email has been checked for viruses by Avast antivirus software.
>> https://www.avast.com/antivirus <https://www.avast.com/antivirus>
>> 
>> 
>> --
>> Coco mailing list
>> Coco at maltedmedia.com <mailto:Coco at maltedmedia.com>
>> https://pairlist5.pair.net/mailman/listinfo/coco 
>> <https://pairlist5.pair.net/mailman/listinfo/coco>


More information about the Coco mailing list