[Coco] FPGA 6809

Dave Philipsen dave at davebiz.com
Mon Aug 31 14:43:25 EDT 2015


A correction to my previous post:  This board does not do TCP/IP via 
RS232.  It uses NRZ LVTTL (3.3v) to communicate with the host.


On , Dave Philipsen wrote:
> www.ebay.com/itm/221815784082?
> 
> 
> 
> On , Mathieu Chouinard wrote:
>> Any link?
>> 
>> On Mon, Aug 31, 2015 at 1:43 PM, Bill Nobel <b_nobel at hotmail.com> 
>> wrote:
>>> Yes, I have seen those on e-bay been planning to get a few of them 
>>> myself.
>>> 
>>> Bill Nobel
>>> 
>>>> On Aug 31, 2015, at 10:58 AM, Dave Philipsen <dave at davebiz.com> 
>>>> wrote:
>>>> 
>>>> 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
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