Date   : Mon, 05 Apr 2010 16:20:38 +0100
From   : etljwk@... (John Kenyon)
Subject: ReTuLa, a Tube ULA

John Kortink wrote:
> On Mon, 05 Apr 2010 00:19:05 +0100, Phill Harvey-Smith
> <afra@...> wrote:
>
>   
>> John Kortink wrote:
>>     
>>> Okay, 'first silicon', so to speak :
>>>
>>> http://web.inter.nl.net/users/J.Kortink/home/hardware/retula/retula_big.jpg
>>>
>>> Outweighs the original at slightly over 10 grams,
>>> yet lighter on the FIFO bytes ... More to follow.
>>>       
>> Humm, unless I'm not really understanding things isn't a 64 macrocell 
>> CPLD a little small to implement the tube ULA ?
>>     
>
> Only to implement all 20 'VDU FIFO' bytes.
>
> But even with just one byte, pumping VDU data through at
> full speed is, in practice (e.g. back-to-back character
> printing, Tube Elite), only a 3 to 4% performance hit.
>
> The design takes a 128 macrocell CPLD as well, so there's
> still room for a handful of VDU FIFO bytes, if necessary
> (although not all 20).
>
>   
>> Asuming you do get it going are you going to share the design ?
>>     
>
> It's already 'going', Phil, working fine in ReCo6502, and
> in both Acorn 6502 2p contraptions. And no.
>
>
> John Kortink
>
>   
I hope that "no" means you aren't going to share the CPLD code, but you 
will sell the devices separately.

/John