Re: 6809 assembly knowledge needed

From: Jim Brain <>
Date: Thu, 04 Feb 2010 08:45:59 -0600
Message-ID: <>
On 2/4/2010 4:38 AM, Rainer Buchty wrote:
> - The PDF says: "I/Os are not 5V tolerant". I see a lot of resistors 
> to handle this. But is it still capable of driving the C64 plus some 
> extras? If not, what is needed to make it capable? For example, will 
> 74HCT245's and 541's do?
> You don't need extra level shifters as GODIL comes readily equipped 
> with such. These you can use (adds 700ps to the timing path), but you 
> don't need to in case you don't require 5V tolerance.
GODIL's use of 74CB3T16211 level shifters was good information.  I'd 
been looking at the 5V I/O tolerance issue and the fact that series 
resistors were problematic.
> Btw., if there are special feature requests or ideas for improvement 
> regarding future versions of GODIL, let me know and I'll happily 
> forward it to Mike Randelzhofer, the developer of GODIL (whom I'd like 
> to thank for donating me first-batch sample).
It seems like a smaller version for final use might be worth the 
trouble.  The current product looks like a swiss army knife, with USB, 
header pins, etc., but if one of the goals is to replace a 40/48 pin DIP 
IC, that item might not fit in some situations.

For what it's worth, I'm finally getting my feet wet with programmable 
logic.  I put it off before because I knew it'd would be a non trivial 
time investment to learn a language and a new way to implement HW 
designs, but the economic aspect drove me in this direction.  Many of 
the project ideas I have cannot be economically created with discrete 
logic, and there are some features of existing projects (Link232 having 
Turbo232 compatibility) that fit best with programmable logic (the T232 
has GALs to implement its functionality).  I've chosen Verilog, since 
I'm a 'C' guy, and I grabbed Icarus Verilog to learn the ropes before 
fighting with vendor tools, though I downloaded the vendor tools as well 
(I used the schematic editor in the Xilinx tool to prove out an idea for 
one project, but quickly decided the schematic editor was less than 
ideal for programmable logic definition).


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Received on 2010-02-04 16:00:04

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