RE: FPGA/CPLD different approach

From: Bil Herd <>
Date: Mon, 26 Aug 2013 10:06:26 -0400
Message-ID: <>
Correct, the Altera line needs an external source to load from (I still call
it the font but I am probably wrong).  I have done a design were the FPGA
was $1 and the eeprom was $10, which just sucked.

Altera CPLD don’t need to be loaded every power cycle.

Altera is coming out with flash based devices next year according to the FE
for my area.

I usually do away with the EEPROM if there is another processor nearby, for
example if the design is on a PCI card I make the main system program the
FPGA via a JTAG-like port.  Also makes it easy to reprogram hardware in the

-----Original Message-----
[] On Behalf Of
Sent: Monday, August 26, 2013 9:22 AM
Subject: Re: FPGA/CPLD different approach

On 2013-08-26, at 14:38, Michał Pleban wrote:

>> I understand. What If I forget the CPU emulation and want to build only
>> some RAM, ROM and one or two 8bit bi-directinal I/O ports, all available
>> for the original CPU to interact with - what would you suggest? Can one
>> easily make such structures (RAM, ROM, I/O port) available for 6502 from
>> within a CPLD/FPGA and which would be "better" in such case?
> ROM and RAM are costly in terms of re-programmable logic. If you need
> these, you will end up using a FPGA anyway.

Why is it so? I read somewhere in Altera docs that /ROM/ is not available in
[their MAX series] CPLDs. Does that mean it is not available in /any/ of
them? Sorry if that's a n00b question but I also read somewhere that FPGAs
have to be given some external boot rom, while CPLDs don't.

> If you need only I/O, then you can use a CPLD as well, there are still
> 5V ones available (though more expensive than 3.3V).

Like the "original" Altera MAX I guess?

For what I think of doing I'd need about a dozen of chips. RAM, ROM, I/O and
some glue as well. When I counted those, it triggered me to eventually start
thinking of putting all of those into one chip, presumably only with some
level adapters like on the GODIL and am now trying to learn enough to make
somewhat educated decision...

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Received on 2013-08-26 15:01:16

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