Philipp Klaus Krause <pkk@spth.de> writes:
> A video game cartridge. Containing the EPROM (program and data), EEPROM
> (for savegames) and CPLD (bank switching, access to I&sup2;C).

Even if there was a single-chip solution for that (which there isn't),
it would cost *much* more than a multichip solution.

Evan Lavelle schrieb:
> On Tue, 31 Jul 2007 13:36:03 +0200, Philipp Klaus Krause <pkk@spth.de>
> wrote:
> 
>> It goes into a Z80-based system from the 80s. 
> 
> What is it?
> 
> Evan

A video game cartridge. Containing the EPROM (program and data), EEPROM
(for savegames) and CPLD (bank switching, access to I&#4294967295;C).

Philipp

On Tue, 31 Jul 2007 13:36:03 +0200, Philipp Klaus Krause <pkk@spth.de>
wrote:

>It goes into a Z80-based system from the 80s. 

What is it?

Evan

Philipp Klaus Krause wrote:
> Jim Granville schrieb:
> 
>>>The device doesn't have to be fast, 8 Mhz for a simple design would be
>>>OK. I need about 40 I/O.
>>
>>What does this connect to ? - ie where does this ROM code go ?
>>Is there a processor in the system, reading this, or something else ?
> 
> 
> It goes into a Z80-based system from the 80s. The system has a cartridge
> port, where D0...D7 (data), A0...A14 (addres bus, A15 missing), E8...EE
> (chip enable). Back in the 80s a cartridge would contain one to four 64
> KBit EPROMS containing a program. Each enable line would be used as a
> chip enable.
> I've written a few programs for the system. So far each did fit into
> 32KB, so I used a 256 KBit EPROM together with a 74LS21 (to connect the
> four chip enable lines to the EPROM's output and chip enable) for my
> cartridges.
> Now I'd like to write a program that uses more ROM and I'd like to be
> able to save some data. I think dividing the address space into lower
> 24KB (directly mapped as before) middle 4KB (bank-switched), upper 4KB
> (to locate some control registers to switch the middle 4KB and control
> the I&#4294967295;C line to the EEPROM) would make sense.

Have you looked at FLASH rather than EPROM ?
Then you might be able to dispense with the EEPROM.
If you use a small CPLD (XC9536, or ATF1502ASL ) you will
be able to do all the chip select/banking/mapping you need,
as well as get a phantom write path for the Flash.

-jg

Philipp Klaus Krause <pkk@spth.de> writes:
> I'm looking a PLD with 5V TTL-compatible I/O that has ~2Mb of integrated
> memory that can be used as ROM and ~64Kb of integrated memory that can
> be used as EEPROM.

You're going to be looking for a long time.

You can get that much RAM, but not in a part with 5V tolerant I/O.

You can get built-in flash memory, but not EEPROM.

I suspect that you just need to use a 3.3V part with appropriate level
shifters or QuickSwitch parts (or equivalent) to get your 5V tolerance
(or possibly just series resistors), and a separate EEPROM chip.

Jim Granville schrieb:
>> The device doesn't have to be fast, 8 Mhz for a simple design would be
>> OK. I need about 40 I/O.
> 
> What does this connect to ? - ie where does this ROM code go ?
> Is there a processor in the system, reading this, or something else ?

It goes into a Z80-based system from the 80s. The system has a cartridge
port, where D0...D7 (data), A0...A14 (addres bus, A15 missing), E8...EE
(chip enable). Back in the 80s a cartridge would contain one to four 64
KBit EPROMS containing a program. Each enable line would be used as a
chip enable.
I've written a few programs for the system. So far each did fit into
32KB, so I used a 256 KBit EPROM together with a 74LS21 (to connect the
four chip enable lines to the EPROM's output and chip enable) for my
cartridges.
Now I'd like to write a program that uses more ROM and I'd like to be
able to save some data. I think dividing the address space into lower
24KB (directly mapped as before) middle 4KB (bank-switched), upper 4KB
(to locate some control registers to switch the middle 4KB and control
the I&#4294967295;C line to the EEPROM) would make sense.

Philipp

Philipp Klaus Krause wrote:

> Philipp Klaus Krause schrieb:
> 
>>I'm looking a PLD with 5V TTL-compatible I/O that has ~2Mb of integrated
>>memory that can be used as ROM and ~64Kb of integrated memory that can
>>be used as EEPROM.
>>
>>Initially I considered using a parallel EPROM, serial EEPROM together
>>with lots of TTL, but soon I realized that the EPROM, EEPROM together
>>with a 22V10 GAL and a 74573 register would be a simpler solution.
>>A few days ago I noticed how cheap CPLDs are today and that one,
>>together with a 3.3V voltage regulator could replace the GAL and register.

Correct. 22V10 + '573 => 32 macrocell CPLD.

>>
>>Now I ask myself if there is some PLD that could replace the EEPROM or
>>EPROM, too.

Yes, but not to 2Mb of memory.

> The device doesn't have to be fast, 8 Mhz for a simple design would be
> OK. I need about 40 I/O.

What does this connect to ? - ie where does this ROM code go ?
Is there a processor in the system, reading this, or something else ?

-jg

Antti schrieb:

> hm, ST has some products based on waferscale stuff, they all include
> some flash and smallish PLD, but I guess they will not directly match
> your needs either

ST's PSD would do feature-wise, but they seem to be rather expensive.
The cheapest I found at digikey is at ~7&euro;, current solution would be ~3&euro;
(XC9536XL: 0.8 &euro;, 2Mb EPROM: 1&euro;, voltage regulator: 0.6&euro;, EEPROM: 0.3&euro;)
(all proces per piece when ordering 100).

Philipp

On 31 Jul., 11:19, Philipp Klaus Krause <p...@spth.de> wrote:
> Philipp Klaus Krause schrieb:
>
> > I'm looking a PLD with 5V TTL-compatible I/O that has ~2Mb of integrated
> > memory that can be used as ROM and ~64Kb of integrated memory that can
> > be used as EEPROM.
>
> > Initially I considered using a parallel EPROM, serial EEPROM together
> > with lots of TTL, but soon I realized that the EPROM, EEPROM together
> > with a 22V10 GAL and a 74573 register would be a simpler solution.
> > A few days ago I noticed how cheap CPLDs are today and that one,
> > together with a 3.3V voltage regulator could replace the GAL and register.
>
> > Now I ask myself if there is some PLD that could replace the EEPROM or
> > EPROM, too.
>
> > Philipp
>
> The device doesn't have to be fast, 8 Mhz for a simple design would be
> OK. I need about 40 I/O.
>
> Philipp

the only devices with onchip user flash are Actel Fusion and Lattice
XP2 but they are not 5V tolerant.
there is and will not be any single chip solution that is 5V tolerant
meets your needs.

hm, ST has some products based on waferscale stuff, they all include
some flash and smallish PLD, but I guess they will not directly match
your needs either

Antti

Philipp Klaus Krause <pkk@spth.de> writes:

> I'm looking a PLD with 5V TTL-compatible I/O that has ~2Mb of integrated
> memory that can be used as ROM and ~64Kb of integrated memory that can
> be used as EEPROM.

The Altera Max-II has 8Kb FLASH memory if that can be of any help:

http://altera.com/products/devices/cpld/max2/features/flash/mx2-flash_memory.html

Petter
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