320k Parallel Port RAM Upgrade for 600XL & 800XL

[BillC]

46 minutes ago, Larry said:

Makes a very simple ram upgrade and coupled with a switchable OS, would give great user flexibility.  

Too bad it doesn't include an external OS option, similar to the SYSCHECK 2.x devices, as well.

[reifsnyderb]

1 hour ago, Larry said:

Wonder if Ctirad, the guy who sold the Ram 320XL, still lurks here?  I hope this new version is successful.  Makes a very simple ram upgrade and coupled with a switchable OS, would give great user flexibility.  Truth be told, the disk-based translators do a good job, but flipping a switch is even better. 

 

@reifsnyderb, have you tested ram-under-rom software (like Turbo Basic XL) to make sure it still works?  I don't know why it wouldn't but it's easy to test.

I've got an Atari Translator disk and can try that later.  I don't see any reason it shouldn't work, though, as the base memory's use is selected by the MMU chip.

[reifsnyderb]

25 minutes ago, BillC said:

Too bad it doesn't include an external OS option, similar to the SYSCHECK 2.x devices, as well.

Well, now that you mention it, making more complicated PBI boards is on my "to-do" list.  I started out working on more complicated PBI boards but ran into problems such as CPLD shortages and a rather steep learning curve.  When you add contradictory documentation into the mix it makes it even worse.  So, I back-tracked and started getting glue logic boards working first as the 74x chips aren't as affected by the chip shortages.  But they are much harder to deal with mistakes as the fix involves hacking the board as opposed to just changing the program.  I am also documenting what I've learned and gathered together from various sources.  I plan on releasing that document once it is more useful.

Edited July 1, 2022 by reifsnyderb

[BillC]

46 minutes ago, reifsnyderb said:

Well, now that you mention it, making more complicated PBI boards is on my "to-do" list.  I started out working on more complicated PBI boards but ran into problems such as CPLD shortages and a rather steep learning curve.  When you add contradictory documentation into the mix it makes it even worse.  So, I back-tracked and started getting glue logic boards working first as the 74x chips aren't as affected by the chip shortages.  But they are much harder to deal with mistakes as the fix involves hacking the board as opposed to just changing the program.  I am also documenting what I've learned and gathered together from various sources.  I plan on releasing that document once it is more useful.

The chip shortages could be part of what has delayed the external U1MB device, development of which was announced about 1.5 years ago, as well.

That device combines the features of the 1064 and U1MB, plus adding a memory card slot.

Edited July 1, 2022 by BillC

[Frankie]

Does it have a blinking LED like RAM 320XL does? Blinking LEDs is HI-TECH! ?

 

[+DrVenkman]

13 minutes ago, Frankie said:

Does it have a blinking LED like RAM 320XL does? Blinking LEDs is HI-TECH! ?

 

You better believe it, buddy!

 

[reifsnyderb]

51 minutes ago, Frankie said:

Does it have a blinking LED like RAM 320XL does? Blinking LEDs is HI-TECH! ?

 

?

 

Well, I was going to suggest adding a 555 timer with a potentiometer to adjust the blink rate but @DrVenkman beat me to it. 

 

What would a blinking LED be connected to anyhow and why?

[+mytek]

29 minutes ago, reifsnyderb said:

What would a blinking LED be connected to anyhow and why?

Well obviously to show that the RAM is being scanned

 

[ivop]

It could be sold as a kit. A pick me up kitt.

 

[Peri Noid]

Is this expansion supposed to provide also the additional 48K of basic RAM that a 600XL is missing? 

[reifsnyderb]

4 hours ago, Peri Noid said:

Is this expansion supposed to provide also the additional 48K of basic RAM that a 600XL is missing? 

On a 600XL, this expansion completely replaces the 16k of base RAM with 48k of base RAM.  It also shadows $D301 (PORTB) in order to enable banking if bit 4 is set to 0.  Banking is done via bits 2, 3, 5, and 6.  The SRAM chip used is actually 512k but only 320k is used.  The rest of the circuitry is used to interface the SRAM chip, for timing, and for banking.

 

To make things simple, on an 800XL, this expansion functions the same as on a 600XL and replaces the 800XL's DRAM with the on-board SRAM.

 

 

Edited July 2, 2022 by reifsnyderb

[reifsnyderb]

Too late to edit but my last post should have read:

 

On a 600XL, this expansion completely replaces the 16k of base RAM with 64k of base RAM.  It also shadows $D301 (PORTB) in order to enable banking if bit 4 is set to 0.  Banking is done via bits 2, 3, 5, and 6.  The SRAM chip used is actually 512k but only 320k is used.  The rest of the circuitry is used to interface the SRAM chip, for timing, and for banking.

 

To make things simple, on an 800XL, this expansion functions the same as on a 600XL and replaces the 800XL's DRAM with the on-board SRAM.

[masteries]

Is this RAM expansion suitable for XE models too?

[Peri Noid]

5 hours ago, reifsnyderb said:

On a 600XL, this expansion completely replaces the 16k of base RAM with 48k of base RAM.

Only 48K? What about the rest? One can completly turn off both Basic and OS so it should be full 64K (only 2KB of hardware registers remain so 62K actually).

[reifsnyderb]

5 hours ago, masteries said:

Is this RAM expansion suitable for XE models too?

I think an adapter could be made a 130XE.  I don't have one to check it with though.  If somebody wants to send me one, I'll happily make up an adapter for a 130XE.

Edited July 2, 2022 by reifsnyderb

[reifsnyderb]

1 hour ago, Peri Noid said:

Only 48K? What about the rest? One can completly turn off both Basic and OS so it should be full 64K (only 2KB of hardware registers remain so 62K actually).

It will do the full 64k (ok, really 62k).  48k was a typo.

[Peri Noid]

Oh, so it would be something I'd like. I have a RAM 320XL expansion and it adds only the additional 256KB.

[reifsnyderb]

10 minutes ago, Peri Noid said:

Oh, so it would be something I'd like. I have a RAM 320XL expansion and it adds only the additional 256KB.

If I understand you correctly, then, yes, my expansion has a full 320k.  It is 64k base memory + 256k expanded memory.

[archeocomp]

9 hours ago, Peri Noid said:

Oh, so it would be something I'd like. I have a RAM 320XL expansion and it adds only the additional 256KB.

You have to talk Lotharek into doing this. ? We need something like this in Europe too.

[reifsnyderb]

I finally received the surface mount 0.33pF capacitor yesterday and installed the capacitor as well as the USB-C connector.  (The USB-C connector is for use with an 800XL that does not have PBI power...which should be most of them.)  The jumper on the back side is to enable the USB-C external power.  On the left side of the front is also a place where someone could solder a couple wires if, for example, they want to rig up power from a joystick port.

 

Testing on both the 600XL and 800XL is successful.

 

Here's some pictures showing the module with a 600XL.  SimpleCheck and SpartaDOS X are also shown.

 

 

 

 

 

 

 

 

 

[+x=usr(1536)]

Ooooh, very likeable

 

Dumb question: if a 600XL already has an internal 64K upgrade, would it just behave as though it were connected to an 800XL?  I feel like I've missed something about how this would work from reading back through the thread.

 

Of course, there's always the temptation on a 16K machine to piggyback it off of a 1064 and see what happens

[reifsnyderb]

8 minutes ago, x=usr(1536) said:

Ooooh, very likeable

 

Dumb question: if a 600XL already has an internal 64K upgrade, would it just behave as though it were connected to an 800XL?  I feel like I've missed something about how this would work from reading back through the thread.

 

Of course, there's always the temptation on a 16K machine to piggyback it off of a 1064 and see what happens

Yes, if the 600xl has been upgraded to 64k it should be like connecting the 320k upgrade to an 800xl.  Unlike a normal 800xl, the 600xl will provide internal power to it.

 

I don't see how you'd connect both a 1064 and this upgrade without some really creative wiring.

 

[+scorpio_ny]

Hi @reifsnyderb,

 

Will this item be available for sale soon?

 

[reifsnyderb]

1 hour ago, scorpio_ny said:

Hi @reifsnyderb,

 

Will this item be available for sale soon?

 

Hello,

 

I put some out on Tindie and ebay.  My Tindie store is in my signature.  I didn't put anything out on my web site as it doesn't get much traffic.  I am not sure as to whether to get rid of the website or to get a better domain name as the current domain name was re-used from a previous project of mine.

 

Thanks!

 

Brian

 

[Beeblebrox]

2 minutes ago, reifsnyderb said:

Hello,

 

I put some out on Tindie and ebay.  My Tindie store is in my signature.  I didn't put anything out on my web site as it doesn't get much traffic.  I am not sure as to whether to get rid of the website or to get a better domain name as the current domain name was re-used from a previous project of mine.

 

Thanks!

 

Brian

 

@reifsnyderb  Are you able to pop up a link to the ebay listing?