thoughts on Digitech Space Station eprom copying?

[nochtanseenspecht]

the person i got the eproms from, burned both the .BIN files (xp200 and xp300) on one eprom 27512
he says they fit both on one eprom and i can enable each by connecting pin 27 either to 5V or to ground.
would that work you think?

You can always try. It will be a gamble though as the XP series was built and programed to use the 27C256 series EPROMs.

If you decide to try.... definitely report back! Enquiring minds WANT TO KNOW!  

ok, here's my report from across the ocean :
i got my xp working with the 27512 ..YES!! the 27512 got both the xp20 and 300 wich can be activated with a switch from pin 1 to either pin 14 or (an 1K resitor in series with) pin 28 . so that means that with two 27512 eproms you can cover the whole xp series 
thanks a lot Govmnt_Lacky and digi2t for all great explanations!
and now.... time for music!

[Govmnt_Lacky]

EXCELLENT NEWS!!!!

Any chance you could share how the chips were programmed? How were you able to load BOTH programs on the chip?

If you can share this info then it can be added to the build documents for others to use 

Thanks!!!

[digi2t]

 

Please, do explain the programming process to get 2 programs on the 27C512. I've read that tuners do it to have two different performance programs on tap at the flip of a switch.

That could mean two chips = XP ALL.

That's just toooo cooooool  .

Time to research.....

[nochtanseenspecht]

unfortunately i have to admit that i don't know anything about programming,
i got the EPROM of a local advertisement site, and the man did the programming for free, i provided him with the .BIN files you shared here.
he told me he put the xp200 on the low side and the xp300 on the high side and thats all i know   
i could ask him how he did it if you like?
anyways its late here, i must sleep,
but tomorrow i will draw you a schematic how to connect the 27512 the proper way
cheers david

[digi2t]

unfortunately i have to admit that i don't know anything about programming,
i got the EPROM of a local advertisement site, and the man did the programming for free, i provided him with the .BIN files you shared here.
he told me he put the xp200 on the low side and the xp300 on the high side and thats all i know   
i could ask him how he did it if you like?
anyways its late here, i must sleep,
but tomorrow i will draw you a schematic how to connect the 27512 the proper way
cheers david

OK David. I believe that I've got the programming side of things figured out. As a matter of fact, I found a neat program that appends up to 4 programs for you, and outputs a .bin file when done.

The wiring would be interesting to see. I found info on that as well, but it will be nice to validate it with what you have.

Cheers,
Dino

[nochtanseenspecht]

ok here's how i wired it, works perfect:

[nochtanseenspecht]

in this wiring there's only 3 xp modes available, (as i was not interested in the xp400)

[digi2t]

Excellent David. Thanks a ton for the drawing. It does validate to a great extent my research on loading the 4 programs on one chip.

Thank you very much for taking your time to draw it out, and posting it.

Cheers,
Dino

[pinkjimiphoton]

kudos all around to all you crazy sons of...

i have been getting more familiar with this pedal daily, and it's kinda blowing my mind.

if we could midify it, just so you could select whatever patch you need, it would be absolutely perfect.

so... does this mean with david's mod, all 4 xp's will be able to share one chip?

this gets cooler by the minute! <pink grabs some popcorn to camp out>

[nochtanseenspecht]

Excellent David. Thanks a ton for the drawing. It does validate to a great extent my research on loading the 4 programs on one chip.

Thank you very much for taking your time to draw it out, and posting it.

Cheers,
Dino

You're welcome, Dino 
wow..all four on one chip that would be so wonderfull

btw i had a failure last night , the pedal didn't respond anymore
it was frightening, but luckily after recallibration it rocks fine again

[digi2t]

kudos all around to all you crazy sons of...

i have been getting more familiar with this pedal daily, and it's kinda blowing my mind.

if we could midify it, just so you could select whatever patch you need, it would be absolutely perfect.

so... does this mean with david's mod, all 4 xp's will be able to share one chip?

this gets cooler by the minute! <pink grabs some popcorn to camp out>

Not quite, the 27C512 can only hold 2 programs max. That means you still need to piggyback chips, BUT......

I'm currently working on retro fitting a larger 1mBit chip in here, that will hold all four programs. The programs will be "hot" switchable, as the XP-ALL is. It will also streamline the XP-ALL mod process in the sense that there will be no chip piggybacking, only one chip to program, and the mod process will be identical for all XP series pedals. The switch I'm looking at using will also allow LED indication of which mode you're in. Yup... that's the plan.

Also, I'm experimenting with a mod to restore the stereo to the XP-ALL in 100 mode. It should be applicable to present, and future XP-ALL models, using already existing board thru-holes, and switch poles. You'll be able to either mount the component onto a small piece of veroboard and screw it in, or simply glue it into the unit somewhere. This should restore the XP-100 mode to it's original stereo configuration.

Jeez my drawing board is FULL!

@David - The factory reset is "de rigeur" after a mod. I found that the units are never stable after a mod, and may seem to work fine, but crash at some point. A factory reset generally tends to settle out any problems. I mention it in the build document, but I think I should do a rewrite here to stress the need for one after a mod a bit more.

[nochtanseenspecht]

ah i see.. i must have missed that when i studied your document.
i also used a switch that is wired to LED's to show wich mode you're in.. nice

only i couldn't find the low voltage detector in my neighborhood, so i was thinking to just cut one diode from the bridge and wire that to the mode switch (there are some free poles available still) in order to make a powercycle while changing to an other mode, so i don't have to take out the power connector after mode changing (like you described)
would that work you think?i mean to make use of an diode instead of the low voltage detector (u13)

[markeebee]

I'm currently working on retro fitting a larger 1mBit chip in here, that will hold all four programs. The programs will be "hot" switchable, as the XP-ALL is. It will also streamline the XP-ALL mod process in the sense that there will be no chip piggybacking, only one chip to program, and the mod process will be identical for all XP series pedals. The switch I'm looking at using will also allow LED indication of which mode you're in. Yup... that's the plan.

I won an XP100 on ebay last week, and I was feeling a bit ticked off that it hasn't arrived yet.  Then I read this post, and of course I'm gonna wait to see your new mods, so I'm kinda happy that I haven't received and modded/broken it yet. 

Thanks Dino.

[digi2t]

I'm currently working on retro fitting a larger 1mBit chip in here, that will hold all four programs. The programs will be "hot" switchable, as the XP-ALL is. It will also streamline the XP-ALL mod process in the sense that there will be no chip piggybacking, only one chip to program, and the mod process will be identical for all XP series pedals. The switch I'm looking at using will also allow LED indication of which mode you're in. Yup... that's the plan.

I won an XP100 on ebay last week, and I was feeling a bit ticked off that it hasn't arrived yet.  Then I read this post, and of course I'm gonna wait to see your new mods, so I'm kinda happy that I haven't received and modded/broken it yet. 

Thanks Dino.

Mark, sit tight on it for now. I'm waiting on parts for possibly a fairly substantial revamp on the conversion method. Let me get my stuff, and do my testing. I'll let you know the best route to take.

[Dirk_Hendrik]

Multiple firmwares in 1 Eprom.

A 1 megbit eprom is 4 times as large as a 256kbit eprom. Therefore to be able to adress all memory locations one will need 2 extra adress lines. Look up the differences between a 27C256 and a 27C010 eprom and you'll see the difference is that it has an A15 and A16 adress line that thew 256 lacks. 

Now, to get all XP firmwares in an eprom one will have to make a new binary file that contains all 4 XP eprom images with a hex editor. It is important that the start of the binary data for a "next" image starts at the right adress.

The XP100 image starts at adress 00000hex
The XP200 image starts at adress 08000hex
The XP300 image starts at adress 10000hex
The XP400 image starts at adress 18000hex


After this, by selecting binary 00, 01, 10 or 11 on the A15 and A16 lines one selects which XP binary is loaded upon reset. And you'll need to make a converter board that ports the A0 upto A14 adress lines, the control bus and the databus for a 27C010 to a 27C256 size that connects to the XP board. Which I prefer far above the piggybacking.

[digi2t]

Multiple firmwares in 1 Eprom.

A 1 megbit eprom is 4 times as large as a 256kbit eprom. Therefore to be able to adress all memory locations one will need 2 extra adress lines. Look up the differences between a 27C256 and a 27C010 eprom and you'll see the difference is that it has an A15 and A16 adress line that thew 256 lacks. 

Now, to get all XP firmwares in an eprom one will have to make a new binary file that contains all 4 XP eprom images with a hex editor. It is important that the start of the binary data for a "next" image starts at the right adress.

The XP100 image starts at adress 00000hex
The XP200 image starts at adress 08000hex
The XP300 image starts at adress 10000hex
The XP400 image starts at adress 18000hex


After this, by selecting binary 00, 01, 10 or 11 on the A15 and A16 lines one selects which XP binary is loaded upon reset. And you'll need to make a converter board that ports the A0 upto A14 adress lines, the control bus and the databus for a 27C010 to a 27C256 size that connects to the XP board. Which I prefer far above the piggybacking.

Thanks for the info Dirk.

Insofar as arranging the firmware is concerned, there is already an app available on the net for arranging this, specifically aimed at the 27C1001. You simply plug in the bin files you wish to combine, and the app outputs a bin file, properly spaced, and in the order you wish them to be in. No messing with hex editing.

At the moment, I don't believe a converter board will be necessary. A proper switching scheme should accomplish the job. Tuners have been using the switch scheme for a long time now.

I'll report my findings when I'm done testing.

BTW, thanks for enlightening us on the "power on reboot scheme". Very kind of you. 

Cheers,
Dino

[rocket]

I have just successfully modded an XP400 to XP300.
Just had to add 1 RAM (Vishay) , 3 are already there, also the 4th socket is in place.
And change the rom to an xp300-eprom.

--> completly solder free.

As the XP400 was 110€ (>$130) I am not quite sure if the easier mod justifies the higher price(compared to xp100,200), especially if you go for the XP-all

Anyway - IT'S WORTH IT!!

[Govmnt_Lacky]

As the XP400 was 110€ (>$130) I am not quite sure if the easier mod justifies the higher price(compared to xp100,200), especially if you go for the XP-all

A lot better than the $350-400 that the 300s go for on fleabay 

[digi2t]

Share the knowledge, share the joy.

Good job rocket! 

[LP Hovercraft]

I just got my 10+ years abandoned, broken, and disassembled xp100 working again tonight.  I can't wait to get started!