thoughts on Digitech Space Station eprom copying?

[marmaliser]

Hmmmm, a bit more testing actually with an amp this time and looking at the effect numbers shows that I have

Position 1 = XP100 Whammy
Position 2 = Nothing get -- on screen and then switches off
Position 3 = XP200 modulator
Position 4 = XP400 Reverb

EDIT - Noticed that my xp100's first  ram slot is a 61464c which is different to the other 3 I installed (41464c) .  Looking at the datasheets they appear to be different .  Is this the problem as the XP300 needs more ram .  d2t said "For the RAM, three more of the same as what you've got in there now, or four D41464C"

[digi2t]

According to the schematics, the RAM requirements for each model is as follows;

XP-100 - one chip.
XP-200 - one chip.
XP-300 - four chips.
XP-400 - three chips.

As for the 61464, it might be the problem. I've been scanning over the datasheets, but to my eye, they look pretty much the same. There might be something that is preventing them from interacting though. Personally, I would go with 4 identical chips, just to be sure. In the meantime, double check all your connections.

Also,

Position 1 = XP100 Whammy
Position 2 = Nothing get -- on screen and then switches off
Position 3 = XP200 modulator
Position 4 = XP400 Reverb

Is this the actual order that you have now? Shouldn't 200 mode be in "Position 2", and 300 mode in "Position 3"?

[marmaliser]

Yep XP 200 is deffo in slot 3. I have verified this by checking the volume pedal programme numbers just to be sure

I have checked the switching and i get the same as you per page 11
"A14  A15  A16
0      0      0   = XP100
0      0      1   = XP200
1      1      0   = XP300
1      1      1   = XP400"

Except i have nothing in p2 and xp200 in p3  WEIRD !!!!

Checked the switch wiring at least 10 times and it looks  ok.  Also the adapter board checks out.

[Govmnt_Lacky]

I have never used any other RAM chips other than the D41464s and, for a short time, I used some TMS version that I cannot remember the exact numbers but I did my diligence and found they were identical.

I HIGHLY recommend that you install D41464-10 RAM chips for EVERY slot. DO NOT mix and match versions and speeds.

Also, if your pedal works in XP400 mode then it "should" work in 100 and 200 mode as the same RAM chips are in use.... just less of them. XP100 and 200 uses the chip in slot U19. The XP400 uses U19, U18, and U17. The XP300 uses all 4 of them.

Personally... I think you have 2 problems. Mismatched RAM chips -AND- bad programming on your 27C1001 

[marmaliser]

Thanks for the continued input guys. 

Burnt another 27c010a today. Checked it back in the programmer and also read it back to a Bin file which i confirmed using an Hex editor to be an exact match  sadly still got the same result.

I had a 256 chip so burnt the XP300 onto that and plugged it straight in.  That worked fine

So it must be the adapter board, wiring or switch that is the problem.  .......Off to check it all again.

[Govmnt_Lacky]

Burnt another 27c010a today. Checked it back in the programmer and also read it back to a Bin file which i confirmed using an Hex editor to be an exact match...

Well... if the 256 chip worked fine, then it can only be 3 things...

1) Your adapter board has issues.
2) Your wiring is not correct
3) The way you are programming your 1001 chip is not correct. (This is where my money is) 

The fact that you said your XP100, XP400, and XP200 programs were working fine tells me that it "shouldn't" be your adapter board and "probably" not your wiring.

This leaves #3 

Let us know.

Good Luck 

[marmaliser]

Just looking at making a vero adapter and I could be wrong but isn't the connection R1 / A14 on the wrong row ?  (looks like A13 to me)

[Govmnt_Lacky]

Just looking at making a vero adapter and I could be wrong but isn't the connection R1 / A14 on the wrong row ?  (looks like A13 to me)

There is a great example of the vero in Dino's build document. Page 47. Its in the gallery bro 

[marmaliser]

Just looking at making a vero adapter and I could be wrong but isn't the connection R1 / A14 on the wrong row ?  (looks like A13 to me)

There is a great example of the vero in Dino's build document. Page 47. Its in the gallery bro  

i know its been hard work to get me this far but lol, i aint that stupid. Thats the one i was referring to (should have said though).  I think there may be an error on it. 

[Govmnt_Lacky]

Gotcha! 

I do believe you are correct sir! It looks like R1 needs to be moved up one row to coorespond to A14 on both chips. Right now, it is connected to A13 of both chips!


PAGING DOCTOR DIGI2T!!! 

Does this mean that the fabbed adapter boards are not going to work? 

[marmaliser]

Does this mean that the fabbed adapter boards are not going to work? 

I based mine on the perf so this doesn't impact on it and it does connect all the right pins. 

I will be building the vero tonight (corrected) so I can pin my problem down a bit more.  I have another XP100 coming tomorrow so want to get this sorted.

[digi2t]

Hi guys,

First off, a disclaimer; I`m writing this from memory, since I looked at things last night and this morning. I`m at work right now, so I don`t have things in front of me. Hence...

A) The vero is incorrect where R1 is concerned. Why? I based my layout on a «hole for hole» transfer from the perf, and since I wanted R1 to lay flat, on the perf I could «up and over» my trace to the pin above. I neglected this detail on the vero. Pin connection for R1 should be up one hole on the vero. The perf is correct though, I eyeballed it with my unit. The vero will be corrected tonight, and the build doc updated.

B) While I was on things, I believe there is an error with the OSH Park board. To my eyes, there is a trace missing between pin 32 of the 27C1001, and pin 28 of the 27C256 header. This is the Vcc supply, which is critical, especially considering that R1 is fed from here, so it has no connection to Vcc either. The other end of R1 connection looks fine, as well as the other three resistors, since it looks like it was based off the perf version, and not the vero. I would appreciate a validation on this, and if so, the OSH board will require a jumper between these two points. This is most likely the reason for which position two on your unit is not booting up, and MIGHT be the reason why XP-200 mode is booting up in position three.

In the end, there was a little right, and a little wrong, on both sides. Just remember folks, in the end, we`re all human, and sometimes logic can become a fleeting thing in the face of difficult situations. Statements such as;

i know its been hard work to get me this far but lol, i aint that stupid.

are counterproductive, and only serve to blind further. I prefer to try and fit my pieces into the pieces that other bring to the table instead. Collectively, even the most inexperienced people can serve to expand the vision of the experienced.

Amen.

[marmaliser]

Amen.  Sorry I was self-deprecating to make light of my earlier wiring blindness

Below is an image from Diptrace that shows the connections to pin 28 of the 27C256.  Anything with a red circle is connected.  Can you see a problem ?

[digi2t]

OK, my eyes didn`t make the connection of the two traces on either side of the board. This was early this morning of course, before my first cup of java, so all bets are off.

The Diptrace looks correct though, so we`re back to square one. The important questions here are;

A) If everything is wired correctly, why is position 2 not booting up?
B) Why is XP-200 booting up in position three.

In light of my vero error, I`m going to re-examine my switch wiring scheme as well tonight. Although, I believe that G_L has been using the same schem for several builds now, without issue, so I would be surprised (shocked) if there is an error there.

[Govmnt_Lacky]

Although, I believe that G_L has been using the same schem for several builds now, without issue, so I would be surprised (shocked) if there is an error there.

I have yet to build with the 27C1001 chip, adapter, or wiring scheme 

I am still using my stock of stacked 27C256 chips until they are exhausted so.... I cannot comment on the wiring or correctness of the 27C1001 chip, adapter board, or wiring.

Sorry.. 

[digi2t]

The build doc has been updated, and is now available in the gallery.

The vero has been corrected, and I also added the SRRN pole numbers to the XP-ALL+ wiring diagram. That should clear up any confusion.

I've double checked my XP-ALL+ unit switch wiring versus the document, and all is correct.

[marmaliser]

Dang, that was quick

Just thought I had a breakthrough for a minute, look at the pic



C10 which is in the power section looked a bit bloated and was covered in white powder.  I snipped it off and it measured 11uf which was within tolerance but it needed replacing anyway. 

Sadly after replacement still the same error

Going forward I have a new 27c1001 coming as I have been using 27c010. Not confident but it will rule something else out
Then its replace the adapter with the vero layout
After that its replace the switch
After that its fill the switch hole up and sell it with just the  xp300 rom in it!!

I have had another Xp100 arrive today and this one also has the SMD already and the 256 Chip in a socket.  Bought it for £67 , two days later another one went for £113 ...go figure

Are we sure there are no differences in terms of the mod between these units and the later ones ?

[Govmnt_Lacky]

Are we sure there are no differences in terms of the mod between these units and the later ones ?

The only difference is the headache you save with having to solder in the SMD 574 chip and having to solder in the 28-pin socket for the EEPROM 

The rest of the circuit should function the same as the units with the XP100 code in the CPU submask.

I have modded 3 of the older XP100 units and never had a problem with them. Of course, I did not use the 27C1001 chips but... 

When I mod the "newer" XP100s (the ones without the SMD 574), I dont try to make use of the CPU submask program. I just bypass it and incorporate a 27C256 chip with the 100 program loaded. It is relatively easy to do it this way for me at least.

[marmaliser]

Thats good to know.. Thanks

I must be blessed

[digi2t]

Hey... have you tried erasing your EPROM and reprogramming? Could be corrupted. It's happened to me once, and erasing and reprogramming did the trick.

Or, maybe the EPROM is fubar. Do you do a write verification following programming? I ask because if the switch wiring is correct, then XP-200 should not be booting up in position 3. Logically, it's wrong.