41 replies to this topic

[Beetle]

Quote

Hooking up phi2 properly seems to have improved matters. Now writing values to $D1FF seems to freeze the system fairly reliably.

At least when in BASIC and no Floppyboard connected to BB. Otherwise, nothing happens
Content of D800 doesn't change, however....

[bob1200xl]

Pin 29 of ANTIC is used as ph02 source on the 800XL, pin 39 (not 34) of the CPU is what I used on the 1200XL. Which are you using? Pin 29 will be a little delayed from pin 39.

Does the system freeze when you boot with the BB connected? If not, what is in $0247?

Bob

Beetle, on Fri May 30, 2008 5:50 PM, said:

Quote

Hooking up phi2 properly seems to have improved matters. Now writing values to $D1FF seems to freeze the system fairly reliably.

At least when in BASIC and no Floppyboard connected to BB. Otherwise, nothing happens
Content of D800 doesn't change, however....

[bob1200xl]

Looking at the pictures of the BB...

See those 138 and 139 ICs on the left side? They are the address decoders for $D1FF (and $D800-$DFFF). The 175 is a latch that drives MPD into the PBI. Can you meter the address and data lines from the CPU to these chips? Ph02 will go there as will R/W. One of these decoders sends EXTSEL to the PBI, also. Just label each pin on the chips with where it goes on the CPU. On the 138, inputs are pins 1-6. On the 139, inputs are 1-3 and 13-15. Do you have a logic probe?

Bob

Beetle, on Fri May 30, 2008 5:50 PM, said:

Quote

Hooking up phi2 properly seems to have improved matters. Now writing values to $D1FF seems to freeze the system fairly reliably.

At least when in BASIC and no Floppyboard connected to BB. Otherwise, nothing happens
Content of D800 doesn't change, however....

[Beetle]

bob1200xl, on Sat May 31, 2008 4:17 AM, said:

Pin 29 of ANTIC is used as ph02 source on the 800XL, pin 39 (not 34) of the CPU is what I used on the 1200XL. Which are you using? Pin 29 will be a little delayed from pin 39.

Does the system freeze when you boot with the BB connected? If not, what is in $0247?

Its connected to Pin 39 of Sally.

The system does not freeze when booting with BB connected, $0247 is $00.

Too bad i don't have scope nor logic probe.

[sup8pdct]

Beetle, on Sat May 31, 2008 7:44 PM, said:

bob1200xl, on Sat May 31, 2008 4:17 AM, said:

Pin 29 of ANTIC is used as ph02 source on the 800XL, pin 39 (not 34) of the CPU is what I used on the 1200XL. Which are you using? Pin 29 will be a little delayed from pin 39.

Does the system freeze when you boot with the BB connected? If not, what is in $0247?

Its connected to Pin 39 of Sally.

The system does not freeze when booting with BB connected, $0247 is $00.

Too bad i don't have scope nor logic probe.

Maybe it is time to get your self one:)
My logic probe is part of my multimeter.
There was a mod for the PHi signal sent to the parallel bus.
It involved using O0 and O1 or something like that, and a spare Gate. It stablised the PHi, made it stronger and made it happen slightly earlier.
maybe this will fix the problems.
I have had it time and again when checking things like this, it is easy to miss a small detail.

James

[dmlloyd]

bob1200xl, on Fri May 30, 2008 9:17 PM, said:

Pin 29 of ANTIC is used as ph02 source on the 800XL, pin 39 (not 34) of the CPU is what I used on the 1200XL. Which are you using? Pin 29 will be a little delayed from pin 39.

Hm, that's a thought. Maybe phi2 is too loaded down. Might explain why it works differently depending on what cart is installed and whether the floppy board is attached.

[bob1200xl]

Pin 29 on ANTIC is just pin 39 of the 6502 run through a buffer. This improves the drive capability and delays the signal just a little. The Atari seems to need PH02 skew for some reason. (anybody knopw why?) Try pin 29!

Bob

dmlloyd, on Sat May 31, 2008 6:39 AM, said:

bob1200xl, on Fri May 30, 2008 9:17 PM, said:

Pin 29 of ANTIC is used as ph02 source on the 800XL, pin 39 (not 34) of the CPU is what I used on the 1200XL. Which are you using? Pin 29 will be a little delayed from pin 39.

Hm, that's a thought. Maybe phi2 is too loaded down. Might explain why it works differently depending on what cart is installed and whether the floppy board is attached.

[Beetle]

Quote

Pin 29 on ANTIC is just pin 39 of the 6502 run through a buffer. This improves the
drive capability and delays the signal just a little. The Atari seems to need PH02 skew for some reason.
(anybody know why?) Try pin 29!

I tried it.



YES SIR!!!


PBI Mod to 1200XL was finally a success. Thank you all for helping and brainstorming.
Without your help, i'd still be stuck with a non-working mod.

What we learned:

• PBI pin 40 (refresh line) should go to MMU pin 11, not pin 14
  
• PBI pin 31 (phi2) should be taken from ANTIC pin 29 instead directly from CPU phi2 output pin 39
  
• even a BB can run on 1200XL - if you try hard enough

Now i can take some time to build up the 1250XLD with SCSI HD and HD floppydrives.

Wohooo!

Beetle

[bob1200xl]

Cool...

Keep up the good work!

It looks marvelous!!

Bob

Beetle, on Sat May 31, 2008 2:10 PM, said:

Quote

Pin 29 on ANTIC is just pin 39 of the 6502 run through a buffer. This improves the
drive capability and delays the signal just a little. The Atari seems to need PH02 skew for some reason.
(anybody know why?) Try pin 29!

I tried it.



YES SIR!!!


PBI Mod to 1200XL was finally a success. Thank you all for helping and brainstorming.
Without your help, i'd still be stuck with a non-working mod.

What we learned:

• PBI pin 40 (refresh line) should go to MMU pin 11, not pin 14
  
• PBI pin 31 (phi2) should be taken from ANTIC pin 29 instead directly from CPU phi2 output pin 39
  
• even a BB can run on 1200XL - if you try hard enough

Now i can take some time to build up the 1250XLD with SCSI HD and HD floppydrives.

Wohooo!

Beetle

[Beetle]

Hi

Here i present you some more pictures...



SCSI harddrive in place and 5V powersupply mounted underneath.


As the Blackbox is a large beast, it gets a bit stuffed under the hood.
Of course i tried and measured a lot before deciding everythings place.


If you lift up the hood at the 1250XLDs back, your this view.


Thats what the assembled machine looks with its 'new' 3,5 1.44M and 5,25 360k drives.
Left of the 3.5 drive is the button for BlackBox Menu.


Perhaps this makes the one or other atarian try the 1200XL pbi mod themselves
or fix the one they did in the past.


Greetings,
Beetle

[classics]

Wow

[bf2k+]

You guys simply amaze me! I love this hobby!

[Mathy]

Hello guys and girls

If you come and join us at the Fujiama 2008 on Juli 11th-13nd in Lengenfeld in Germany, you can probably take a close look at Beetle's 1250XLD and his 1500XL.

Check out this page, but be sure to select "English" in the column at the left.

Greetings

Mathy

[Tezz]

Mathy, on Mon Jun 2, 2008 11:29 PM, said:

If you come and join us at the Fujiama 2008 on Juli 11th-13nd in Lengenfeld in Germany, you can probably take a close look at Beetle's 1250XLD and his 1500XL.
Check out this page, but be sure to select "English" in the column at the left.
Greetings Mathy

it's a shame, I would like to have gone to this. I'll be in Germany only late in September so will miss this one. Is anything similar planned in late September early October?

EDIT** sorry, forgot to add.. I've been following this thread. Congratulations on your success Beatle, it was a tricky issue to overcome with the PBI mod.

Edited by Tezz, Mon Jun 2, 2008 5:30 PM.

[retrobits]

I updated the page that Beetle referenced at the beginning of the article to include these corrections.

[Beetle]

Very good. This way other atarians can profit from the work as well.

Thanks,
Beetle

[JellE]

Very nice job Beetle... glad you, dm and the other folks got it all worked out. Keep up the good work!