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Difference between IDE controller on 1997 beige G3 and 1998 beige G3

powermax

Well-known member
IDE support in Beige G3 is provided by the Heathrow ASIC. The Desktop variant, ROM Release 0x40F2, uses REV 1 of the Heathrow ASIC.
That's what the device tree node in OpenFirmware 2.0f1 displays for Heathrow:
Heathrow node.png


Please notice the value of the `revision-id` property that contains "1".

Now someone that owns a Rev C board is asked to check the revision number of the Heathrow ASIC.
If it's still "1" than the issue must be in the system software, precisely speaking the ATA Manager.

BTW, please keep in mind that IDE aka ATA is considered a mess before 1998. Even if there were attempts to standardize this (mildly speaking) HW hack there were a lot of manufacturers that didn't follow the standards. Unfortunately, that's also true for Apple whose IDE controller cells use different PIO timings as recommended in the specs...
 
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Phipli

Well-known member
IDE support in Beige G3 is provided by the Heathrow ASIC. The Desktop variant, ROM Release 0x40F2, uses REV 1 of the Heathrow ASIC.
That's what the device tree node in OpenFirmware 2.0f1 displays for Heathrow:
View attachment 43119


Please notice the value of the `revision-id` property that contains "1".

Now someone that owns a Rev C board is asked to check the revision number of the Heathrow ASIC.
If it's still "1" than the issue must be in the system software, precisely speaking the ATA Manager.

BTW, please keep in mind that IDE aka ATA is considered a mess before 1998. Even if there were attempts to standardize this (mildly speaking) HW hack there were a lot of manufacturers that didn't follow the standards. Unfortunately, that's also true for Apple whose IDE controller cells use different PIO timings as recommended in the specs...
Not exactly what you said, but for reference, this is a Rev B board.

Are we certain there were rev C boards? My Late Rage Pro board is a B too. That had the latest ROM in it.
 

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Phipli

Well-known member
Not exactly what you said, but for reference, this is a Rev B board.

Are we certain there were rev C boards? My Late Rage Pro board is a B too. That had the latest ROM in it.
Interesting though, OpenFirmware is 2.4 on mine, vs. 2.0f1 on yours.
 

Phipli

Well-known member
@Phipli Thank you for the device tree dump for your board. Judging by the revision-id property, it's still the same IDE hardware.
Yes I saw. Matches what I thought I remembered. Newer ROMs fix older machines.

We need to flash a batch of Rev C (or Rev 3, whatever they are) ROMs.
 

powermax

Well-known member
We need to flash a batch of Rev C (or Rev 3, whatever they are) ROMs.
Do we need new ROM SIMMs for that or is it possible to reflash old ones?
BTW, I remember seeing a Wiki page with pinouts for various PowerMac ROM SIMMs.
It looks like the page has disappeared. I can't find it anymore.
IIRC, it was created by @trag but I'm not sure...
 

demik

Well-known member
Rev 1 also here :

Code:
00:10.0 Unassigned class [ff00]: Apple Inc. Heathrow Mac I/O (rev 01)
    Flags: bus master, medium devsel, latency 32, IRQ 21
    Memory at f3000000 (32-bit, non-prefetchable) [size=512K]
    Kernel driver in use: macio
 

NJRoadfan

Well-known member
ROM Revision: $77D.45F2

Open Firmware information for Heathrow is exactly the same as @Phipli

Note that the ATA implimentation on the Beige G3 was pretty funky at the ROM level. The machine suffered from the same Int 13h 8.4GB boot barrier despite that problem being specific to the PC BIOS! Also, I think MacOS X's native drivers will enable the use of slave devices since the buggy Rev A ROM is no longer controlling I/O.
 

trag

Well-known member
Do we need new ROM SIMMs for that or is it possible to reflash old ones?
BTW, I remember seeing a Wiki page with pinouts for various PowerMac ROM SIMMs.
It looks like the page has disappeared. I can't find it anymore.
IIRC, it was created by @trag but I'm not sure...

Hmmm. Where did the Wiki go? Doesn't seem to be a link to it at the Home 68kmla.org page. That's where the pinouts were listed.

https://www.prismnet.com/~trag/Apple_pinouts/Firmware_Module_Pinout.txt

And https://www.prismnet.com/~trag/Apple_pinouts/

For some other Apple pinouts I did.

Note those are going to move by October, as prismnet.com is shutting down.

Also, interesting to note that you can find the pinout in the original Power Macintosh Hardware Developer Note.

The NuBus Power Macs use the same ROM module as the PCI Macs and the Beige G3 (Beige has different Vcc pins). And the NuBus PMs used the exact same slot configuration for the Cache and the ROM module. So if you go to the Hardware developer PDF for the NuBus PMs and look at the provided pinout for the Cache slot you'll get an almost complete listing for the Beige G3 ROM slot.

Little things are missing, of course, like the one pin you can bias on the Beige ROM which kills RAM support above 512MB...

Finally, I can make some more Rev. C ROMs (or Rev. B, I think) if anyone wants them. Or maybe send kits to solder. Not much spare time these past many months.

Circuit board, 14 resistors, 5 capacitors, 4 programmed HY29F800 chips. Not sure where I'll find time to program chips...
 

powermax

Well-known member
@trag Thank you for reposting the link to your ROM pinouts.👍

AFAIK, pin 122 of the Beige ROM DIMM tells whether 64bit burst access ROM is installed. "0" (low) means burst ROM is present...
 
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Trash80toHP_Mini

NIGHT STALKER
Again, don't think there was ever a Rev.C beige board, those would be the revised beige boards that happen to have been equipped with the Rev.C ROM when built. Can anyone confirm this?
 

Trash80toHP_Mini

NIGHT STALKER
I have three Rev B logic boards, but two came with Rev A ROMs, at least one of which is likely to be original. When finding the board you want, look at the video chips, you want one with a Rage II Pro Turbo - there is a mix of Rage II types used on beige G3s.
Just remembered that tidbit. Was there a third variant or was Rage II Pro Turbo used across all the enhanced BG3 logic boards?
 

Phipli

Well-known member
Again, don't think there was ever a Rev.C beige board, those would be the revised beige boards that happen to have been equipped with the Rev.C ROM when built. Can anyone confirm this?

My 300MHz desktop is from a month before they stopped making them, Rev C ROM, Rev B board. Has the Pro Turbo, other two don't, but are earlier in 1998 (10th and 15th weeks).
 

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CC_333

Well-known member
So there are Rev. B boards with Rev. C ROMs and a graphics chip which was allegedly installed only on Rev. C boards?

Fascinating!

I have a 333 MHz Beige G3 (probably making it one of the last (A S/N check could probably confirm this), and thus the likeliest to have a Rev. C board), but what Rev it originally was is now unknowable because I hastily sold the logic board out of it to fulfill a deal for a G3 AIO board I had originally promised to someone, but couldn't find. The G3 tower's board was the only one I had access to at the time, so that's the one that went, with the plan being that I would reassemble it using the G3 AIO board once I found it (I eventually did). As a result, this means it's probably a Rev. A or Rev. B now (did AIOs ever receive Rev. C boards from the factory?).

I do, however, have another AIO and a G3 DT with presumably original boards that I could check, if only because I'm curious at this point (if the DT has a Rev. A board, that might explain why I was having problems getting it to properly recognize hard drives when I tried fixing it up — 8 years ago — because maybe I didn't understand its limitations and tried things that nomally work on other machines, but break on Rev. A boards).

c
 
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CC_333

Well-known member
Well, I blew my most promising chance to contribute an answer to that question. See my last post for the reason why.

I have three more chances, but they're most likely not Rev. C's. Again, see my last post for more details....

c
 

Trash80toHP_Mini

NIGHT STALKER
I see specific differences between first release and the enhanced model. However any further changes appear to to me to be component compatible builds to upgrade performance of what's called Rev.B. There are A/B/C ROMS with the latter likely required for making full use of the Rage II Pro Turbo, which I'm guessing is the same package as the more pedestrian variant on earlier Rev.B logic boards that are identical to what some are calling a Rev.C board?

No note of a third variant of the system board mentioned on everymac, just component upgrades?
 
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