86C928 GUI Accelerator (202 pages, datasheet/programming)
Lacuna Planar (76/77 i/s)
JMP1 is the Power-On Password jumper. The POP can be cleared by moving the jumper to the other set of pins, then powering on. After power on, you can leave the jumper on the pins that you moved it to.
JMP2 is the Privileged
Access Password jumper.
U15 10G4672 integrates interrupt controller, and drives most of the external I/O - keyboard and mouse, both serial ports, and the parallel port.
VR1 LT1085CT Adjustable Voltage Regulator with max. output current 3.0 A. The regulator is set to 3.56 V and powers the System Controller (U74).
My humble suggestion - DON'T SET THE PAP! If you forget the PAP, only the last saved configuration is valid. You will never be able to successfully change the configuration again. The PAP function involves writing the state to an unknown area of the NVRAM and another memory chip. If the PAP is dorked, for all intents the planar is hosed.
There were several versions of the "Lacuna" board:
Lacuna Riser Cards
Lacuna 76 Riser FRU 68G2706
BT1 CR2032 Battery
Flash BIOS Update Disk
The 7677 FLASH Disk is for the Lacuna planar. Older Model 76 and 77 have the Bermuda planar which does *not* have FLASH BIOS.
Flash BIOS Revisions:
Level 03: Original release
Level 04: Contains the following enhancements:
Level 05: Contains the following enhancements:
Level 07: ?
Level 08: ?
Fixes "IRQ 00 Not Being Serviced" Errors In Error Log
BIOS Revision Notes & Experiences
Can't Access System Partition on 76s (maybe others)
On the 76i / 77i with the Lacuna planar
(and planar IDE, S3-928 SVGA) the "system partition" is
only for convenience - but it is not required for getting
parts of the BIOS into the memory as on the older 76 / 77
with the "Bermuda" planar.
Ed. But they DO support a Convenience Partition IF you use an IBM SCSI adapter (NOT the FD SCSI-2 that is standard). To install a Convenience Partition and be able to access it, you have to LLF the drive and then restore the partition. Just running "Restore System Partition" without LLFing the drive first will result in the system refusing to access the partition. I have a Fast/Wide in my 77s, and I can bring up the Convenience partition with F1. So much better when you have a huge pile of poorly titled or untitled floppies on your desk...
However: I had similar problems getting a system partition on the drive. There had been one once on your drive (the unused 4MB space) but it has been loused up by what reason - same what happened to me. In this case the MBR of this "hidden" partition is invalid and cannot be used any longer. Therefore "Restore system partition" does not work. The only way to get it back is in fact a Low-Level format. In fact the order is important.
You need to install the system partition first, *then* run FDISK from any other operating system. Some FDISKs (like that from OS/2 2.x) do not always accept the "system partition" as hidden ... :-) ... and simply overwrite it or corrupt the boot / MBR information. OS/2 2.1 CID installation was famed for lousing up the system partition on the 76i / 77i.
My recommendation: If you already have a lot stuff on the drive - leave it as it is. If you'd only installed the Win95 so far - mind running the LLFORMAT and install a system partition. You need to start with the reference in A: and press CTRL+A in the main menu to start (A)dvanced Diagnostic. Then run "Format harddisk" and follow the instructions on the screen. Reboot after finish - restart with the reference disk and run "Restore system partition". Worked fine when I tried it last time...
Installing a 5 V CPU
Jumper 3-4, 5-6, 7-8 (pin-9 = key, missing).
Installing an 83 or 63 MHz Pentium Overdrive Processor
Diags Level G7GT55A or higher and interposer required. Jumpers in J19 must be set for a 5 V CPU (the POD has a built in 5 V to 3.45 V regulator)
Installing a 3.45 V CPU
Remove the jumpers. Install VRM.
VRM Connector Pinout
Voltage Regulator Module (VRM) FRU 06H3011, PN 06H3010
The Voltage Regulator Module (VRM), made especially for the 9576/77i system board. It is used to reduce the CPU core voltage from 5.0 V to 3.45 V. That makes it possible to put an Intel 486DX4/100 or AMD 5x86/P75 CPU on the board to upgrade the performance.
VRM Circuit Diagram
(Click on the picture for a hi-res version)
Ed: Tom: The original diagram by J. Shorney had all the input and output pins swapped! This is now corrected (with some other minor adjustments).
Jim Shorney says:
The formula for calculating the resistors is in the regulator datasheet. Use the simpler formula that ignores reference current.
Interposer for POD
Interposer is required to properly support L2 cache on a number of systems. Sometimes, even an interposer isn't enough... 19x19 pin - PGA socket (top-view) Push out the identified pin using a soldering iron. (Ed. Tom: This will completely disable the Write-Back cache mode as described down below.)
Ed. Tom: By removing pin T1 (WB/-WT) you are effectively forcing the processor into the "standard bus" / Write-Through mode (see HERE for more info). So, even if the cache module can be set to WB with this modification, the CPU will operate in WT mode only. I would strongly recommend some proper benchmarking to see what configuration gives better performance.
Note: Some systems do NOT accept ANY (WB) L2 cache modules. I have three Lacunas, none of them supported any of the IBM marked modules or IDT modules. Other people (Bob Watts among others) just seem to drop a POD in their machine, toss in any old L2 module, and it comes up happy. It is NOT the fault of the interposer. Go HERE for details.
Dirty Secrets of the POD (From Peter, edited)
The whole Pentium Overdrive debacle was a mess from the beginning, with Intel changing specs and making motherboard manufacturer's and BIOS writers crazy. (And Louis tried every BIOS level and revision I'm sure.)
In fact they changed the PODP specs shortly before announcement. This L2 communication problem shows up on all these machines where the design work starts in early 1993. At IBM these are namely the PC-300 and the "Lacuna". In a way the PODP was the Edsel of the processors: good idea, bad marketing - and outdated in the right after announcement. Intel hurried it a bit - when the problems showed up the major work was already done for the board-makers.
The main reason for this (AFAIK) is that the original concept did not include boards with L2 WB-cache... the most of the older boards did not have L2 - and if, then it were simple WT-cache. <snip>
Method for Interrupt Sharing with IDE Hard Files in IBM PS/2 Systems
From IBM Technical Disclosure Bulletin (June 1994) (priorart.ip.com)
(Ed.: low-res version here)
Disclosed is a method that allows the interrupt request of an IDE hardfile to be shared with another device (e.g., SCSI hardfile) on interrupt level 14 within an IBM PS/2* system.
The interrupt request (IRQ) of an IDE interface was designed to be on a non-shared interrupt level. According to PS/2 Micro Channel* system architecture, all hardfile IRQs are shared on interrupt level 14. In a Micro Channel computer system that supports both an IDE hardfile and a SCSI hardfile, a problem arises. The essence of the problem is that because the IDE interface IRQ was designed to be non-sharing, no IRQ "indicator bit" exists in any of the IDE status registers. In order for interrupt handling software to determine which of two or more devices sharing an IRQ level is the requesting device, an IRQ "indicator bit" or status bit is needed. The Figure shows a simple solution to provide the IRQ "indicator bit".
To provide the IRQ "indicator bit" for the Micro Channel IDE interface, bit 2 of port 92 was selected. In previous systems bit 2 (port 92) was connected to a pin in the I/O controller chip called SECURITY OVERRIDE. SECURITY OVERRIDE is a signal that can be mechanically jumpered to ground by a customer engineer to override and reset the system password. It sets port 92 bit 2 which is read by POST during system power-up initialization. In normal functional operation, SECURITY OVERRIDE is a static signal tied to +5V. Because SECURITY OVERRIDE will only be jumpered to ground in the unlikely and infrequent case of a customer engineer making a repair to a PS/2 system, bit 2 of port 92 is multiplexed to monitor the IDE IRQ14 line and serve as the needed "indicator bit" as shown in the Figure. The enable for the multiplexer is bit 4 of port E3 which is an output (ROM_PAGE) from the memory controller. During POST initialization, bit 4 of port E3 is set to 0, and the SECURITY OVERRIDE signal is selected and its polarity can be read from bit 2 of port 92. After the necessary testing and initializations have been done, bit 4 in port E3 is set to a 1 before exiting POST. IDE IRQ14 is then selected through the mux shown in the Figure and latched with a free-running clock into bit 2 of port 92. Bit 2 of port 92 then functions as the IDE IRQ "indicator bit".
IDE Hard Drive
I used these to run a WD2540 in 32 bit mode Same as above, Manual installation.
Standard IDE/ESDI HD Controller
Though others have successfully used the Busmaster IDE HD controller. When I set up the 540, it was for an ISA/PCI machine with built-in IDE controller. I was looking for as much compatibility as possible.
Large Hard Drives
From Michael Lybarger:
First I tried to use FDISK, (the latest version, that supports 32 bit), but it would not allow me a partition bigger than 7.23 gig or something like that. I do not know the reason for this. Anyway, the max blast program worked great- I got the whole 10.2 gig (which was the primary reason for going to win98 anyway- 95a does not support a 32 bit FAT). As I said, once I got it set up properly on IRQ 14, It ran in protected mode with the windows driver.
From Ron Doran:
IDE Controller Capabilities
The on-board IDE is a "single channel" IDE but rumors say BIOS 08 is capable to handle drives over 528 MB, mine at home currently runs with a 650 MB, so it is in a way a "half EIDE" interface. Pretty strange.
IDE Planar Header (Where's pin 1?)
Based on personal experience, the IDE header on the Lacuna planar uses a polarized plug. BUT look at the header- it uses TWO keys, one near each end. If you have the common IDE polarized plug on your cable, it has ONE centrally located key....
Luckily, I found a non-polarized plug (no keys at all). All you ISA/PCI veterans know what to do if the system refuses to boot - check the cable pin 1. (I just turned the cable 180, plugged it in, and it booted.)
If you do not have the uncommon dual key plug, simply use a file or a sharp knife and remove the polarizing key off an IDE cable you have laying around. Note that Pin 1 is toward the riser! Look at the planar illustration. The red marked wire goes toward the riser!
From Dr. Jim:
From Martin Adams:
I had the drive set as master, but what ever I did, 3 different cables 3 different IDE CD's. Another planner. Nothing would work. Damn drive door wouldn't even open.
I was looking at the planner and it hit me. I had assumed that pin 1 for the IDE port was on the same end as the FDD cable. I noticed one of the middle pins that was cut for use of a cable the was plugged to act as a key.
I had been hooking up the cable on the planer backwards all the time! So note pin one for the IDE is towards the riser card.
The "Lacuna" board has a 40-pin single-channel IDE controller port just above the FDD-port. It nicely takes harddisks over 524MB if the Flash BIOS release is 08 or 09 (G7GT61A).
The IDE-channel accepts two devices in the usual master / slave configuration on a standard IDE-cable. There is however some care required if you want to use it simultaneously with the SCSI adapter. You need to set the boot-sequence in the "features" properly - to avoid problems when the system tries to boot from an IDE CD-ROM... :-)
IDE CD-ROM on 76/77 i/s
I recently bought an IDE CD-ROM for a 9577 (VTG). I connected it on the motherboard IDE controller. It works correctly under DOS with the following commands:
CONFIG.SYS: DEVICE=BTCDROM.SYS /D:MSCD001 AUTOEXEC.BAT C:\WINDOWS\COMMAND\MSCDEX.EXE /D:MSCD001 /V
But when I try to start Windows 95, everything STOP during initialization of Windows.
IDE CD-R Burner
I have the IDE version of the Model 9576. I want to add an IDE based CD-Reader Writer BUT can't get the reference program to recognize the fact that something is there.
If you don't have a HD on the IDE port: jumper the CD-burner as "Master". The IDE port often dislikes the use of a "Slave only" configuration. And check your systems' BIOS level. Those before 07 had several limitations on the type of supported devices / drive sizes. Take 08 at least.
IDE ZIP + LacunaFrom Bob Watts:
Since the Iomega ZIP drive is an ATAPI compliant device, I was pretty sure it would work, but you never know. I simply plugged it into my IDE cable, and Windows 95 OSR2 found it and installed it instantly with no problem.
For further information, an IDE CD-ROM device was previously on this cable, and it is jumpered as Master, and the ZIP drive is jumpered as Slave. Also, an IBM 0662 1 gig SCSI drive is the boot drive, on the factory installed Future Domain controller.
S3 928 Video Drivers
S3 and Diamond merged, lookit HERE.
2. The S3-928 cannot be disabled physically. It goes in some sort of "sleep mode" when another VGA / SVGA capable card is detected - nonetheless parts of the card is still activated and *may* cause trouble.
Not confirmed: the early BIOS releases below 07 seem to be more vulnerable to video disturbances with S3 and other video cards. One thing IBM tried to fix with 07. In either case you better use a BIOS 08 - also for the "over 524MB HD" capability.
3. The XGA-2 card has not been announced to be used with the "Lacuna" series anyway. IBM seems to have removed the card from the list, because in the first announcement of the 76i / 77i the XGA-2 is still listed - not in the later product / option matrices and product descriptions on the "Lacuna".
4. The 9515 and 9517 monitors are not 800 x 600 capable *per IBM*. They can be tweaked to show an 800 x 600 like picture, but it is distorted and the monitors have no explicit mode for it. These screens are "XGA-2 only" Multi-Mode screens with fixed adjusted presets. They are no Multisyncs.
If you want to run the Lacuna with most of the possible modes switch to a 9525 or 9527 monitor. Or any other good SVGA screen. I run my "workhorse" 9595-S30 with XGA-2 on an Eizo F35, the 9577-BTG runs with a NEC 15XE and both do fine.
5. Nonetheless the XGA-2 (at least) will run in a Lacuna. There might be some interference to clear out manually during OS installs, which is the primary video system. This is usually the one with the monitor attached. In 99% of all cases OS'es get that right - but sometimes the on-board video is ranked higher and the OS gets confused. (Haven't seen that too often to be true - but can happen).
800x640x64k under W95
The onboard-video chipset is a S3-928 SVGA. The box runs nicely with Win 95 - will most likely also run nice with Win98, since it has IDE and not IBM MCA SCSI (which is only merely supported with 98). To install the appropriate drivers for DOS/Win 3.x / Win95 see the "W95 Setup for S3 SVGA" setup page. This will enable your machine to use the full potential of the S3 chipset.
Display adapter cards that use the Auxiliary Video Extension when installed in a system require installation in slot one (9576) or slot two (9577) and attachment of a display to the system video connector during configuration of the system.
Video Adapters under W95
There is no way I know of disabling the on-board video. W95 says there is a conflict, but none shows up under Device Mangler. You cannot successfully configure the add-in video card.
Lacuna Video Glitch
> I have a 77s that has displayed a charming quirk- it waves the top half inch of the screen. Not all the time, but...
Please check the type of the Video RAMDAC - and the origin of the S3 chip. Some Thailand-S3s have internal bugs using an earlier stepping mask. The RamDac should be the AT&T in this case. These were the machines that cause massive faults under OS/2 2.1...
The S3 chips are famed for a lot "undocumented features" (like using an address for COM4 (? yes - think so)) and this chipset is -basically- a VESA Local Bus chipset which is stitched in the Lacuna planar with a hot needle.
> IIRC, the last three digits of one of the S3's I/O ports is 2e8. Like B2e8h or something
Yep. That was it.
> If I understand this correctly, it wasn't S3's fault that some com port hardware did faulty address decoding.
Yes and No. On MCA it wouldn't have been too bad, because MCA *should* use a full decoding (or: 24 bits at least, 16 bit for the I/O range), but -again- the VLB chipset was a little buggy already, before IBM decided to put that on a MCA platform. Who's to blame ? S3 -in addition- delivered chipsets which were out of specs for some series which made things worse than it already was.
> The workaround was to not use com4/2e8 if possible, or to remap com4 to a different address if it was really needed.
IBM's COM3 - 4 ports on the PS/2 were not "XT-style" so this COM/Video interference wasn't much of a problem here. It was *much* worse on the "Rocket" PS/VP Series 3, which were PCI/ISA with more generic layout and addresses. They used S3 chipsets too...
> I have seen Lacunas with S3-928 Rev. G and Rev. P. Seen both kind with either a BT or AT&T DAC also.
Most likely the -G- revisions are afflicted by what IBM euphemistically called "video timing glitch"... which cause the entire machine to crash under OS/2. IBM offered various bug-fixes for OS/2 2.1 and tried to fix the problem with modified hardware as well, which lead to slight incompatibilities with driver versions. The drivers for the original (un-fixed) 2.1 did not work very well with these machines. The APARs offered for Germany were... now... not so good. The US-APARs seem to be better, but you should not mix different language versions within any OS. The later series of the "Lacuna" seemed to be more stable and especially with OS/2 Warp the problems rarely occurred.
Some machines that have been migrated to Win95 show up odd effects recently. Especially when switching to and from DOS-boxes into full-screen hi-res modes may cause the system to hang, fall into GPF or show odd colored icons / missing icons / speckled screen etc. This seems to be caused by a faulty, out-of-time palette read... haven't noticed that on my machine, so I guess the -P- level of the S3 seems to be stabilized.
Mediaburst Module FRU 71G5839
MediaBurst Movie Adapter expands up to four times the window size of many software motion-video compression algorithms, such as Video for Windows or Ultimotion(TM), and provides access to the VESA Media Channel (VMC)
The MediaBurst Movie device driver uses the PowerPlay 32 video accelerator chip to provide enhanced playback of digital video. This allows viewing of video clips in larger-sized windows or full-screen without the degradation in speed and picture quality usually associated with software motion video.
Key features of the MediaBurst Movie option include:
Resolution Supported By Mediaburst Option:
Graphics AVI File Video Smooth Mode Colors Format Acceleration Scaling --------------------------------------------------- 16 ALL No No 256 8-bit Yes No palletized 256 All Others No No 64K All Yes Yes 16M All No No
My thanks to Brad Parker for ripping apart his 77s and sending me a scan.
Does the 77i even support ECP? My printer/CD/ZIP drive doesn't work...
Do the following:
That should fix the problem. The 9577 -as most PS/2- has a "DMA-arbitrated" LPT-port, which is neither ECP nor EPP, only "sort of". The "Disable" directs the machine not to use DMA during bi-directional transfers and use a contiguous data-stream.
The DMA-mode tends to miss returning signals from PP-devices especially PP CD-ROMs, Tapes and Zip-Drives. Some printer-drivers use the bi-directional communication to signal details from the printer back to the computer.
Direct Connection under W95
Yes it does work. I even used the ECP port setting with the parallel cable. Both ports were at Parallel 2, and DMA Arbitration 1.
Parallel Port "!" under W95 with Audiovation
I was thinking way too hard on this. The default choice for W95 to assign an IO Range for a MCA parallel port is 3BC-3BE. BUT this conflicts with the first memory range of the S3 928 (check resources, the first range is 3B00-3BFF). Set your parallel port to "parallel 2" under system programs, which is the standard 378-37D address. Then under W9x, set the IO range to 378-37A. "!" goes away.
Overclocking the Lacuna boardFrom Zp Gu:
This mod is relatively easy. I changed the 66.667 MHz Osc to an 80 MHz surface mount crystal osc. from Digikey and the board is now running an AMD-133 at 160 MHz without any problem.
The board actually has 4 thru-holes under the Osc, but IBM chose to put an SMD instead of a half size socket. Socket would have made life much easier. I didn't attempt to put a socket there since I don't have the right equipment/skill to do so. I just soldered a surface mount 80 MHz to its place.
Putting a POD83 in failed POST. I can't imagine Intel being so tight on this, but maybe it's just my bad luck. Running it at 83 MHz was no problem.
From Peter Wendt:
The effect was much worse with the Kingston Turbochip - but also noticeable with the original DX4-100... where in addition the VRM turned really hot ! Significantly hotter than under normal operation - a sign that the power drawn from the DX4 at 40 MHz is "a little bit" higher than at 33 MHz.
I had only a "full size" oscillator and needed to build a sort of "adapter" from half-size holes to full-size socket. But that's a minor problem. *Then* I needed to solder an adapter for the original 66.6667 MHz SMD-crystal... Aaak!
Anyone tried that modification with a "Bermuda" ? These have MCA XGA-2 cards and no "local bus video" as the "Lacuna". Should work a bit better there... probably.
From Zp Gu:
From Peter Wendt:
Early Lacuna Streaming Limitations (source)
LanStreamer and EtherStreamer adapter don't work in 76i/77i with 25 MHz planar (FRU P/N 95G9691).
Streaming mode adapter cards are not supported for use with 76i/77i systems fitted with 25 MHz planar. The problem is caused by a limitation of the level of Bus Interface Controller chip used on this planar. Replace the systemboard FRU P/N 95G9691 with FRU P/N 96G1305. (Identification - 95G9691 = 'yellow' / 96G1305 = 'blue' "SynchroStream Controller".)
The 25 MHz boards are afflicted by a flaw in the "SynchroStream Controller": a large yellow or blue chip somewhere in the middle of the board. If yours is P/N 95G9691 and has the yellow SynchroStream Controller it might not work with the faster network adapters of the IBM Streamer series. If it is P/N 96G1305 and has the blue SynchroStream Controller it is not afflicted by this misbehaviour. In "normal life" this has no affect however - you only will take notice if you use adapters that use the 80 MB/s high speed data streaming.