#GVPserII/2386BB-help!
33 messages in this thread
In need of some help…I recently purchased a new 2386 SX 25 mhz
Bridgeboard. I hooked it up using a Bernoulli HDrive and ICD controller. It
worked well..I set up a quantum drive for the PC etc… I then a new GVP
series II board with 8 meg ram, using the same HDrive and what should
happen ..now access to the BB as it could open up Janus library SO I hooked
up a conner internal drive …fornatted under 2.0 etc and once again die
the PC installation ….the same thing. I put the icd board back in and
left the gvp in just for the memory (no drive) it still could not find the
Janus Library…..I took out the gvp and presto….the gvp rom is version
4.5
anyone had this problem?? DA
I just made another discovery…if I disable the ram via the jumpers on the
gvp board the BB will work as soon as they are enabled no go. any
solutions? DA
Don…
The Bridgeboard takes up some of the autoconfigure RAM on the Amiga side,
so you can't use a full 8 megs added RAM.
It's interesting that your board works with the RAM disabled–other people
have told me they actually had to remove the chips.
Marion
CROSSINGS
Newsletter for The Brideboard, etc.
Marion,
If you are handy with tools you can do what I did. I ran a
connector from the board jumpers which are used to set the amount of
onboard ram to a toggle switch mounted on the back of the case. That way I
can toggle how much of the board's ram is running. Of course if you change
the switch setting you will need to reboot.
Steven,
Could you send me a diagram of how you did that? A couple of people have
done it, but I've never been able to get a diagram I can print.
Marion
CROSSINGS
Newsletter for the Bridgeboard, etc.
Marion,
It's really difficult to do that because various memory boards
likely use different jumper combinations. For instance, on my old
Microbotics 8UP board there was only one jumper needed to enable/disable a
2 meg bank. So it was easy to simpy run two wires from the jumper pins to
a SPST toggle switch. But on my Nexus there are two jumpers involved, so I
had to run 4 wires from the jumper pins to a DPST toggle switch. Thus, the
mechanism required is very product dependent, but the concept is basically
simple:
o———o o
o———o/
| jumpwe | SPST switch
When the switch is open the jumper is open and when the switch is closed
the jumper is shorted. The memory is enabled/disabled depending upon
whether the jumper is shorted or opened. If more than one jumper must be
controlled, then you either add another switch (the hard way) or get a
multi-pole switch. If you need to control two jumpers, then a DPST switch
will do the trick with both poles wired the same as above. Of course, this
can get complicated if the board requires shorting one jumper while opening
another! As you can see there isn't ONE neat solution.
Steven,
Thanks for the info about switching out the memory. I see what you mean
about it being product-dependent. But even if I cover one product at a
time, some info is better than none.
Marion
CROSSINGS
Newsletter for the Bridgeboard, etc.
True, so feel free to put in what you'd like. This is pretty simple stuff
and I doubt it's covered by any trademarks, copyrights, or patents!!
Don,
I don't use a bridgeboard, but I seem to remember that the BB takes up
2MB of the expansion memory map(?) and so you must limit the memory
expansion on your Series II card to 6MB.
Try reconfiguring the jumpers on it. There should be instructions in the
manual of the GVP card for BB setup.
Chris
Chris,
BB's take up 512K, but most memory boards only allow 2 Meg
increments, so that's why you have to remove that much.
Don
Thanks Don,
So it might be a safe bet that there is a conflict with the 8MB of ram on
the GVP Series II controller and the BB? Also, that reconfiguring it as a
6MB memeory space might solve his problem?
BTW, do the other memory boards that allow an A2000 user to go beyond the
8MB limit (like the GVP Combo boards 16MB) co-exist with Brideboards?
Chris
Chris,
The BBs must have part of the autoconfig memory space for the Janus
interface, thus you generally cannot have more than 6.5 meg of fast ram in
the normal address space. It's possible that if the 32 bit memory can be
allocated outside of this space then the BB might work, although I haven't
had the facility to test this. My GVP card cannot place its memory above
the normal autoconfig space. I did have a Hurricane 68020 card which used
an Addmem program to install its 32 bit ram and could install the memory
above the normal address space, but when I once tried it the BB still
wouldn't work. That might, however, have been specific to the Hurricane,
which was an old accelerator dating back to the earliest days of the A2000.
Steven, That's 7.5 megs of autoconfig ram, not 6.5 megs. My machine has
7 megs of autoconfig ram with an ATBB – 4 megs on the 2620 board, 3 megs
on a Microbotics 8up! board as two banks, one with 2 megs, other with 1
meg.
73, Kelly
Kelly,
According to Don Curtis, you only have to have a 512K address space for
the BB, but most memory cards only allow increments of 2MB, apparently
your 8up! board allows memory in increments of 1MB. So yours is the better
memory solution.
Chris
Chris,
The 8up! board allows for the following different memory sizes:
– 512k
– 1M
– 1.5M
– 2M
– 2.5M
– 3M
– 4M
– 4.5M
– 5M
– 6M
– 8M
I am using the 3M configuration. The board acts like two memory boards.
Two device sizes can be used, 256kx8 and 1Mx8. You can use the same
device size on the whole board, or have one half of the board use 256kx8
size and the other side use the 1Mx8 size. For the 3M, one side uses four
256k devices, the other side uses two 1M devices.
If I changed my SCSI interface from the 2090A to something like the 2091
which has room for memory (now was that 1 meg or 2???), I could configure
the 8up! to 2.5M (or 1.5M if the 2091 has room for 2M) and have a full 7.5
meg of autoconfig ram.
My system has 7 megs of autoconfig ram and, thanks to DKB, 2 megs of chip
ram, for a total of 9 megs. Never enough memory, especially when running
AVT_Master and ImageMaster and want to still do other things!
73, Kelly
Kelly,
Sounds like that 8up! board is just the ticket for a bridgeboard user.
Chris
Kelly,
I guess if it works it works. According to the documentation,
however, it specifies 6.5 meg, or at least that's what I seem to recall. I
remember that somewhere I had read that Janus needed 2.0 meg of address
space. I know that I have had reasonable success with 6.5 meg of fast ram,
but not with 8 meg. I never had tried it with 7 meg. Maybe I'll disable 1
meg of ram on my Nexus controller card and see if it will run with 7 meg.
Maybe someone here can provide the "definitive" statement on this.
Steven,
No…BB's only require 512K of address space, but since most of the
original memory cards only had 2 Meg increments…you had to remove a full
2 Meg to get the BB to work. If you have a 7.5 Meg board, the BB will work
fine.
Don
Don,
Well, do I understand you to say that BB will work regardless of
the memory installed, or only in the bottom 8 meg, which is what I think
you mean and I understand. I can't test that out, however, because my
memory board can only disable memory in 2 meg increments. I checked that
out last night. Then what's this bit I remember from awhile back when the
first BB came out that required a large chunk of auto config space? I
definitely recall this from awhile ago in either AmigaWorld or Amazing.
However, for me it's academic. I have 4 meg of 32 bit ram on the
accelerator and 4 meg on the Nexus. I can't disable the 32 bit ram except
in 4 meg chunks, and the Nexus only allows 2 meg chunks. So it's either 8
meg or 6 meg!
Steve,
Yes, there were (perhaps still are) some memory boards out there
that allow 7.5 Meg of added RAM…they were designed that way with the BB
in mind. All BB's have worked under that. I forget what AmigaWorld or
Amazing said, but if they said that it required 2 Meg of autoconfig
space..they were wrong.
What I recall the old articles saying was that most memory boards
only came in 2 Meg increments…so you had to remove 2 Meg to get the BB to
work. And that part is correct.
Don
Steven,
When boards go through the autoconfig process, the system asks how much
room they need. Usually, non-memory boards, such as SCSI interfaces,
graphic boards, serial boards, etc require 64k bytes or less of system
memory space, so these boards are given a memory slot outside of the 8
megabyte memory range allocated for memory boards.
The BB needs more than 64k bytes of system space, so it could not be
assigned a slot outside of the 8 megabyte memory range. Since the BB can
not be allocated space in th IO slots, it must be given a slot in the
autoconfig memory area. The smallest slot that can be allocated in the
autoconfig memory area is 512K bytes, thus the BB uses up 512K bytes of
the 8M memory space. Clear? (like mud)
The BB actually occupies 512k bytes of memory space, but this is more to
do with poor design than anything else.
73, Kelly
p.s. 8 Megs – 512k = 7.5 Megs!
Kelly,
No, in fact it's very clear. I seem to remember in an article
about the first BBs that they actually used much more of the autoconfig
space and consequently limited the expansion ram to 6 meg. However, your
explanation is quite clear regarding the 512k requirement. I understood,
however, that the memory requirement was needed for the shadowed ram that
the Janus interface shared with the Amiga, but perhaps I misunderstand
that.
Can some one discuss how these memory requirements (for the dual port ram
required for BB use) affect the A3000, which can auto-config more than
8meg?
Michael,
The Bridgeboard is a Zorro II device. Zorro-II is limited to 24-bits
of address space, which means that the only addresses it knows are within
the lower 16-megs of address space. There are 8 megs of "fast" memory
addresses available in the 16-meg space, and the Bridge's dual port ram
must be assigned from this pool.
Zorro-III memory (and other Z-III cards) has the full 32-bit memory
addressing ability available. Also, the "fast" memory on the 3000's (and
4000's) motherboard is addressed above the 16-meg limit (addresses start
at hex 01000000, where the 24-bit addresses range from hex 00000000
through 00ffffff).
Hope this helps….
– BobR
Kelly,
It's not a bad design, the 128K of dual port RAM on the BB
configures at 4 separate addresses (thus 512K) in the Amiga's memory map.
The reason for the 4 different addresses is due to the way that dual port
RAM is used. I've got the exact information in my notes…but my memory
says that the reason they need to 4 different addresses is that's easier
for the Amiga to do all the conversion necessary to convert the display or
pump data back and forth than it is to get the MS-DOS side to do it. Thus,
the MS-DOS side simply sees it as one 128K address and writes to it as it
would any other interface memory (between 640K and 1 Meg). The Amiga does
the "work" involved, and determines what work to do based on which of those
4 windows is being addressed.
Don
Chris,
yes…it's a very safe bet that having 8 Meg of RAM (excluding
something like the extra Meg you get with DKB's MegaChip board) will
prevent a BB from booting.
No idea on boards that go beyond the 8 Meg limit…I presume it
would deal with how they implement it…thatis, do they backfill the 8 Meg
memory space first…or is it done otherwise?
Don
Chris: Some acellerators and models of Amiga (3000) map their 32-bit
memory above the normal 16-bit memory space for the 500/2000's. Thats why
I can use a Bridgeboard without removing any 32-bit ram. But if I decided
to add 16-bit memory then I could only put in 6 megs if I wanted to use
the BridgeBoard.
John – K7KB (Flying via AutoPilot)
Problem solved …thanks for the soloution…I was starting to go out of my
mind…..What would happen if I increase the ram on the BB to a full 8 meg?
DA
Don,
You can put all the ram you want on the BB, it makes no difference to the
Amiga side of the system. The 512k slot in the Amiga memory map taken up
by the BB is due to the way the two systems talk to each other thru an
additional chunk of memory not part of the BB's program ram.
73, Kelly
Glad to be of help, indirectly anyway <grin>. You shouldn't have any
memory conflicts by adding the 8 megs to the BridgeBoard.
John – K7KB (Flying via AutoPilot)
Don,
The only memory that is shared between the sides is the 128K of
dual ported memory on the BridgeBoard. The Amiga needs that 128K
configured at 4 different addresses and thus needs 512K of "space" in it's
memory map. But beyond that, there is no sharing of memory. So no matter
how much memory you have on the BB, it won't make any difference to the
Amiga side. That 128K of dual port memory on the BB configures as part of
the ROM space allowed under MS-DOS, not as User RAM (ram in the lower 640k
or above 1 Meg under MS-DOS).
Don
Don,
You've got too much memory in your system, thus there's no where
for hte BridgeBoard to "configure". You'll have to remove at least 512K of
memory from the board IF THE BOARD CAN BE CONFIGURED AS A 7.5 MEG BOARD,
otherwise you'll have to remove an "increment", whatever that may be on
your board…normally 2 Meg.
Don
Your problem is quite simple. You cannot have more than 6.5 meg of fast
ram when the BB is operating. You need to disable some of the GVP memory
or, if GVP permits, allocate the GVP ram above the normal Amiga autoconfig
address space.