GVP G-Force 030 How to Boot in 68k mode?

[ahandyman59]

I have a Great Valley Products G-Force 030 (Impact A2000-030 Combo Series II) installed in an A2000. That's one of these: http://amiga.resource.cx/exp/gforce2030
Rev 4. My particular one has SIMMS, not 3 with one set of chips soldered to the board, like in these examples. Other than that they seem to be identical.
My question is how to you get this to boot in 68k mode, rather than 030 mode? Other threads mention a jumper 11. There is no jumper 11 on this board! Other threads say hold down the right mouse key while booting, then hold down the left mouse key while booting, and lastly hold down both mouse keys while booting. None of these cause the a2000 to boot in 68k mode. Both mouse keys bring up a menu that lets you choose pal/ntsc and which drives are active. There is a Disable CPU caches, but none of these force 68k mode on boot.

Yes there is software to switch it on or off, but that won't help with NDOS type disks.

What's the secret to forcing these to boot in 68k mode?

Thanks again for the help. This is a great forum!
Ahandyman59

[emufan]

using the shell/cli tool: GVPcpuCtrl Boot68000
is on those disks in your link.
not tested but i found that info in a gvp manual on bombjack's website.

[thebajaguy]

GVPCPUCTRL Boot68000 from a suitable GVP 68030/68040-product floppy will do it (one time). There is also a hardware jumper on all products to keep the accelerator card disabled. Look for a J2 (matches the Rev 3) to disable. The boards were built with the first bank able to be soldered on (cheaper, production test streamline, and socket also less likely to be damaged), or take GVP SIMM32's.

[mark_k]

Also, older GVP disks had a Boot68000 program which I seem to remember worked for my board where GvpCpuCtrl BOOT68000 didn't. I hacked up a simple check for the left mouse button (so the program would exit if not pressed) and put it in my HD startup-sequence.

Attached here if anyone's wants to try it.

[thebajaguy]

[QUOTE=mark_k;1150751]Also, older GVP disks had a Boot68000 program which I seem to remember worked for my board where GvpCpuCtrl BOOT68000 didn't.

What model/rev board do you have? By any chance is it one of the 22/33Mhz low-cost 68EC030 models?

[mark_k]

The 22/33MHz boards have a full 68030, or at least mine does. Mine is the 68030 with 4MB on-board RAM.

It looks the same as the one shown at http://amiga.resource.cx/exp/combo. Not sure whether my board is rev 3 or 4 though.

[ahandyman59]

Removing J2 appears to disable the entire card, not just the accelerator cpu. The SCSI connection is dropped too. I didn't check the RAM, but suspect the RAM has been disabled too. Again, I a looking for some kind of hardware solution, because of booting with NDOS disks.

Maybe a switch on the J2 jumper is the only way, and I'll have to deal with the good and the bad of it...

[mark_k]

Yes it's all or nothing, you can't use the on-board SCSI or RAM in 68000 mode.

[Irl]

Just wanted to chime in.. I have a GVP Combo 030 25mhz. The program to switch to 68000 mode works like a charm on my system, and there isn't anything that should prevent it from working for you.

When the App is run, it reboots the system and should boot up in 68000 mode. When booting 68000 mode, I usually am attempting to run a game from a disk, so I have never tried to use the SCSI drives to know if they are disabled with software fall-back. I can confirm they are 100% disabled when you use the jumper. The jumper will disabled the entire card and your system will boot with the 68K on the motherboard.

The very next reboot (warm or cold) will re-enable the 68030.

The 'hold mouse button' methods require special commands in your startup sequence that will detect the mouse button and react accordingly (by running the application to force 68000 fall-back). I do not know these commands off-hand, but this was mentioned in one of the manuals or maybe it was an Amiga Guide file on the disk... idr.

My A2000 is using Kickstart 3.x, but the 68000 fallback application should run on (iirc) 2.0+

[Irl]

There are a few utilities that can check the mouse button in startup sequence. You can place a command to run the 68000 fall back program if mouse is pressed down. Then, you would boot with left mouse held, the system would start to boot, reboot, and should be in 68K mode after.

From: https://groups.google.com/forum/#!to...er/FrMNPXI6Cz4

Here's a little assembley program to check the Left Mouse button. It simply
sets the return code to 5 on exit if button down.
In your startup-sequence or other simply call this program and act on the
result. It should not be to hard to add the right mouse button as well.
Here is a script I use

CheckLMB ;program below
if warn
execute s:startup-sequence2
endcli
endif
execute s:startup-sequence1
endcli

*** Program to test left mouse button ***

btst #6,($BFE001).l
beq.b .buttondown
moveq #0,d0
rts
.buttondown
moveq #5,d0
rts
--
*** John Veldthuis, Taranaki Amiga Users Group, jo...@tower.actrix.gen.nz ***

[ahandyman59]

The version I have is a 40mhz 68EC030. it is indeed running at 40mhz.

Again, the intent is to make the system run in 68k mode so that disks set up with NDOS disks don't get accelerated.

That program to run in fallback mode with a mouse click is interesting, but doesn't that only work when the hard drive is accessed? If the computer is booted from a floppy, it cannot load a hard drive to load that program and test for mouse click, can it?

Is there no way except for turning the entire card off (jumper 2)?

[thebajaguy]

The J2 disable affects the entire card.<br />
<br />
Locating another controller in a Zorro slot is the only other option in fallback mode to have more than a floppy boot. <br />
<br />
I actually run a GVP HC8 with 6MB and a Spectrum 28/24, and map the accelerator 32-bit RAM in the &gt;16MB setting. I have run disks (er, SCSI to flash media modules) on both interfaces.

[Irl]

Originally Posted by ahandyman59

That program to run in fallback mode with a mouse click is interesting, but doesn't that only work when the hard drive is accessed? If the computer is booted from a floppy, it cannot load a hard drive to load that program and test for mouse click, can it?

The usage here would be to have the floppy disk ready and boot the system from HDD with mouse button held. It will execute fallback tool and reboot system. At this point you would insert the floppy to boot from.

AFAIK the tool is the only way to switch to 68K w/o using the jumper to disable the card. You should be able to boot normally into Workbench, insert NDOS disk and run the tool from it's icon. The system should reboot into 68K mode and boot the floppy disk.

Edit: The tool will send a command to the card to enable the fallback mode and reboot. This setting is stored in some non-persistent memory, meaning it is cleared if the system is powered off. This is why it is possible to access the tool from an HDD and then lose access to the HDD for the rest of your fallback-mode session.

Edit 2: The manual makes it sound like the mouse button switch is built-in, but I have tried it several times and it will not work. That is why I suggested using a tool, called from startup-sequence, to do the same function. I am going to try to get this running on my system as it is faster.

Edit 3: mark_k has posted another tool above that has button-checking added as well. Before worrying about getting it to work in Startup-sequence, you should try to get it working by manual execution of the tool to determine which (GVPCPUCTL or Boot68000) tool works on your system.