A500 gvp HD8+ and VXL*30

Hello there,

I have a little issue trying to use those two boards together. It seems that there is a RAM problem or something.

My config :

- A500+ with A502
- ROM 3.1 and WB 3.1
- GVP HD8+ with 8mb RAM
- VXL*30 + 8mb RAM add on

1) When I plug only the GVP HD8+ (ROM 4.15, 8MB RAM) it works fine. Software and whdload games are working well.
2) When I plug only the VXL*30 + 8MB ram add on : it works fine too (I am able to run the WB from a floppy and to launch software
3) When I plug them together (without adding the GVP RAM to avoid any conflicts), The WB starts as it should but I cannot launch whdload games or software using fastram (the A500+ is freezing or do a guru). It seems that I have a RAM access problem.

So I decided to test ram of the VXL :

1) Without the GVP connected, the ram test find no errors
2) With the GVP connected, the ram test failed

The mask tranfert of the HDD is well configured according to the VXL documentation.

I saw on Amiga ressources that for the GVP HD8+ :

"problems may arise with the combination of A500, 8372A Agnus and an internal memory expansion with CPU or Gary adaptor - a trace has to be cut to solve the problem "

Could you tell me what is the trace they are talking about ?

Thanks.

You're going to have to use one of the memory expansions NOT both. Disable the GVP's ram and it should be fine. GVP ram is 24bit so 8mb from that would be the maximum, the VXL should be 32bit, so you'll have quicker 8mb ram.

So basically, use the VXL's ram and the GVP's HDD.

Had to do the same thing with my alfapower which had 8mb and 68020i which had 4mb. Had to use the 4mb as the 68020i didn't allow me to disable it's ram :(

Thanks for the reply.

As I said I disabled the GVP RAM to avoid any conflicts and only use the VXL one.

If I use both, the GVP ram does not appears but it does not conflict.

The VXL RAM is recognized as 24bit. We can map this RAM High so that it is recognized as 32bit but we need to have another RAM expansion such as the GVP one. If I activate the RAM of the GVP AND maphigh the VXL ram, I have 16mb recognized but it is the GVP which is in first so the system is slow... Moreover I am pretty sure that If I use more than the "first 8mb" RAM, I will have same problems when it wil use the VXL RAM.

Hi,
you could check which RAM address use both cards. Maybe they are overlapped.

Best regards

FD

Thanks Fielday.

In fact, someone on Amiga.org said there should be a wire connected between PAL chip and the RAM module of the VXL to be able to use HDD controller with DMA transfer like GVP ones. I do not have this wire ! I think here is the problem resulting in bad RAM transfer. I will solder one as soon as possible and will let you know guys. This way it can help someone in the future ;)

Cheers.

I have soldered the wire and no luck, still the same problem. However, I put the Jumper on 2MB position on the VXL and ran the RAM test again. It worked ! I can play whdload games and other software without any problem. I think I have one or more defffective ram chips...

The only question is : why when I run the ram test on 8mb position on the VXL without connecting the GVP I have no error... ?

My bad, I have no other HDD controller without DMA transfer to see if it does the same problem on 8mb position.

Hi,
first you have to check both address ranges. When both devices are autoconfigured maybe they use the same address range. You can prove this with avail, sysinfo or showconfig. Hope you will see, that your VXL bind her RAM outside of the 24-bit address range.
Poste your results here and we could have a look.

Best regards

FD

Ok I will do it.

As far as I remember, when mapped low, the VXL RAM is recognized as 24bit RAM (starts at 20000...) and sysinfo does not see the the GVP RAM.
When mapped high it is recognized as 32bit RAM (starts at 80000...) but is not recognized by the system at boot. I need a ram expansion on the zorro port and use the addmem utility to see the VXL RAM. The problem is that the system boots first on the GVP RAM, this means that ram access are very slow... but nice to see 16mb RAM on the A500. Other problem, even if mapped high (so outside the 68k memory space), the ram test does errors...

Anyway I will take some screenshots ;)

Cheers.

Here are the results :

Picture named :

2&GVP : 2mb jumper on VXL + 8mb activated on GVP
Results : the system works fine, only 2mb 24bit from VXL is seen by the system

8&GVP : 8mb jumper on VXL + 8 mb activated on GVP
Results : The system boots on WB (8mb 24 bit recognized) but everytime I try to launch games or software, it crashes

8&GVP&maphigh : 8mb jumper on VXL + maphigh jumper on VXL + 8mb activated on GVP + addmem utility
Results : The system works, 16mb is recognized but the GVP RAM is in first resulting in a slow system (x1.7 compared to a standard Amiga 500). The VXL RAM is recognized as 32bit RAM and the GVP as 24bit RAM.

8 without GVP : 8 mb jumper on VXL, the GVP is not connected at all, boot from WB3.1 floppy disk.
Results : the system seems to works fine, I did launch some software but I do not have many on floppy disks.


The funny things is the only configuration I want does not work at all...

Something to add :

In 8mb VXL + 8mb GVP configuration, The VXL ram test program see 2 VXL Ram board with each 8mb. Same configuration but without the GVP, the same utility see only one board :unsure:


EDIT : I have pull off all the 16 Dip ram and pull on them again and mixed them (so they are not at the same place) : Now, when mapped high the VXL ram is in first so I have a 32bit system (very responsive !!). However, only the 2mb configuration works, everytime I set the VXL Ram on 8mb the system crashes when accessing Fast RAM... I should try another Ram test utility.

Hi,
could you check at your hdtoolbox which mask is configured? If you like you can set it to: 0x7FE00000 but be careful, maybe your system won´t reboot. So keep always a backup or create a second boot partition with your old settings. Settings above will disable the DMA on your GVP controller.

Best regards

FD