Accelerator Cards

[sim085]

Hi,

I have some questions regarding accelerator card related to the processors and the memory used on them.

Regarding the processors; where the processors of the accelerator cards all the same. For example the processor 030 on the Derringer and Viper and VXL, GVP530 etc where manufactured by the same manufacturer or they where manufactures by the vendors of these cards?

If they are the same then how come these cards come with different memory configurations; some with 8MB others with 32MB while others with 128MB? Shouldn't all these be able to access the same amount of addresses in memory?

Regards,
Sim085

[sim085]

So is it possible to upgrade such accelerator cards to support more memory? For example can the M-Tec be upgraded to 32MB of memory? (maybe using the same solution to upgrade the A500+ to 2MB chipram)!  

[sim085]

(Note that I ask these question to learn the architecture more then because I want to try this out ... I do not have any soldering skills so far).

From my understanding the 030 processor is connected to an (Memory Management Unit) MMU. Now between the processor and MMU there should be all the addresses available to the processor. Therefore the limitation would be between the MMU and the actual Memory chips. Is this right?

Also what do you mean by OS to recognise the RAM? You mean workbench accesses the Memory directly without the use of an MMU?

[sim085]

What is confusing me is this; What happened if the processor wanted to store something in an address which was not there? Or this never happened since the processor knew the maximum amount of memory allocated to it?

Also does the operating system talk to these interface chip? or it only talks with the processor? and aren't these interface chips like an MMU?

 

[sim085]

Ok I think I understand (don't do that surprised face please :-)) The operating system would tell the process what instruction to execute and where to store the result and the operating system would know the allowed memory space because of this small program you mentioned. is this right? or I am confusing things?

[sim085]

Thanks, I will try to search for that book.

... just another question about something which has been confusing me a lot ...

In the Amiga Hardware Database there is written that the A500 can only have a maximum of 32MB fast RAM on processor board (i.e. the accelerator card).

http://amiga.resource.cx/mod/a500.html

That said how come the Viper came with 128MB of fast RAM on the processor board? Is the extra RAM for nothing (which I do not think)? and what determines the limit of 32MB mentioned in Amiga Hardware Database?

http://amiga.resource.cx/exp/ematrix530

I think I asked a similar question about chip ram but I am still not sure if I understand this correctly!

[sim085]

From the amiga memory layout there are some things I can understand and some which I cannot (surprise surprise :-))

Always talking from the A500+ perspective (since that is the only machine I have);

'2MB chipram' refers to the 1MB chipram which comes on the motherboard and the 1MB chipram which can be added in the trap door slot.

'8MB Zorro2 autoconfig space' refers to the ram that can be added through for example a side slot expansion such as the GVP A500HD8+ which takes 8MB and the A590 which takes only 2MB if I remember correctly.

'512KB slow ram on A500' I cannot understand ... isnt this the ram that comes on the motherboard and therefore part of the chipram?

'3.5+GB free for use by 32bit accelerators' refers to the memory space that can be on an accelerator card.

Are the above correct; as I said the thing that confused me the most is that 512KB.

The memory table is very helpful to understand the concept. Strange to see that memory wise an A500 can be better equipped (if wanted) then an A4000 :-P

[sim085]

Ok thanks a lot to everyone for all the answers. I will need some time to understand all this but things are much more clear now

Something else completely different now; What determines the maximum processor that can be used on an Amiga. What I mean is that for the A500 you only find processor up to 040 while for the A4000 you find processor up to 060 (I do not know if more) and even PPC. What determines what type of processor can be used.

Also what is the use to have a processor running at 50Mhz if the socket to which it is connected has only a data transfer of 7.14 MHz (if I understand the specs here correctly: http://amiga.resource.cx/mod/a500.html).

[sim085]

Yes but you need the Zorro2 bus expansion because the blizzard 2060 connector is for an A1200 and not for the A500 processor socket right? What I mean is that if (theoretically or fantasy speaking for some) you put an 060 an a board which can connect to the processor socket of an A500 then the processor would still work. or?

[sim085]

countzero wrote:
I was talking about something like this which gives an A2000 processor slot (Zorro2 is irrelevant),

Yes I understood that; what I meant is that you need one of those to connect a blizard 2060 because the connector is different then the connector of an accelerator card for the A500.

countzero wrote:
yes it should work.

I do not want to push it but does this also apply for a PPC? I know you already said it should work in your previous post. However I was thinking that a PPC recieves instructions in a different way then an 680X0 processor. If so then only an OS which can send such instructions can work (example OS4.0) and I do not know how much you could fit that on an A500 with a PPC.

Again I must repeat that this is just hypothetical speaking. I am just trying to understand the concepts behind accelerator cards not actually thinking to build one since I have no electronics experience ... sorry for any one who was hopping for that ... maybe one day in the future ;-)

[sim085]

but how is it possible ... how can the same instructions used for the 680x0 processor also work on a PPC processor? I can understand between different 680x0 processors but not between completely different processors!

[sim085]

aaaa ... i checked the video again and he puts the 68060 processor back on the PowerUp Dev board...

This is such an interesting subject and I personally could keep asking one question after the other :-)

Thanks for all the answers ... there is much to think about after this thread :-)

 

[sim085]

Piru wrote:
But seriously: While A500 with PPC is in theory possible it really isn't worth the trouble. :-)

I understand that and I do not have plans to put a PPC into my A500+ :-) I am just trying to figure out what the limitations are.

However one can imagine (or a better word is 'fantasies') an accelerator card which can emulate different processors ...

You can have a board with any type of processor on top of it and some extra ram as well. the processor would actually run only a single program which would be an emulator. The instructions received from the Operating System would be translated and then executed. Like this you can have a single board which can be configured as a Viper, Derringer, Blizzard, etc ...

I know some will say why not use WinUAE and get it done with, but would something like the above be possible?

[sim085]

Piru wrote:
Sure it would, but the price would be so hideous you could get a couple of recent AMD or intel setups for the price.

Yes I know what you mean ... and as I already said I do not have the knowledge nor the time to do something like that ... it was just a (quick) thought after all the posts :-)

However it was nice to learn so many things on accelerator cards and more importantly on how memory was managed in the Amiga.

[sim085]

@rkauer

So an empty PCB costs that much!!? How does it work? you send the PCB design to a company and they send you the empty PCB board? or?

I do get your point however. I started this thread just to get a better understanding about Accelerator Cards. I do fantasies some times of building one myself when I will have the time to learn how to do so; however such a time is very far away at the moment ... if it will ever come close I do not know!