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Discussing the Open Source FPGA Amiga Project
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 Post subject: More "slow" RAM?
PostPosted: Sun Feb 28, 2010 1:01 am 
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Joined: Sun Feb 22, 2009 5:02 am
Posts: 175
I'm pondering...
In the memory setting I can configure chip memory to be 0.5, 1.0, 1.5 or 2 MB, and in slow memory none, 0.5, 1.0 and 1.5 MB. Are there any good reasons for not being able to have more slow mem if one set chip mem to for example 0.5 MB?

I would love to test something with 512k chip RAM and 3MB slow RAM :)

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 Post subject: Re: More "slow" RAM?
PostPosted: Sun Feb 28, 2010 11:02 am 
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Joined: Mon Dec 01, 2008 10:11 am
Posts: 197
There is only 1.75 MB reserved in Amiga's memory map for Slow RAM. Some Kickstarts are only able to detect 1.5 MB of it.


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 Post subject: Re: More "slow" RAM?
PostPosted: Sun Feb 28, 2010 12:35 pm 
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Joined: Sun Feb 22, 2009 5:02 am
Posts: 175
OK, I probably have misconception of what "slow RAM" is. ;)

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 Post subject: Re: More "slow" RAM?
PostPosted: Sun Feb 28, 2010 9:21 pm 
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Joined: Sat Jan 17, 2009 10:13 pm
Posts: 106
this comes handy
http://www.ntrautanen.fi/computers/hard ... memory.htm

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 Post subject: Re: More "slow" RAM?
PostPosted: Sun Feb 28, 2010 10:10 pm 
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Joined: Mon Dec 01, 2008 9:58 pm
Posts: 1568
Location: .de
There is some russian Amiga600 memory expansion card, which also support slowmem and additional memory auto detected by Kickstart. I cant find the posting any more but remember a ShowConfig screenshot. There also was some megabyte of memory located at $Axxxxx if I recall it right. The board just provide address logic, no auto-config pal/gal chips.

For the Minimig V1.x I also thought about additional memory expansion. It would require another piggy-back chip at IC6 (3rd level) and just some additional code for the FPGA to address it. If somebody know this info or address range, I would like to test it out :)

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 Post subject: Re: More "slow" RAM?
PostPosted: Tue Mar 02, 2010 1:39 am 
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Joined: Sun Feb 22, 2009 5:02 am
Posts: 175
So what would it take to get real fast ram on the current minimig? A memory card piggybacked ontop of the 68000? :)

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 Post subject: Re: More "slow" RAM?
PostPosted: Tue Mar 02, 2010 12:43 pm 
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Joined: Mon Dec 01, 2008 9:58 pm
Posts: 1568
Location: .de
kolla wrote:
So what would it take to get real fast ram on the current minimig? A memory card piggybacked ontop of the 68000? :)

This only work in real Amiga hardware env. Minimig external devices act different and do not allow this any more.
The 68SEC000 for example will not get hold by chipset/Agnus due DMA access. On Minimig it run permanently and in some sort of dummy loop cycle for this time.

Real Fastmem require a rewite of FPGA internal bus access. It is not impossible to do but also require faster RAM chips too.
Perhaps its better to let the ReplayBoard take over this, it already provide much more memory and FPGA space.
Current Minimig (V1) board is designed to be a Amiga500/600 reimplementation and for now it really, really do its job very good!
Compatibility is as high as even possible (approx. 99%) and the given capacity is almost fully used.
Brilliant job and thank you Jakub :)

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 Post subject: Re: More "slow" RAM?
PostPosted: Tue Mar 02, 2010 11:57 pm 
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Joined: Sun Feb 22, 2009 5:02 am
Posts: 175
boing4000 wrote:
Real Fastmem require a rewite of FPGA internal bus access. It is not impossible to do but also require faster RAM chips too.
Ah, well - I'll just leave it at that :)
Quote:
Perhaps its better to let the ReplayBoard take over this, it already provide much mor memory and FPGA space.
Indeed, can barely wait... hopefully there will be more teaser vids on youtube? *hint hint*
Quote:
Compatibility is as high as even possible (approx. 99%) and the given capacity is almost fully used. Brilliant job and thank you Jakub :)
I second that - Thanks alot, Jakub! :D

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 Post subject: Re: More "slow" RAM?
PostPosted: Sun Sep 05, 2010 7:35 pm 
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Joined: Thu Jan 29, 2009 9:29 am
Posts: 36
Location: Lorraine - France
What is the best memory configuration for the Minimig 2Mo ?

I tried many combination and some time I had strange results:
- 0.5 Mo Chip + 0.5 Mo Slow, work fine but at 40mhz speed in SysInfo
- 0.5 Mo Chip + 1.5 Mo Slow, work fine at 52mhz !!!
- 2 Mo Chip, work fine at 41mhz
- 1Mo Chip + 1 Mo Slow, failed to launch SysInfo on Workbench Classic 3.1 Guru error.
- 1.5 Mo Chip + 0.5 Mo Slow, Minimig don't boot and give me a Red / Yellow flashing screen

I use the last version of Yaqube firmware with is ARM.

What about you ? Is it better do have more slowram ? Or is the basic 0.5 + 0.5, is better for compatibility ?

Thanks for your help ;)

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 Post subject: Re: More "slow" RAM?
PostPosted: Sun Sep 05, 2010 9:05 pm 
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Joined: Sat Jan 31, 2009 9:01 pm
Posts: 82
Location: Malta
On the minimig, 0.5MB is allocated to store the Kickstart. A further 0.5MB is allocated for the Action Replay (if enabled). On a 2MB minimig this leaves you with 1.0MB (AR3 on) or 1.5MB (AR3 off) which you can freely allocate.

You just need to be careful that you don't exceed the remaining memory when selecting the memory partitioning options.
My personal preference would be:

(1.5MB - AR3 off)
1MB chip + 0.5MB slow (more space for chipset data - useful for tools such as DPaint, etc)
0.5MB chip + 1.0MB slow (more space for program data - more chance for software to benefit from cache)

(1.0MB - AR3 on)
0.5MB chip + 0.5MB slow

You need to have some slow memory in the system for the new turbo cache to work. So, it doesn't make much sense to allocate all RAM as chip.

Edwin

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