64Mb Simms on a CyberstormPPC ? Also single Simm and 50ns mem..

[Framiga]

IIRC the answer was . . . nope :-( due the low ram bandwidht.

Atari project uses SDram . . .pity.

[AdMartin]

The problem with many Amiga accelerators is that their memory controller only supports 2k refresh, whereas most newer SIMMs use 4k refresh. In that case, only half of the memory is 'seen' by the memory controller. Some of the latest designed Amiga accelerators, like Blizzard 1260 and BlizzardPPC, support 4k refresh, but I don't know about the Cyberstorm line.

Speaking of memory, I just won an auction for two 128MB 50ns 72-pins SIMMs on eBay. I plan to use them in my BlizzardPPC, but the problem is that the DRAM chips on it are designed for 3.3V whereas standard SIMM voltage is 5V. We'll see what happens...

[Jose]

This reminds me of something.. Were there 40ns 72 pin Simms that worked on Amiga accelerators? ...35ns ones?  8-)

[Hyperspeed]

Eeek!

I wouldn't try putting a 3.3v SIMM into a 5v Amiga accelerator. Are
you sure it's not DIMM or something?

Some are specifically made for laser printers or synthesizers/samplers
so please check first!

There are 2x types of SIMM - FPM & EDO. They can come with parity and
ECC (error correction).

I would reccomend all Amiga owners to get FPM (Fast Page Mode) memory
as this is the older type and offers full compatibility.

FPM reached 60ns in speed, 50ns would be EDO. Blizzard cards have been
known to have compatibility issues with EDO and some older Mac Quadras
have been fried by EDO (check Google).

I've not heard about the 2k/4k compatibility issue but it's worth
taking into consideration. You should always check the code printed on
the DRAM chips of each SIMM - the numbers correspond to specific
attributes.

I'll attempt to paste the way to work them out:

[Hyperspeed]

Format :        XXX AA BB CC D -EE




XXX: Manufacturers Identification Code:
______________________________________                
                GM    Goldstar/LGS
                HM    Hitachi
                HY    Hyundai
                HYB   Siemens/Infineon
                K     Samsung/SEC  (new code)              
                KM    Samsung/SEC
                LH    Sharp
                M5M   Mitsubishi            
                MB    Fujitsu            
                MCM   Motorola
                MN    Panasonic/Matsushita
                MSM   OKI
                MT    Micron              
                TC    Toshiba
                TMS   Texas Instruments
                uPD   NEC
                   
AA : Total Number of Megabits:
_____________________________
                 1 :   1 MBit
                 4 :   4 MBit
                16 :  16 MBit/4k  Refresh
                17 :  16 MBit/2k  Refresh
                18 :  16 MBit/1k  Refresh

BB : Internal Organization (Data Width):
_______________________________________
                10 :   1 Bit  (1 MBit Chips: 0 = 1 Bit)
                40 :   4 Bit
                80 :   8 Bit
                16 :  16 Bit

CC : I/O Mode:  
_____________
                 0 :     Fast Page Mode (FPM)
                 1 :     Nibble Mode (NM)
                 2 :     Static Column Mode (SCM)
             3 - 9 :     Fast Page Mode mit Extended Data Out (EDO)

D :  Package Information:
________________________
                  J:     SOJ- package.
                  T:     TSOP Type-II package

EE : Access time in nano seconds.
________________________________
Sometimes the zero is omitted.
In that case the number should be multiplied by 10 so that the speed falls into the 30 to 150ns range.

Examples:  TC51 1 0 00 -60  --> Toshiba,  1MB, 1bit (1Mx1), FPM, 60ns
           HYB51 4 4 00 -60 --> Siemens,  4MB, 4bit (1Mx4), FPM, 60ns
           HM51 18 16 0 -6  --> Hitachi, 16MB/1k refresh, 16bit (1Mx16),FPM, 60ns

[Hyperspeed]

Sorry to post for a 3rd time in a row!

:-D

Hope that DRAM identify chart looks OK on your browser. Seems to read okay on iBrowse but not very pretty on older Voyager.

Just a few more comments:

SIMMs came in 130ns to 30ns but I think the 30ns were seriously incompatible EDO DIMMs that an Amiga wouldn't be able to work with anyway. Stick with 60ns or 70ns.

Remember that a 70ns SIMM could well be 65ns as it's standard to round the figure up.

The Cyberstorm cards have a 64-Bit memory address system so need SIMMs to be installed in matched pairs. This means they need to be identical in every way and also put in all four slots if you wish to fill the 128mb max. If you use only 1x matched pair (2 SIMMs) then use either slots 1&3 or slots 2&4.

* Best 128mb SIMMs are 16-DRAM 60ns FPM - usually all double-sided.

* The Quikpak A4000t's 060 CPU slot supported 50ns EDO, the Picasso-IV had 4mb of 45ns (50ns) EDO. But stay away from it if possible on older machines or if you have unbranded memory. Any trouble then hold ESC on bootup to switch on/off memory pre-charge.

* Blizzards require minimum of 70ns (SCSI-IV will send you into 70ns mode regardless). Motherboard is 80ns - ROMs are 160ns/200ns. Maprom is an obvious advantage on Blizzard cards!

* Blizzard 1230-IV supports 256mb whereas Cyberstorm supports 128mb.

:-D :-D :-D

Go 256mb '030!

* Some SIMMs require them to be installed in 2x or 4x and will only appear as half their size in single units. This could be server memory (fat and ugly composite SIMMs made up of loads of little 256k DRAMs)

:-)

[Jose]

@Hyperspeed
That's a pretty cool chart, thx.

"Any trouble then hold ESC on bootup to switch on/off memory pre-charge..."

Out of curiosity, any idea of what that does?

[AdMartin]

Eeek!

I wouldn't try putting a 3.3v SIMM into a 5v Amiga accelerator. Are
you sure it's not DIMM or something?

Yes. I used to have two 128MB 50ns SIMMs in my BlizzardPPC, but had to sell them because of a need of cash. They used the same Micron 3.3V DRAMs as the ones on these SIMMs, that's why I'm willing to take the chance.

/Martin

[Hyperspeed]

As I've ranted on many threads, I'm not a big fan of EDO. I like to
play safe with the standard 60ns FPMs.

Phase5 realised that some poor quality SIMMs weren't working with the
Blizzard 1240/1260 and opted for a special menu on the PowerPC cards.

On bootup you hold down Escape and the menu appears. I'm not sure what
precharge does but it's going to be something more tolerant to allow
Taiwan SIMMs to work.

:-D :-D :-D

One big problem that has to affect a lot of people is the oxidisation
on the contacts (leads) of a SIMM. From what I've been reccomended the
best thing to do is get a fibreglass pen or cleaning solution from
Maplins and polish the contacts up until they gleam. This way there is
no resistance from Blizzard to SIMM.

Some cleaning fluids are lubricating switch-contact cleaners -
probably best to avoid these and get dedicated PCB contact cleaners
from a reputable computer source.

Funny though that the so-called `Gold' contacts on Phase5 boards
tarnish into a murky yellow. Gold doesn't tarnish and it is the
DEFINITIVE cause of SCSI errors on my Blizzard1260/SCSI-IV combo.

One error that occurred was the last 4mb of my 64mb SIMM not showing
on Workbench, when it was filled I would crash. I pulled out the SIMM
and put it back in and now everything is fine (the in-out action had
scraped clean a dirty contact I suppose).

One other thing, Micron SIMMs don't seem to follow that DRAM chart too
well and some SIMMs won't follow it at all. Best to do a bit of
research, testing and Googling.

;-)