(48GX) SpeedUI 14.01 released:-)

[matthiaspaul]

(08-16-2016 11:50 PM)JDW Wrote:  Here is an exact quote from the EBAY seller regarding his FRAM cards for the 48GX:

FRAM cards are much faster then older SRAM cards, but the gating factor is
not performance of the card, but performance of HP48GX reads and writes.
FRAM card maxes out performance capabilities of HP48GX,

This is correct up to this point.

Quote:so in real terms it will only be slightly faster then older SRAMs. My guess is about 20-30% improvement

This part of the seller's statement is incorrect per the explanation given here:

http://www.hpmuseum.org/forum/thread-656...l#pid59836

The gain will be exactly 0% unless there would be some means (for example by extra card pins) to communicate back the speed of the (card) memory to the processor (and for the processor to have some means to change its timing accordingly). I am not aware of such means in the HP48.

In theory, there could be some gate-protected in-band-communication to communicate chip performance parameters back to the processor (like the trick used for software-programmable write-protection in the FRAM chip linked above, but this is something specific to the chip, and not following a standard). I'm not aware of the usage of any such in-band-communication in conjunction with parallel asynchronous SRAMs at all, but even if such may exist somewhere today, I'm quite sure it didn't in the early to mid 1990s when the HP48 series was designed.

Greetings,

Matthias