"Turbo"

[Claudio L.]

(04-27-2014 03:38 PM)jebem Wrote:  1) Overclocking the 49G+
Some HP models, for instance the 49G+ model, can have the ARM cpu "accelerated" up to 203MHz (in several steps) and back down to 12MHz, just using software tools created by Alistair Borowski (Clockspeed Adjustment Tools - HP-CAT).
I know this is old news, but here it goes the link to the tool:
http://www.hpcalc.org/details.php?id=6081

2) Overclocking the 48GII
Apparently at least one of the 48GII different production batches also works with Alistair Borowski tools, despite not all the cpu speeds will work.
Well, this is a 49 series machine hardware, despite the name, but there are two production batches: the latest production batch uses 4 cell batteries (closer to a 50G?), while the initial batches uses just 3 batteries and a not so good keyboard.

3) Overclocking the 50G
I read some reports claiming the Alistair Borowski tools will not work on the 50G at 203MHz. Well, it should, if we assume that a 49G+ hardware is essentially the same one used in the 50G. Perhaps there are differences in batch productions (for example, if the 50G memory access is running without wait cycles, while the 49G+ can be using wait cycles, who knows!).
HP (or should I say Kinpo?) use to do silent changes, while keeping the same model number.
On top of that, there are different firmware versions for these HP calculators, and it may affect the results as well.
I couldn't find any documented work detailing all the different conditions.

4) Or forget about turbo/overclocking... Try an HP calc emulator/simulator on Windows or Linux or even on your preferred Android/iPad mobiles instead... now that is real "turbo" mode!
Some examples:
http://www.hpmuseum.org/cgi-sys/cgiwrap/...i?read=867
http://www.hpcalc.org/hp48/pc/emulators/
http://sim41.webcindario.com/sim67.htm
http://www.limpidfox.com/hp67.htm
http://www.cneufeld.ca/neufeld/hp67/hp67.html
https://play.google.com/store/apps/detai....limpidfox

Actually, Al's tools were never very safe, as they change the clock of the CPU only, and that affected the memory speed as well (you hit it right in the nail).
To do proper turbo nowadays, you need to use hpgcc. The clock changing procedure was completely reimplemented in hpgcc and hpgcc3 to make it safe to use. It adjusts CPU clock, but also the memory clock is adjusted to keep the memory working at the same original speed, so it doesn't crash.
If somebody were to improve Al's tools by looking at how hpgcc corrects the memory timings, it could be made to work consistently on all models.
However, I'm not sure this qualifies as overclocking. The ARM chip in the 49 series has selectable clock up to 200 MHz, so we are never exceeding any design parameters.
So this is one of the cases where "Turbo" is not the same as overclocking.

Claudio

[Raymond Del Tondo]

So I'll throw in my software Turbo for the HP 48G series: SpeedUI.

If you're used to the normal, built-in UI, you'll see and feel the difference immediately:-)

[Jim Horn]

Yes, the HP-67 could be run at roughly double speed as well by changing the capacitance of its LC clock oscillator. If you lifted one end of the stock capacitor from the circuit board and wired a second smaller value in series with it, it ran faster. By shorting the added capacitor, it ran at the original speed.

My '67 ended up with a flush mounted toggle switch that did just that as well as a momentary contact phase zero interrupt pushbutton that allowed creation of virtually any desired bit pattern in memory. Great for creating custom register data on cards to explore the then-new HP-41C: one weekend I pressed around 20,000 keystrokes doing same. Aah, the days of free time!