50g - overclock

[Zaphod]

From the file cat.txt, included in the download:

Quote:HP49G+ Clockspeed Adjustment Tools - HP-CAT - V2.00


CAT is a suite of utilities for adjusting the frequency of the HP49g+'s processor.


Please note that Thomas Rast's excellant ARM launcher (launcher.bin) is needed to run any of these programs. Also these tools may have side effects, such as altering the speed of the realtime clock or preventing Calc-PC communication. A power cycle should always return the calculator to normal operation.


Included in this release:

TURBO - for executing commands at 203MHz

SLON/SLOFF - for executing commands at 12MHz

Cxx files - for running at various clockspeeds normally. These overclock memory.

Also included is C124s, a 'safe' overclock. It doesn't overclock memory and should work on any HP49G+. This pushes the CPU to 124MHz.

CFIX - This undoes the effects of TURBO or any of the Cxx files.


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1) Slow Mode Tools (SLON/SLOFF)

These enable/disable the Procesors 'Slow Mode'. This sets the clock speed to 12MHz instead of the usual 75MHz.

300! normally takes ~1.5 seconds. In slow mode, it takes about 10 seconds.

This might be useful for old games that run way too fast. While arcade
games wil probably run too slowly, and old greyscale games won't work
properly, some other puzzle games (sokoban etc?) may now be slow enough
to control sucessfully.

SLON will enable slow mode - SLOFF will return to normal 75MHz speed.

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Usage:

make a program as follows

<<SLON *Target Program Here* SLOFF>>

Save this program and run it. The target program will now run much slower.

You will see the screen glitch for a moment - I will work on removing
this in future versions if anyone cares.

Please note that SLON and SLOFF are matched - do not combine them with the other commands.


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2) Clock Adjustment Utilities (Cxx)

Several files names Cxx, such as C34 and C90 are included in this file. These adjust the main PLL frequency. C34 sets this to 33.75MHz, C90 sets it to 90MHz etc. Speeds greater then 75MHz overclock your calculator.

Note that the effect of the Cxx utilities lasts until the next power cycle. So you can run C90 once at bootup, and all tasks will execute faster until you turn the power off. Also note that these might run on a HP48gii to bring it up to the speed of a 49g+.

Also the screen appears to flicker abit when running at 33.75MHz. I will fix this if someone emails me and asks nicely.

These Cxx utilities generally overclock the memory bus as well as the CPU. Some calculators crash when running at higher then 90MHz.

A "Safe" option has been included.

'C124S'

overclocks the CPU to 124MHz, but also keeps the memory operating at the speed selected by HP. In theory this should work on any 49G+. Please let me know if it doesn't.

The command 'CFIX' will set the CPU back to 75MHz, and the LCD and memory speeds back to their default settings. You could create a program, <<C90 INTVX CFIX>> to set the CPU to 90MHz while running the INTVX command, and restore itself to 75MHz afterwards.


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3) Turbo Mode

If you like to live dangerously, 'TURBO' is for you :-)

Turbo slows down the memory bus, lowers the LCD refresh rate, and clocks the CPU at 203MHz(!). At these speeds, the keyboard reading routine in the OS no longer works correctly. 203MHz is not suitable for general use like the Cxx utilities. Instead you must use TURBO and CFIX in a program to accelerate a series of tasks.

Typical Usage:


Make a program like

<<TURBO _Some_Command_Here_ CFIX>>

and run it. This will run the target command at 203MHz, and restore the system back to 75MHz when done.

The 49G+ was designed for 75MHz operation - 203MHz is _way_ outside the specs. There's a chance TURBO will lock-up your calculator.

Try not to press any keys while TURBO is operating, due to misread keys being placed in the buffer. If your asm programs use TURBO, I suggest turning off the keyboard scanning.


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A quick example timing - Last Stack Disabled, timed with TEVAL

800!

16.43 seconds normally

10.35 seconds at 119MHz (C119) *

12.3 seconds at 124MHz (C124S)

8.5 seconds at 203MHz ( << TURBO 800 ! CFIX>> )

* The memory is overclocked in this setting, and may not work on all 49G+'s.

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If you fine these utilties useful for anything, please drop me an email at al.borowski@gmail.com. That way I know I'm not wasting my time programming them.

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Disclaimer: These programs temporarily alter internal settings in your calculator. Even though I have tested them and I belive they are safe to use, I might be mistaken. Overclocking may damage your calculator in the long term. Run at your own risk.


cheers,

Al Borowski

al.borowski@gmail.com
12 July 2004