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From: Veli-Pekka Nousiainen on 11 Oct 2006 02:46
pynnonen wrote:
> If the HP 50G can get its power from the USB, why not also kick up the
> ARM9's clock from 75Mhz to 203Mhz? When it is disconnnected, drop it
> back down to 75Mhz.

Perhaps next model :-D
Currently the SRAM & LCD can't cope with that speed
Perhaps 120MHz if designed to do so

> Also, many USB devices charge via the USB port,
> why not do the same for the HP 50G?

1) safety
2) cost will go higher because of testing
- nice idea though

> Also, I called the HP Help Center, and they were not aware that you
> could run the HP 50G from the USB. I even tried removing the
> batteries, and it still worked.
>
> If anyone from HP is a calculator engineer, please inform them of this
> capability.
>
> Is the HP 50G USB port High Speed(480Mbs) or Full Speed(12Mbs)?

? It uses serial speed 115200, so slow mode is enough
I wonder if this could be speede up in the future
while keeping everything reliable
ROM upgrade speed could be different from I/O speed

waiting fo HP-51G ??


From: Joe Horn on 11 Oct 2006 06:33
James M. Prange wrote:

> I'm not so sure that the operating system "knows" where the power
> is coming from, only what the power supply voltage is. The switch
> between drawing power from the battery and getting it from the USB
> port could be entirely in hardware, without ever telling the processor
> or operating system about it.

The OS knows, since the "ON-F, 8" battery test displays whether the
machine is running off batts or USB power. The display changes
instantly between "Battery Normal" and "USB Power" (or something like
that) when a powered USB cable is plugged in or removed.

Anybody know the entry point for testing whether the power is coming
from the USB port? It'd be useful in long-running programs, rather
than constantly testing the low-bat status.

-Joe-

From: Gene on 11 Oct 2006 08:06

Veli-Pekka Nousiainen wrote:
> > Also, many USB devices charge via the USB port,
> > why not do the same for the HP 50G?
>
> 1) safety
> 2) cost will go higher because of testing
> - nice idea though

Gene: HP does not do this, probably for liability reasons. Consumers
could put in all sorts of batteries, alkaline, NIMH and Nicad all in
the same set. It would add a great amount of expense to have the 50g
know what type was in there. All it would take is one explosion while
charging to have HP sued in today's lawyer-conscious society.

I'd be shocked if we ever saw the ability to charge through the USB
port.

From: Veli-Pekka Nousiainen on 11 Oct 2006 12:03
Gene wrote:
> Veli-Pekka Nousiainen wrote:
>>> Also, many USB devices charge via the USB port,
>>> why not do the same for the HP 50G?
>>
>> 1) safety
>> 2) cost will go higher because of testing
>> - nice idea though
>
> Gene: HP does not do this, probably for liability reasons. Consumers
> could put in all sorts of batteries, alkaline, NIMH and Nicad all in
> the same set. It would add a great amount of expense to have the 50g
> know what type was in there. All it would take is one explosion while
> charging to have HP sued in today's lawyer-conscious society.
>
> I'd be shocked if we ever saw the ability to charge through the USB
> port.

In good old days HP simply warned about using anything else
than official HP battery pack
My HP-41CV was powered by Alkalines, but the later HP-41CX using the Pack
Simply: HP releases Battery Pack for the HP 51G and allows loading via USB
(or better yet: the pack is Litium-Ion)
BTW
HP iPAQ machine have rechargeable batteries and no explosions!


From: Gene on 11 Oct 2006 12:24

Veli-Pekka Nousiainen wrote:
> In good old days HP simply warned about using anything else
> than official HP battery pack
> My HP-41CV was powered by Alkalines, but the later HP-41CX using the Pack
> Simply: HP releases Battery Pack for the HP 51G and allows loading via USB
> (or better yet: the pack is Litium-Ion)
> BTW
> HP iPAQ machine have rechargeable batteries and no explosions!

Gene: Yes, the good old days before lawyers started trying to rule the
world.

With the 41CX, you could not recharge N cells in the machine. It tood a
special battery pack. I dont' see any room in the 50g battery
compartment for that sort of pack.

And, about the iPAQ, not only does that increase the cost, the design
was probably created to detect what type of batteries are in there.
That (to my knowledge) was not the case with the product tree leading
to the 50g (48sx, 48gx, 49g, 49g+).

So, changing it now would cost $XXXX (whatever), would benefit a tiny
tiny portion of their users, and would potentially expose them to
lawsuits anyway. And, any time spent re-engineering the power circuits
of the 50g is time HP does not have to bring out the new HP41CX+++IIGX
machine I saw in a dream last week. Seriously, if HP spent 4-6 months
doing this, would it lead to even a blip increase in sales? No way.

I'd bet money this will never happen.

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