Re: CF card and the Sharp PC3000/HP95LX experiences (fwd)

[Chrismeister <chrisn@xxxxxxxxxxxxxxx>]

Hi Christian, Sven and all on the list!

Well I figured I'd better do some tests to check this out (having a Sharp
PC3100 and 32M Sandisk CF card), so I hooked it all up to the external
power supply and multimeter as best I could.  As reiterated in the notes at
the bottom of the table, these figures are just rough averages measured in
an imperfect environment, so should be taken with a grain of salt.

					CURRENT in mA	
EVENT				(LP on)	(LP off)	NOTE
-----				-------	--------	----		

OFF				5.3		5.3		5
IDLE (with no key pressed)	44		77		
IDLE (with key pressed)	146		156
REBOOT SEQUENCE		120-150	120-150

SRAM write			143		156		1
SRAM read			142		155		1

CF write			148		156		2
CF read			144		156		2

SRAM->CF			149		154		1
CF->SRAM			141		154		1

internal->internal		142		150		3

IDLE (with no key pressed)	43		153		4
IDLE (with key pressed)	148		153		4


NOTES:

1. 174K file used
2. 1091K file used
3. files <100K used; both ROM->RAM and RAM->RAM tried, no apparent speed
difference
4. BAREST environment (PC booted with *no* autoexec.bat & config.sys in
ramdrive)
5. 5.0mA when CF card is removed! (No difference when SRAM card is removed.)

- all current measurements shown in mA
- all testing done with CPU running at 10MHz, using a regulated 6V pwr supply
- "LP" stands for Low-power(drain) mode - aka battery saver mode
- some of my results varied a little when repeated though thankfully not
much (probable causes include electrical contact issues due to awkward
setup, low-ish refresh rate of digital multimeter)
- SRAM is a 512KB battery-backed PRETEC brand SRAM card (as A: drive)
- CF is a 32MB Sandisk Compact Flash card (used with CF->PCMCIA adaptor as
B: drive)
- no black lines observed on the screen during reads/writes (that Christian
reports on his 95LX)
- obviously the bigger the file copied the better for measurement purposes
(ie taking at least a couple of seconds) and whilst I was constrained
somewhat by the media limitations (apart from the CF!) the vast majority of
transfers did range from 2-5 seconds which seemed to provide reasonable
figures 

Anyway, hope this is of some use!

Cheers,
Chris

At 12:51 06/02/2002 +0100, you wrote:
>Hi all,
>
>> From: FELIQUE CHRISTIAN <Christian.Felique@xxxxxxxxxx>
>
>reported the following with regard to his HP95LX --- maybe this is of
>some interest to you, or maybe you could help out with some of his
>questions:
>
>> I read about your CF experiment for the Sharp PC3000, and was keen to
try it on
>> my HP95LX. This is what my experience is with a Sandisk CF 32Mb card:
>> 
>> (1) In the HP95LX the CF still draws current even when it is turned off.
>> (2) When reading/writing to the card annoying black lines appear on the
screen.
>> 
>> (1) I solved this by cutting the Vcc line inside the PCMCIA to CF
>>     adapter, on the PCMCIA side of the adapter. Note that there are
>>     three voltage lines on a PCMCIA connector: Vpp1,Vpp2,Vcc. Vpp1
>>     and Vpp2 are (at least I think so) connected to the Vcc of the
>>     CF slot. The CF slot only has Vcc, and no Vpp1 and Vpp2. I think
>>     that Vcc on the PCMCIA connector is always powered, and Vpp1 and
>>     Vpp1 is only powered when reading, writing to the card.  Anyway,
>>     the CF card still works, and the card doesn't draw current
>>     anymore when my 95LX is turned off.
>> 
>> If you experience the same problem on your Sharp, then this might be a
solution
>> for you too. 
>> 
>> (2) The reason for this problem is the fact that the CF drains a lot of
current when
>> reading/writing. The LCD screen is connected to the same 5V power supply
as the PCMCIA slot.
>> That explains the black lines.
>> 
>> My questions:
>> 
>> Do you know how much current a CF drains when reading/writing ?  Do
>> you experience the same problems on your Sharp PC3100 ?  Are there
>> members of your mailing list that experienced this problems, and/or
>> found any solution for it. Maybe other soldering/cutting lines/CF
>> adapter modifications would solve this problem ? Any advise is
>> welcome.
>> 
>> Thank You
>> 
>> Best Regards,
>> 
>> Christian Felique
>> 
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