Mobile Measurement
Applications
Services
For ELAN PCMCIA drives: http://www.pccard.co.uk/support/ptroubleshooting.php
CardBus is the 'next
generation' of PCMCIA. It is a multiplexed version of the PCI bus,
capable of DMA and 32 bit transfers. The CardBus is
backwards-compatible, so any card that complies to the PCMCIA standard
can be used in a CardBus drive. A card that's compliant to CardBus can
not
be used in a PCMCIA standard compliant drive. The card is coded
mechanically at the connector, a CardBus card can't be plugged into a
PCMCIA slot.
For example USB PCMCIA
controllers usually need a CardBus slot.
Question
What's a PCMCIA drive?
Answer
A PCMCIA drive is needed
to operate a PCMCIA card. It provides at least one slot where a PCMCIA
card is inserted.
The term 'PCMCIA drive' is a
bit confusing, because technically it is no drive! The first PCMCIA
cards that were available have been memory cards. They are formatted
like a floppy disk. For that reason, we think the term 'PCMCIA drive'
exists.
A more precise definition
is 'PCMCIA interface card' or 'PCI-PCMCIA bridge'. In fact, these
drives translate one bus system (usally ISA bus or PCI bus) to PCMCIA
or CardBus standard.
Today, lots of different
card types are available, beginning from memory cards to hard drives,
modem and network cards, sound cards, GPIB, data acquisition and so on.
Even cards exist that
'translate' a PCMCIA bus back to ISA. They are used for notebooks if an
additional 8 bit ISA slot is required.
For operating a 'PCMCIA
drive', the operating system must support it by providing a driver. The
function of this driver is well-defined in the PC-Card standard. This
software usually called 'CardServices'. If you want to use PCMCIA
cards, check if your operating system provides CardServices. This is
true for Microsoft® Windows® 95/98, and
Windows® 2000 and XP operating systems, current Linux and
current
Sun
Solaris versions. Microsoft Windows NT® provides limited Card
services that do not support plug and play. Cards must be inserted
before and must not be removed while the computer is turned on.
In case you can't find 'PCMCIA socket', the CardServices may be either not installed or disabled. Reboot the computer in Safe mode and look again. If they are disabled, enable them. If they are not present, reboot the computer again in normal mode and install from CD.
If you use a PCMCIA hard disk, the problem can be the resources of the 'standard IDE/ESDI hard disk controller'. It is installed while the disk is recognized, but sometimes there exists a resource conflict that is not detected by the operating system. Try the other 'Base settings' listed.
If you changed the driver for the PCMCIA drive, you may need to delete the entries made for recognized cards in the registry. They are shown under HKEY_LOCAL_MACHINE\Enum\PCMCIA. Delete the keys of the corresponding cards and plug them in again for the recognition process starts again.
Question
Does the PCDAQ driver
support sharable interrupts?
Answer
Yes, interrupt sharing is
supported. However if many devices share an interrupt the performance
can be degraded.
Question
My data acquisition card does not work. The Card check hangs about a
minute in the data capture check. The data capture fails. Card's
resources are OK. I am using a PCMCIA drive with a Ricoh controller
that's plugged into a PCI slot.
Answer
There are interrupt routing problems using Ricoh
controllers. The card can be accessed but all IRQs issued by the card
are not forwarded to the kernel driver. The problem was solved by
changing the IRQ manually in the Device Manager to another free IRQ. It
can take a few retries, because not every free IRQ works.
Question
I have a Litronic Argus 2500 PCMCIA drive and can't get it running.
Each time I plug in a card (a CF card will do) the computer freezes
totally until I eject the card.
Answer
Although it is said that this PCMCIA drive works with
standard Windows drivers we think this it not true. You may have
recognized a holo-sticker with a "ELAN technology license" label on the
PCB. We were successful in getting the drive working with a PSeries
5.00 driver from ELAN. The drive uses a Ricoh RL5C476II controller.
After installing the drive with the driver, on our system (Intel P4
2.4GHz / Intel 845G chipset) occurred an ACPI problem in that way that
the computer won't enter standby or hibernation mode. In fact it
couldn't be selected any more in the Power options.
Question
(applies to
ELAN AD125 series)
I want to take samples at
high speed on multiple channels. Why is there a limit much lower than
the maximum sample rate of the card?
Answer
The card's input
multiplexer chooses a channel out of 8 or 16 total input channels.
A few microseconds are
required for switching channels.. In case the sample rate is too high,
the multiplexer has not finished channel switching. If that happens,
input signals of two input channels are merged together. The limits
written in the manual ensure that that does not happen. From experience
the sample rate can be increased about 20% above the limit if only two
channels are used.
Question
I set the card to
differential input mode. At first the measured looks like right, then
the signal shifts toward the positive or negative maximum. Peaks become
cut off. Finally the signal disappears and there's a constant reading
at the limit of the input voltage range.
Answer
This effect can be caused
if the following assumptions are true: The ground level of the input
signal, relative to the cards ground, is undefined AND the impedance of
the signal is high.
There are leakage
currents in the nA area running through the input multiplexer. They
cause a shift of the potential difference card-to-signal towards the
limit. Seen from the A/D input, the signal shifts in direction of the
limits (i.e. +10V or -10V if +-10V range is set). While shifting out of
the limits, the signal becomes cut off. At the time all signal parts
lie out of the input voltage range, it is disappeared entirely.
How to overcome this
effect:
Connect a 100...1000 kOhm
between one of both signal inputs to the AGND pin. In general, such a
resistor will not influence the input signal.
Question
I am performing frequency measurements with the PCMCIA card. The measured
frequency is always off by a few hertz.
Answer
The card generates the
sample rate
with aid of a
divider and a 5MHz resonator-controlled oscillator. The source itself
has a
tolerance of +/- 0.5% (…and another +/- 0.5% if the full
temperature
range is
used).
Second the steps between to divider settings are relatively coarse at
high sample rates and very fine at low sample rates. To improve this
matter,
the card has the choice between two differently generated rates.
As a rule of thumb use “even” numbers like 100,
200,250 or 500. They repeat each decade so errors in timing caused by
this
effect can be avoided. However the initial tolerance of the 5MHz
oscillator
remains.