|MMC/SD card problems.|
Message #20 Posted by James M. Prange (Michigan) on 17 Oct 2007, 4:55 a.m.,
in response to message #19 by Chris McCormack
Well, of course it could be a hardware problem with the
calculator, but do try some other things first.
What if I can't get the calculator to see the SD card? I was able
to use the card to install the 2.09 update on an HP50g, but after
resetting the calculator, it won't see the card. If this is a
hardware problem in the calculator (instead of operator error) I'd
like to figure it out during the warranty period.
Do the card's contacts look clean and undamaged? Maybe try
cleaning and lightly burnishing them, with, for example, an "ink"
or "typewriter" eraser, just enough so that they look nice and
shiny. Be sure to dust off any "eraser crumbs" before trying to
use the card.
Can the card be read by a card reader on a PC? If not, then
obviously something's wrong with it; try formatting it.
Note that various disk testing utilities, such as Microsoft
ScanDisk and Norton Disk Doctor, can be used to test the card in a
Forgive me for asking about something so basic, but are you
certain that the card is properly inserted? Label side toward the
back of the calculator, and pushed in until it's almost flush with
I doubt that this would help, but maybe at least temporarily try a
fresh set of AAA cells? If it doesn't help, you can set them aside
for later use.
Did the problem start immediately after flashing the ROM to 2.09?
If that's the case, then perhaps the ROM didn't really get flashed
properly. Maybe try flashing it to 2.09 again. Of course, if it
won't recognize the card, then you'll have to use Conn4x to flash
it, which really isn't all that much more difficult. But to use
Conn4x, you'll have to be using an MS Windows OS.
I suppose that it's possible that RAM somehow got corrupted, and
that that's somehow causing the calculator to fail to recognize
the card. To check for this possibility, first do a RCLF and STO
the flag list to a global variable, then use the ARCHIVE command
to back up user memory to port 2, or use Conn4x's "Backup..."
function to back it up to a PC. If you have anything in port 0
(which I don't recommend when any other port is available), also
back this up to some safe place. After you're certain that the
home directory and anything in port 0 is safely backed up, do a
memory clear by holding down the ON, A, and F keys together, and
then releasing F, A, and ON in that order. This gets you to the
TTRM ("Try To Recover Memory?") display. Press NO to clear user
memory and port 0, and also to restore the RAM reserved for system
use to its default state. Now try the card. Later, recall the
backup object created by ARCHIVE to the stack, and do a RESTORE
command, then RCL your flag list, and do a STOF. If you had
anything in port 0, then decide what to do with it; preferably, it
should be stored in port 1 or 2.
It could be that the card's file system somehow got corrupted.
Maybe try formatting the card with the calculator: Hold down ON,
press and release F, and then release ON; this should give you a
self-tests display. With the card inserted, press the - key for
the CARD utilities. If you get a "PLEASE INSERT CARD" message,
then try formatting the card with a PC instead. If you get a
"1.TEST" "2.FORMAT" message, then the calculator has detected the
card; press the 2 key for the FORMAT utility, then press the 1 key
to actually start formatting. If the "WAITING......" message is
displayed for more than a few seconds, then try formatting the
card with a PC instead. Wait for the "FORMAT FINISH" message and
then press ENTER to exit to the card utility display. Now press
the 1 key to run a card test (which, if the card is good, will
return a "TEST OK" message, but apparently, a "TEST OK" message
doesn't necessarily mean that the card really is "good"; see
below), and then follow the prompts to back out and do a reboot.
And yes, I do realize that the filer includes a FORMAT operation
if a card is detected, but I've had occasions when that failed but
the self-test FORMAT operation worked. Maybe the filer's FORMAT
operation does only a "quick" format instead of a "full" format?
That's something that I've never checked on.
If the above doesn't work, then try formatting the card in a card
reader on a PC.
If you still can't get the card to work, then try a different
card; they're reasonably low-cost these days, and even the lowest
capacity cards ever made are plenty big enough for typical uses
with the calculator.
If a "known-good" card, correctly formatted to a FAT12, FAT16, or
FAT32 file system (especially if tested in a different 50g or a
49g+), won't work in the calculator after a memory clear, then I'd
conclude that the calculator very likely has a hardware problem.
For what it's worth, I was given a couple of Samsung 32MB RS-MMC
cards. If I insert either one of these cards with the calculator turned
off, then there's usually no apparent response to the ON key, and
no response to an ON&C or an ON&A&F either, even if I remove the
card and try again. A "paper-clip reset" to invoke a warmstart is
required to get it running again. The paper-clip reset also works
if the card is still inserted. If I do a warmstart with the card
inserted to get the calculator running, or I insert the card after
the calculator is already ON, then everything seems okay unless I
try to start the filer, in which case the calculator usually
"hangs" with the busy annunciator on, and won't respond to the
keyboard at all; another paper-clip reset is required to get it
running again. With the card inserted and the calculator running,
the card self-test usually returns "TEST OK", and the self-test's
FORMAT operation will usually format the card. These cards usually
seem to work okay with various card-readers on PCs. So there can
be "borderline" cards that sometimes seem to work okay in some
Formatting a card with a PC may (depending on your operating
system or formatting utility) give you more flexibility in how
it's formatted, such as file system type, cluster size, and so on.
If the calculator is turned on with a card inserted, then there
will be a delay (sometimes not really noticeable) before anything
appears in the display. Of course slower cards cause a longer
delay, but also, it seems that the larger the FATs are, or perhaps
the more clusters are in the file system (larger capacity or
smaller cluster size), the longer the delay is. If this delay
seems annoyingly long, then (for a card larger that 32MB) maybe
format it to a FAT16 file system instead of FAT32, which results
in smaller FATs and fewer (but larger) clusters. The trade-offs
are that larger clusters typically result in more slack space, the
root directory for FAT16 is limited to 512 entries (at most, when
only "short filenames" are used), and fewer files can be stored,
but these usually aren't significant problems; if you use the card
only for the calculator, then you'll probably never use up all of
the card's capacity or maximum number of files anyway, and having
many entries in the root directory can cause an annoying delay
when starting the filer.
If the filer takes an annoyingly long time to start, then make
some subdirectories and move your files from the root directory to
somewhere else in the directory "tree", or delete unwanted files
that have accumulated. The idea is to reduce the number of entries
in the root directory.
For those really "into" formatting and partitioning, the
calculator can use a card that has an MBR (Master Boot Record),
like a hard disk (cards are often supplied this way), but an MBR
isn't required on the card for it to be used with the calculator
(or a card reader); it can start out with just a "boot record"
(like an ordinary floppy disk, except that a FAT32 file system can
be used on larger cards). In the case of a card that has more than
one partition, the calculator can "see" only one partition.
Edited: 19 Oct 2007, 4:27 a.m.