1. About this User Manual
This user manual refers to special features of DM41X. PDF version of this manual is available at
https://www.swissmicros.com/dm41x/doc/dm41x_user_manual.pdf
Search internet for documentation of original HP-41C calculator and related modules and utilities.
Especially useful is
site, where manuals could be viewed on-line and/or downloaded
complete DVD for off-line access.
Other sites with manuals:
•
https://archived.hpcalc.org/greendyk/
•
https://qrg41.fjk.ch/index.html
2. General Information
2.1. CPU Speed
CPU speed is 24MHz when running on battery (due to limited battery current) and increases to
80MHz when the USB cable is connected.
2.2. IR Printing
Calculator contains IR output and can print on HP 82240A/B infrared printer using emulation
through 'Thermal Printer' module (which is by default bundled in firmware).
Note that 'Thermal Printer' module has to be
plugged-in
first. See
for more
information.
2.3. Internal FAT disk
The calculator has 6MB of internal flash storage formatted as a FAT filesystem that is used for
loading/saving programs and for backing up calculator state. It is accessible as USB disk when
activated via the menu 'File > Activate USB Disk >'.
Internal flash has limited amount of write cycles. While the lifetime with ordinary
usage could be dozens of years, an excessive number of writes will wear the flash
memory much quicker.
Worst case scenario, you would have to replace the flash chip, which is worth less
than $1. If needed, SwissMicros will replace the chip at no cost, but shipping costs
must be covered by the customer.
The datasheet mentions a minimum of 100,000 write cycles, which sounds like a
lot, but any change in the filesystem means overwriting at least part of the file
allocation table, which is stored in a static location.
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