TUTORIAL 6: Interfacing with external devices
The HP48 has a distinctive advantage over many other calculators with
its connectivity to printers, PCs, total stations and other calculators.
Connectivity can be via Infra-red (IR) or via a serial cable.
The IR can transmit across a small-size room, however can only receive
at a range of about 6 inches ( a US college stipulation ).
Setting input/output parameters
Press [L-S] [1] (I/O) |IOPAR|
This displays the current input-output parameters which must be
concordant with the other device.
The IR / WIRE (Serial cable) can be toggled by pressing the |IR| key
The default baud rate is 9600. To change the baud rate type the baud
rate onto the stack and press the |BAUD| key.
To upload a program that will be editable on a PC. Toggle the |ASCII|
key so that the ASCII is selected. Press 3 then |TRAN| so that
translate: 3 is displayed.
Printing to an infra-red printer
By pressing [L-S] [1] |PRINT| several print options are available.
To print the contents a variable (or program ) type the name of the
variable onto the stack between ' ' characters. Press |PRVAR|.
To print level one of the stack press |PRST|
To print the contents of the stack press |PRSTC|
To print the screen and display press |PRLCD|
These commands can also be included in a program, so that results can
be printed during program execution.
If the Printer is printing unusual characters check the print parameters
|PRTPA|. Either the delay is to quick (the HP48 is sending data faster
than the printer can receive) the default is 1.8, or the printer may be
an older model in which case press the |OLDPR| key to re-map the character set.
Creating a program on a PC
Creating a program on a PC is much quicker than on the calculator itself, due to
the inherent benefits of the QWERTY keyboard and editor functions (and speed)
There are a few differences between the appearance of a program on a PC
and on the HP48. Mainly due to a different character set on the keyboard.
All characters on the PC keyboard are interpreted as is in the HP48.
Where a character on the HP48 is non-existent on the PC keyboard the HP48
translate code has to be used.
The back-slash \ character on a PC created program is interpreted by the
HP48 as a translate code.
Common examples:
HP48 PC character
<< \<< \->
>> \>>
Theta \Gh
The User Guide (p.27-16) displays a full listing of the translate codes.
All PC created HP48 programs must have a header (the first line of a PC program)
, so that the HP can
interpret the program.
The most commonly used header is thus:
HP: T(3)A(D)F(.);
Examples of programs are located in sample program link
Using kermit
Kermit is a public domain interface program on the PC allowing uploading and
downloading of programs and data from the PC to such beasts as the HP48. Instructions
on the use of kermit are in the link kermit.htm
RAM cards
RAM cards are only usable on the expandable GX models and act as "detachable
hard drives" so to speak. The GX has two card slots. Card slot one is
for 32kB or 128kB cards. Card slot 2 can accomodate up to 2 MB Cards. These
cards are NOT CHEAP!
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Last Update: 18th March 2001
Richard Stanaway