HP HP-67

Card Reader Operations 273
4. The entire program is now recorded on the magnetic card, and
also remains loaded in program memory of the calculator. The
contents of the data storage registers and the stack of the
calculator remain unchanged.
When you pass an unprotected card through the card reader with the
W/PRGM-RUN switch set to W/PRGM, whatever program instruc-
tions or data previously recorded on the card are wiped out and re-
placed by the contents of the HP-67 calculator’s program memory.
Besides the actual program memory step numbers and instructions,
the HP-67 also records the following information on a program card
on both the first pass and the second pass through the card reader:
The fact that a program (not data) is being recorded.
. The fact that this is side 1 (or side 2).
. Whether or not two passes are required.
Current status of flags FO, F1, F2, and F3 within the calculator.
Current status of trigonometric mode (i.e., DEG, RAD, or
GRD) within the calculator.
@R
e
N
N
. Current display format of the calculator.
7. A checksum (a code to verify that the program is complete
when it is reloaded).
All of this information is later read by the card reader when the
program is reloaded back into the calculator.
If any of the required information or program memory steps are not
recorded during a read, the HP-67 display will show
to indicate that the recording of the card was not complete. Clear the
error by pressing any key (the key function is not executed), then pass
the same side of the card through the card reader again.
Reloading a Recorded Program from a Card
Once a program has been recorded on a magnetic card, you can reload
it into the calculator any number of times. The procedure for reloading
a program from a magnetic card is the same as that for loading a
prerecorded program from a magnetic card into the calculator (see
page 124).