HP HP-65 - Page 79

Identifying Stops
Blinking Display Stops. Errors that cause a blinking zero dis-
play, if executed in a program, also stop the program. You can
identify the stop by switching momentarily to W/PRGM to see
the code of the offending operation.
Normal Stops. To confirm that a program stops normally (i.e.,
via a or &) switch momentarily to W/PRGM position
and observe the displayed code. It should be 24 or 84.
Accidental Stops. Remember, that pressing any key will stop a
program. Be careful to avoid pressure on the keyboard during
program operation.
Cued Stops. If memory space permits, it is sometimes helpful
to put a familiar number into the X register before stopping for
data. Thus when the program stops, the displayed number identi-
fies the desired input. For example if your program requires 8
stops for input, it is very helpful to have the numbers 1, . .., 8
appear so you know which input is needed.
If a cue number is created as a program step immediately pre-
ceding the [, it is not lifted into the stack and the number
is overwritten by the data you key in. (Cue numbers generated
by other means will be lifted.)
Concerning W/PRGM Mode Display
Another feature of the W/PRGM display is that it allows you
to see the last key pressed in a series of manual operations (ex-
cept program operations). For example, in RUN mode you intend
to key in
4.032 [+
when the phone rings. After talking on the phone you can’t re-
member whether or not you pressed the + key. Switch to
W/PRGM, you will see 61 if you pressed [+ .
If you have been calculating manually, and then wish to display
a program, pressing will resume the program memory dis-
play.