Pause in WP34s

[Dieter]

(11-25-2015 12:41 PM)ggauny@live.fr Wrote:  Assume in a program you put a PAUSE instruction to have time for enter a numeric value, if it is no value do this, if it is value do that...

Using PAUSE or PSE for this can only be done with a few calculators, for instance the HP67/97 and the HP41. In both cases checking for entry can be done by testing flag 3 resp. flag 22/23.

But this will not work with most other HP calculators. For instance the HP34C simply stops as soon as any key is pressed, and the 35s ignores keystrokes during PSE. So do others.

However, on the 34s keystrokes during a PSE statement are registered. They can be checked by using the KEY? test. There is a special section on input and output in the manual. Note that KEY? does not return a numeric value but the code of the key that has been pressed.

Here is an example:

Code:

CLX
INC X
PSE 30      // wait for up to 3 seconds, but continue as soon as a key has been pressed
KEY? X      // if a key has been pressed during the pause, put its code in X
BACK 003    // it NO key was pressed, jump back
RTN

Note that the step after KEY? is executed if no (!) key has been pressed.

Run the program and see 1 ... 2 ... 3 ... Press a key, for instance ENTER, and see its keycode (here 31) returned by the program.

(11-25-2015 12:41 PM)ggauny@live.fr Wrote:  I've try with ENTRY?, no run too.

ENTRY? is similar (but not identical) to testing flag 3 or 22/23 on the 67/97/41. So you can check whether something has been entered, e.g. after a PROMPT where the program stopped.

Another example:

Code:

CLalpha
alpha"R=?"
PROMPT      // prompt for radius
ENTRY?      // if something has been entered
SKIP 001    // jump to calculation
BACK 005    // else prompt again
x²
Pi
x           // calculate area of circle
CLalpha
alpha"ARE"
alpha"A="
VWalpha+ X  // and display output
RTN

HTH,

Dieter