Interpretingkeycodes - HP -11C Owner's Handbook Manual

Section 5: Programming Basics 81
When the calculator is in program mode, the number that you see
on the left side of the display indicates the line number in program
memory to which the calculator is set. Press CLEAR [PRGM],
then [A]—thefirst keystroke of the heat loss program (page
12)— and the display will change to:
001-42,21,11
-
o
Line Number —' L——- Keycode
The calculator is now set to line 001 of program memory, as
indicated by the 001 that you see on the left side of the display. The
other numbers in the display are keycodes for the keystrokes that
have been loaded into that line of program memory. Press 3. Your
display shows:
002- 3
N S
Line Number ——4 L Keycode
The 002 on the left side of the display indicates that you are now at
line two of the program.
Each line of program memory '"'remembers" a single program
instruction, whether that instruction consists of one, two, or three
keystrokes. Thus, one line of program memory might contain a
single-keystroke instruction like [CHS], while another line of
program memory could contain the three-keystroke instruction
6 (adds the number in the displayed X-register to the
number in Rg). The keystrokes in program instructions are
represented in the calculator by keycodes.
Interpreting Keycodes
Most keycodes for HP-11C key positions are determined by a
simple row/column matrix. The key rows are numbered 1 through
4. The key columns are numbered 1 through 10. (The tenth column
is represented in HP-11C keycodes as a 0, for example, "20"
represents row 2, column 10, and corresponds to the key. The
only key positions which do not conform to the matrix code are
functions assigned to the 0 through 9 digit keys. The codes for
functions on these keys are simply the single digit on the face of the
key.