Programming the HP35s

Programs can be used for repetitive calculations - calculations that may involve more input or output control and intricate logic. You can use the hp 35s to enter a program which will allow the repetition of operations and calculations in a precise manner desired.

To enter a program into hp35s memory

Press {LeftShift}, then {PRGM} to activate Program-entry mode.

Press {LeftShift}, then {GTO}, {.}, then {.} to display PRGM TOP. This sets the program pointer to a known spot, before any other programs. As the program lines are entered, they are inserted before all other program lines. If other programs that might be needed in memory are not needed, clear program memory by pressing {LeftShift}, {CLEAR}, then {PGM}. To confirm that all programs are deleted, press Y after the message ‘CL PGMS? Y N’.

Give the program a label–a single letter, A through Z. Press {LeftShift}, then LBL, then letter. Choose a letter that will indicate the nature of the program, such as ’A’ for ‘area’. If the message ‘DUPLICAT.LBL’ is displayed, use a different letter. The existing program can be cleared instead–press {LeftShift}, MEM, then PGM, use {LeftShift}, then cursor-up or {LeftShift}, then cursor-down to find the label, and press {LeftShift}, then {CLEAR}, and {C}.

To record calculator operations as program instructions, use the same keys that would be pressed to perform operations manually. Remember that many functions do not appear on the keyboard, but must be accessed using menus. To enter an equation in a program line, see the instructions below.

End the program with a return instruction, which sets the program pointer back to PRGM TOP after the program runs. Press {RS}, then {RTN}.

Press C (or {LeftShift}, then {PRGM}) to cancel program entry.

Numbers in program lines are stored precisely as entered, and they are displayed using ALL or SCI format. (If a long number is shortened in the display, press {RS}, then SHOW to view all digits.)

To enter an equation in a hp35s program line

Press {RS}, then {EQN} to activate Equation-entry mode. The EQN annunciator turns on.

Enter the equation similar to entering an equation in the equation list. Use {LeftShift}, then {CLEAR} to correct errors while typing.

Press ENTER to terminate the equation and display its left end. (The equation does not become part of the equation list.)

After the equation has been entered, press RS, then SHOW to see its checksum and length. Hold the SHOW key to keep values in the display.

Use SUM+ and SQx to scroll the display. Press RS, then SCRL to turn off scroll and use the top-row keys to enter program instructions.

Keys that clear hp35s program entry

Note these special conditions during program entry:

{C} always cancels program entry. It never clears a number to zero.

If the program line does not contain an equation, {LeftShift}, then CLEAR deletes the current program line. It backspaces if a digit is being entered (’_’ cursor present).

If the program line contains an equation, {LeftShift}, then CLEAR begins editing the equation. It deletes the rightmost function or variable if an equation is being entered. {LeftShift}, CLEAR, then EQN deletes a program line if it does not contain an equation.

To program a function to clear the X-register, use {LeftShift}, {CLEAR}, then select X.

Function names in programs

The name of a function that is used in a program line is not necessarily the same as the function’s name on the key, in its menu, or in the equation. The name that is used in a program is usually a fuller abbreviation than that which can fit on a key or in a menu. This fuller name appears briefly in the display whenever a function is executed - as long as the key is held down, the name is displayed.

Example of entering and running a simple program

To find the area of a circle with the radius of 5, use the formula A = pi r2m and press {5}, {LeftShift}, {x2} , {RS}, {pi}, then {x} to get the result for this circle: 78.5398.

To find the areas of many different circles, it is not necessary to repeat the given keystrokes each time (vary only the ‘5’ for the different radii). The repeatable keystrokes can be put into a program:

001 x2

002 pi

003 x

This very simple program assumes that the value for the radius is in the X-register (the display when the program starts to run. It computes the area and leaves it in the X-register. To enter this program into the program memory, do the following:

Try running this program to find the area of a circle with a radius of 5:

The above procedures are applicable for HP33s.