HP-42S
The HP-42S RPN Scientific is a programmable RPN Scientific hand held calculator introduced by Hewlett-Packard in 1988. It is a popular calculator designed for science and engineering students.
Overview
Perhaps the HP-42S was to be released as a replacement for the aging HP-41 series as it is designed to be compatible with all programs written for the HP-41. Since it lacked expandability, and lacked any real I/O ability, both key features of the HP-41 series, it was marketed as an HP-15C replacement.The 42S, however, has a much smaller form factor than the 41, and features many more built-in functions, such as a matrix editor, complex number support, an equation solver, user-defined menus, and basic graphing capabilities. Additionally, it features a two-line dot matrix display, which made stack manipulation easier to understand.
Production of the 42S ended in 1995.
Specifications
- Series: Pioneer
- Code Name: Davinci
- Introduction: 1988-10-31
- 64 KB of ROM
- 8 KB of RAM
- Functions: Over 350
- Expandability: Officially no other than IR printing
- Peripherals: HP 82240A infrared printer
Features
- All basic scientific functions
- Statistics
- Probability
- Equation solver that can solve for any variable in an equation
- Numerical integration for calculating definite integrals
- Matrix operations
- Complex numbers
- Vector functions
- Named variables, registers and binary flags
- Graphic display with graphics functions and adjustable contrast
- Menus with submenus and mode settings that use the bottom line of the display to label the top row of keys
- Sound
- Base conversion, integer arithmetic and binary and logic manipulation of numbers in binary, octal, decimal and hexadecimal systems
- Catalogs for reviewing and using items stored in memory
- Programmability
- The ability to run programs written for the HP-41C series of calculators
Programming
All programs are stored in one continuous program space, and may be created and edited by switching to programming mode, using the key.
Subroutines are enclosed in /Label and /Return. Keystrokes are enclosed between and or.
In a running program, a label causes program execution to branch to the specified label and continue running at that line. Executing a GTO instruction from the keyboard moves the program pointer to the corresponding label. No program lines are executed.
is used in much the same way with one important difference: after an instruction has transferred execution to the specified label, the next RTN or END instruction causes the program to branch back to the instruction that immediately follows the XEQ instruction. Programs/Subroutines can also be executed with the help label key.
The important difference between the and is that executes the label and returns to previous subroutine and continues execution from the line following,whereas branches to the label specified and doesn't return.
packs the current subroutines and moves to new program space.nnnn can be used to reach a particular line of program.
Programming examples
A simple program to calculate area of circle| Step | Instruction | Comment |
| 00 | - | |
| 01 | Start of program "AREA" | |
| 02 | Prompts for Value of R and stores it in R | |
| 03 | Squares the value in X register | |
| 04 | Puts π on the stack | |
| 05 | Multiplies values in X and Y register | |
| or | Returns control to either the user or to a calling program. | - |
Program instructions like,, halt the program execution,which can be continued by pressing.
is used to view contents of a register,For example R in the above example.
Using Integral and Equation Solver
It is necessary to write a program or subroutine that evaluates f for the function which needs to be solved or integrated.Variables used in program should be declared using
Here is a sample program to solve the equation °F = + 32
| Step | Instruction | Comment |
| 00 | - | |
| 01 | Start of program "TEMP" | |
| 02 | Declares F as a variable for solver | |
| 03 | Declares C as a variable for solver | |
| 04 | Recall F | |
| 05 | ||
| 06 | ||
| 07 | - | |
| 08 | Recall C | |
| 09 | ||
| 10 | - | |
| 11 | - | |
| 12 | - | |
| or | Returns control to either the user or to a calling program. | - |
After, accessing the solver using , select program.
In a similar way, expressions can be integrated. After selecting the variable of integration, enter the lower limit and then press on, similarly input and .
Emulators
HP 42s can be accessed through Android Emulators like Emu42 and Free42.Image:Hp30bwp34s.jpg|200px|thumb|WP 34s