HP-15C

from Wikipedia, the free encyclopedia
Except for the ON key and the two shift keys themselves, all keys have three functions. The yellow and blue shift keys - pressed in front of the actual function key - are used to select the function that is to be called up when the function key is pressed.

The HP-15C was a programmable pocket calculator from Hewlett-Packard and the top model in the “Voyager” series . In addition to the functions of the HP-11C , it offers zero point determination , numerical integration , arithmetic with complex numbers and extensive matrix functions , additional flags and other comparison functions. It was the successor to the successful HP-34C and significantly expanded its range of functions. The production period was from 1982 to 1989. Due to numerous customer inquiries, HP offered a new edition under the name "Limited Edition" that was largely identical to the original in terms of appearance and function, which was quickly sold out.

properties

The UPN- operated calculator, like the HP-11C, has a complete set of mathematical and scientific functions with ten-digit accuracy, including hyperbola and combinatorial functions, statistics and regression, as well as a pseudo-random number generator. Compared to the HP-41 , on the other hand, there is no sign and a modulo function for determining the sign or division remainder , as well as the logarithm and exponential functions with higher accuracy for arguments close to 1 or 0.

Back with tables and instructions for angle and unit conversions

The matrix functions for up to five matrices, which were all elegantly embedded in the UPN logic, were a complete novelty. References (“descriptors”, A – E possible) from matrices could be stored as objects in the stack like real numbers. The built-in algorithms included the usual matrix operations (arithmetic, transposition, determinants, solving linear systems of equations, etc.). The inverse of a real matrix could be calculated directly up to dimensions 8 × 8. In addition, matrices of complex numbers were also supported, with somewhat restricted arithmetic operations. Saving and retrieving the matrix elements was supported by automatic functions that used two memories (0 and 1) to address the row and column numbers, so that matrices could also be entered and edited comfortably with the single-line numeric display. The automatic index management also made it possible to exit a loop after processing a matrix, see application example below.

For the calculation with complex numbers - which, like matrix operations, was already available on earlier models through skillful programming with restrictions - a second stack could be set up, which accommodated the imaginary elements and allowed the calculation as with real numbers, with exactly the same use all stack registers including LASTX. This resulted in extensive application possibilities, especially in electrical engineering, which were explained in detail in the manual. In the memory, complex numbers occupy a register each for the real and the imaginary part, which must be stored and recalled separately.

The user can divide the memory area between data and program memory; the latter is managed dynamically in order to use the higher functions (solver, integration function and matrices). A quadruple assignment of the keys could be avoided by the fact that some functions require an argument, e.g. B. g Test 2 for the comparison x <0. However, this required that some of the functions occupy two bytes of the program memory (such as the flag, solver and matrix functions, most loop control commands and some of the memory arithmetic), which was done until then was only the case with the HP-41. The two-byte commands also made it possible to extend the memory arithmetic to the recall of arguments (commands RCL +, RCL-, RCL *, RCL :), which is also an innovation and was only implemented again in the HP-42S and HP-32S . The result is that operations on X are possible without affecting other stack registers, and therefore one variable or one more argument can be kept in the stack.

The memory of the HP-15C comprises 12288 (12 Ki) words of ROM of 10 bits each and 82 register RAM of 7 bytes each. Of these, 67 registers are available to the user and can be configured between up to 67 data registers or up to 448 program bytes (with three remaining data registers I, 0 and 1). The registers assigned to the program memory but still free are also used by the matrix elements and solver and integration routines and for the elements of the complex stack and are dynamically released again.

As a supplement to the 15C, HP offered the "Advanced Functions Handbook", which explained the areas of solver, integration, complex arithmetic, matrix calculations and numerical accuracy using numerous examples and a comprehensive mathematical background.

The HP-15C was priced at US $ 135 when it was released, and US $ 80 in 1989.

Initiative and "Limited Edition"

Replica of the HP-15C as DM-15 from Swiss Micros in credit card format (88 × 59 × 7 mm³)

Although it has not been in production for a long time, the HP-15C continues to enjoy great popularity, which is reflected in high prices on the used market. This led u. a. to the fact that an initiative calls on HP to bring the computer back into production. Similar wishes are to provide a successor to the HP-32SII with the design of the HP-15C and a two-line display. In late summer 2011, HP surprisingly announced that it would be releasing the HP-15C in a limited edition. The design is strictly based on the original from 1981. The computer has the same functionality and capacity as the original, but is similar to other models with a new interior and achieves a significantly higher speed. The set number of the "Limited Edition" was quickly sold out, and this model is only available on the used market.

Swiss Micros offers two replicas which, according to the manufacturer, are based on the same code and emulate the original microprocessor (NUT) on an ARM. The full functionality should be available at 30 times the speed.

Application example

The following program calculates the trace (sum of the diagonal elements) of a square matrix whose descriptor is passed in I. The contents of Z and T are preserved. There is no error checking. The routine occupies 14 bytes (the two matrix operations are two-byte commands, but ISG on memory 0 is not.)

step Key code command comment
000-
001- 42.21.14 LBL D Label for the entry
002- 42.16. 1 MATRIX 1 positions row and column index to 1
003- 0 0 Beginning of addition
004- 36 ENTER duplicate the first summand
005- 44 0 STO 0 Correct line index
006- 42.21. 8th LBL 8 Loop for the sum calculation
007- 40 + Summation
008- 42. 6. 0 ISG 0 Increment row index to get only diagonal elements. Remove this command and STO 0 to add up all elements
009 and 45 24 USER RCL (i) Recall matrix element, automatically increment indices
010- 22 8 GTO 8 back to the beginning of the loop, if not the last element
011- 40 + add the last diagonal element
012- 43 32 RTN Return

Technical specifications

  • Classification: Scientific Calculator
  • CPU : CMOS HP SOS
  • FPU : none - BCD arithmetic
  • ROM : 12 KiW ROM of 10 bits each
  • RAM : 82 registers (574 bytes)
  • Keys: 39, two of which are shift keys
  • Display: Monochrome LC display with 10-digit seven-segment display
  • Batteries: 3 type "LR44" or similar.
  • Interfaces / peripherals: none
  • Dimensions: length 7.9 cm, width 12.8 cm, height 1.5 cm
  • Introduction: July 1, 1982 / discontinuation: 1989
  • Price at that time:
    • 1982: US $ 135, then around DM 450 (taking into account the change in purchasing power , the comparable euro price would be around EUR 440 today)

High demand for used equipment

Because of its high performance, the HP-15C is a very popular used device and regularly fetched prices well over 100 euros, which is unusual for pocket calculators.

Individual evidence

  1. ^ Hewlett-Packard Company (Ed.): HP-15C Advanced Functions Handbook . Corvallis, Oregon, USA August 1, 1982 (HP-Part Number 00015-90011; still available from hpmuseum.org ).
  2. ↑ http://www.hp15c.org/
  3. ↑ http://www.vcalc.net/hp.htm
  4. ↑ HP 15c Limited Edition Scientific Calculator .

literature

  • Eric A. Evett, Paul J. McClellan, Joseph P. Tanzini: "Scientific Pocket Calculator Extends Range of Built-in Functions", Hewlett-Packard Journal , May 1983, pp. 25-35 ( PDF; 9.6 MB ).

Web links

General links

Commons : HP-15C  - collection of images, videos and audio files

Replicas

Emulators

Individuals as well as companies offer emulators for the HP-15C and HP-12C (for Microsoft Windows , PalmPilots , PDAs and smartphones such as the iPhone ).