Casio FX-502P series
Encyclopedia
The FX-501P and FX-502P were programmable calculator
s, manufactured by CASIO
from 1978. They were the predecessors of the Casio FX-601P and Casio FX-602P.
as was state of the art at the time.
The FX-501P could store 128 steps, with 11 memory registers. The FX-502P had double capacity with 256 steps and 22 memory registers.
Conditional and Unconditional jumps as well as subroutines where supported. The FX-502P series supported 10 labels for programs and subroutines called P0 .. P9. Each program or subroutine could have up to 10 local labels called LBL0 .. LBL9 for jumps and branches.
The FX-501P and FX-502P supported indirect addressing both for memory access and jumps and therefore the programming model could be considered Turing complete
.
Since the FX-501P and FX-502P only employed a Seven-segment display
each program step was represented by a special 2 digit codes made op of the digits 0 .. 9 and the character C, E, F and P. The Calculator came with a special overlay so the user need not memorise the mapping between code and actual command.
Key-code Display-code Comment
P0 P0 You'll call the program with the P0 key
Min 0 C6 00 stores the value in register M0
1 01 starts with 1
LBL 0 F0 00 label for the loop
* E1 multiply
MR 0 C7 00 by n
DSZ GOTO 0 FF 01 F1 00 decrements register M0 and back to LBL0 until M0=0
= E5 end of loop, the machine has calculated 1*n*(n-1)*...2*1=n!
to store program and data to Compact Cassette
using the Kansas City standard
. The FA-1 also enabled the calculators to generate musical notes.
Programmable calculator
Programmable calculators are calculators that can automatically carry out a sequence of operations under control of a stored program, much like a computer. The first programmable calculators such as the IBM CPC used punched cards or other media for program storage...
s, manufactured by CASIO
Casio
is a multinational electronic devices manufacturing company founded in 1946, with its headquarters in Shibuya, Tokyo, Japan. Casio is best known for its electronic products, such as calculators, audio equipment, PDAs, cameras, musical instruments, and watches...
from 1978. They were the predecessors of the Casio FX-601P and Casio FX-602P.
Arithmetic
The FX-502P series use the algebraic logicDirect Algebraic Logic
There are various ways in which a calculator might interpret key strokes.One can categorize calculators into two main types: 1) single-step or immediate execution calculators and 2) expression or formula calculators....
as was state of the art at the time.
Display
The FX-501P and FX-502P featured a single line 7-segment liquid crystal display with 10 digits as main display. An additional 3 digits 7-segment display used to display exponents and program steps when entering or debugging programs and 10 status indicators. The display was covered with a yellow filter, supposedly to prevent ultra-violet radiation damage.Programming
The programming model employed was key stroke programming by which each key pressed was recorded and later played back. On record multiple key presses where merged into in a single programming step. All operations fitted into one program step.The FX-501P could store 128 steps, with 11 memory registers. The FX-502P had double capacity with 256 steps and 22 memory registers.
Conditional and Unconditional jumps as well as subroutines where supported. The FX-502P series supported 10 labels for programs and subroutines called P0 .. P9. Each program or subroutine could have up to 10 local labels called LBL0 .. LBL9 for jumps and branches.
The FX-501P and FX-502P supported indirect addressing both for memory access and jumps and therefore the programming model could be considered Turing complete
Turing completeness
In computability theory, a system of data-manipulation rules is said to be Turing complete or computationally universal if and only if it can be used to simulate any single-taped Turing machine and thus in principle any computer. A classic example is the lambda calculus...
.
Since the FX-501P and FX-502P only employed a Seven-segment display
Seven-segment display
A seven-segment display , or seven-segment indicator, is a form of electronic display device for displaying decimal numerals that is an alternative to the more complex dot-matrix displays...
each program step was represented by a special 2 digit codes made op of the digits 0 .. 9 and the character C, E, F and P. The Calculator came with a special overlay so the user need not memorise the mapping between code and actual command.
Programming example
Here is a sample program that computes the factorial of an integer number from 2 to 69. For 5!, you'll type5 P0 and get the result, 120. The whole program is only 9 bytes long.Key-code Display-code Comment
P0 P0 You'll call the program with the P0 key
Min 0 C6 00 stores the value in register M0
1 01 starts with 1
LBL 0 F0 00 label for the loop
* E1 multiply
MR 0 C7 00 by n
DSZ GOTO 0 FF 01 F1 00 decrements register M0 and back to LBL0 until M0=0
= E5 end of loop, the machine has calculated 1*n*(n-1)*...2*1=n!
Interface
The FX-501P and FX-502P used the FA-1Casio FA-1
The FA-1 Interface was used the FX-502P and FX-602P series of programmable calculator to store programs and data register to Compact Cassette.-External links:* on shows the FA-1 interface....
to store program and data to Compact Cassette
Compact Cassette
The Compact Cassette, often referred to as audio cassette, cassette tape, cassette, or simply tape, is a magnetic tape sound recording format. It was designed originally for dictation, but improvements in fidelity led the Compact Cassette to supplant the Stereo 8-track cartridge and reel-to-reel...
using the Kansas City standard
Kansas City standard
The Kansas City Standard , or Byte standard, is a digital data format for audio cassette drives. Byte magazine sponsored a symposium in November 1975 in Kansas City, Missouri to develop a standard for storage of digital computer data on inexpensive consumer quality cassettes, at a time when...
. The FA-1 also enabled the calculators to generate musical notes.
External links
- FX-501P and FX-502P on RS-Key maintained by Viktor Toth.
- casio fx-501p and casio fx-502p on Voidware