The Sharp PC-1403 was a small

scientific calculator A scientific calculator is an electronic calculator, either desktop or handheld, designed to perform mathematical operations. They have completely replaced slide rules and are used in both educational and professional settings. In some area ...

and pocket computer manufactured by Sharp. It was the successor of the

Sharp PC-1401 The Sharp PC-1401 is a small pocket computer manufactured by Sharp. It was introduced in 1983 and is one of the first combinations of scientific calculator and portable computer with BASIC interpreter/bytecode compiler. The PC-1402 has the same fe ...

, and had better display, more RAM and better system software.

Technical specifications

* CPU: Hitachi SC61860 (8-bit CMOS) 768 kHz * Memory: 8 KB RAM (6863 bytes available), 72 KB ROM; 32 KB RAM in PC-1403H model * Display: Monochrome

LCD A liquid-crystal display (LCD) is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers. Liquid crystals do not emit light directly but in ...

1 line with 24 5×7 characters * Power: 6 V DC - 2× CR2032, 0.03 W * Connector (11 pins) for external devices * Integrated speaker (4 kHz beep only) * Contrast adjustment wheel * Software: Simple BASIC interpreter; calculator mode * Matrix calculations Manufacturing started in 1986. It is possible to convert the 1403 to a 1403H by removing the 8 K RAM and soldering in a 32 K RAM. An inverter IC is needed for this, too.

Calculator

Calculations could be performed in two modes ''CAL'' and ''RUN''. In the former, the PC-1403 would behave like a normal scientific calculator at the time with formulas entered in algebraic logic. In ''RUN'' mode, BASIC statements could be entered for immediate execution and print out. The latter was similar to the

Direct algebraic logic There are various ways in which calculators interpret keystrokes. These can be categorized into two main types: * On a single-step or immediate-execution calculator, the user presses a key for each operation, calculating all the intermediate resul ...

employed by modern calculators.

Programming

The programming model employed was

unstructured BASIC BASIC (Beginners' All-purpose Symbolic Instruction Code) is a family of general-purpose, high-level programming languages designed for ease of use. The original version was created by John G. Kemeny and Thomas E. Kurtz at Dartmouth College in ...

for which the PC-1403 distinguished between ''RUN'' and ''PRO'' mode. The later being used to enter and edit program and the former being used to execute them.

Programming example

Here is a sample program that computes the factorial of an integer number from 0 to 69. It can be called by entering a number or an expression followed by pressing DEF F (in run mode). 10 "F" AREAD N ''allows to start the program with DEF F 20 F=1 ''Set start value of F to 1 30 FOR I=1 TO N ''counts I from 1 to N 40 F=F*I ''calculates F=F*I 50 NEXT I ''repeats loop from line 40 60 PRINT STR$ N+"!=";F ''print result - i.e. 5!=120. 70 END ''end of program

Machine language programming

It is possible to write machine language programs into memory using the POKE command and starting them with the CALL command.

References