National Semiconductor SC / MP

from Wikipedia, the free encyclopedia
Chip photo of the PMOS SC / MP (ISP-8A / 500)

The SC / MP was obtained from National Semiconductor Corporation, Santa Clara, CA / USA ( www.national.com ) the mid-1970s as one of the first commercial 8-bit - microprocessors manufactured and marketed successfully. The processor name SC / MP (pronunciation: "skemp", English nickname "Scamp") is an acronym and stands for "Simple Cost-effective Micro Processor".

Single board computer

DIY computer from ELEKTOR (1977) by Jörg Behrens

One of the first do-it-yourself computers was published by Elektor- Verlag in June 1977 (G 3078EX) based on the SC / MP (initially type I, but quickly becoming type II). Another kit was launched on the market in 1978 by the electronics manufacturer and teaching material supplier Christiani Verlag from Konstanz as the SC / MP teaching computer. On the basis of Type III, another educational computer kit from Philips , later Schuco, was brought onto the market in 1983 .

Technical specifications

SC / MP ISP-8A / 500D in 40-pin ceramic - DIP housing
  • Technology: PMOS , NMOS
  • Number of transistors: several thousand
  • Clock frequency: traditionally 1 MHz
  • Clock cycles per command: 5 to 22
  • Address space: 64  KByte
  • Address bus width: 16 bit (12 + 4 bit)
  • Data bus width: 8 bits
  • Interrupts: multiple IR
  • Orders: 43
  • Addressing modes: several
  • Register: usually 8-bit and a.
    • Accumulator (AC),
    • Program counter / pointer register (PTR0)
    • Pointer register (PTR1, PTR2, PTR3),
    • Extension register (E),
    • Status Register (SR)
  • Monitor software: Elbug
  • Periphery: cassette interface

Periphery

  • Cassette interface
  • Sound interface
  • Prom Programmer
  • 8255 parallel IO interface
  • Metal paper printer
  • Number cruncher

Programs for the SC / MP

  • "Elbug" monitor software
  • Digital clock
  • Mastermind
  • Ram diagnosis
  • Lunar lander (speed and impact on the moon are reproduced via loudspeakers)
  • Battleship
  • Disassembler
  • Keyplay
  • Runtext
  • Tracer
  • NCU

Variants of the SC / MP

The following types of SC / MP processor were offered:

  • ISP-8A / 500D, SC / MP Type I in PMOS technology, two operating voltages (+5 V, −7 V)
  • ISP-8A / 600 (INS8060), so-called SC / MP II in NMOS technology, with higher clock frequency, one operating voltage (+5 V)
  • INS807x, so-called SC / MP III, NMOS technology, with modified instruction set and optional on-chip ROM (8073: with 2.5K Tiny BASIC)

The processor was offered in both 40-pin plastic DIP and ceramic DIP packages.

literature

SC / MP Technical Description. (pdf) No. 4200079A. National Semiconductor Corporation January 1976, archived from the original February 11, 2011 ; accessed on December 26, 2015 .

Web links