Intel MCS 4/40 description

From: "Intel MCS-40 User's Manual for Logic Designers", Nov 1974. (MCS-40 was Intel's description of the 4040 chip set.) I have an Intellec 4/40 system, details on this linked Web page.


• Complete hardware/software development system for the design and implementation of 4040 CPU based microcomputer systems.

• TTY interface, front panel designer’s console, and high speed paper tape reader interface, in conjunction with PROM resident system monitor provide complete program loading, punching, monitoring, interrogation, and alteration capabilities.

• Program RAM (4K 8 bit bytes) provides a program development medium which lends itself to rapid and facile program monitoring and alteration.

• Data RAM (320 4 bit bytes expandable to 2560 bytes) provides data storage capacity.

• Program PROM (expandable to 4K 8 bit bytes) in con- iunction with the resident PROM programmer provide capability of simulating final ROM resident program.

• PROM resident system monitor and RAM resident macro- assembler included in standard systems software.

• Includes such standard program development features as program single step, address search (and pass count), next instruction indication, program flow verification.

• I/0 expandable to 16 4 bit input ports and 48 4 bit output ports (all TTL compatible) allowing "hands-on" simulation of entire user system (processor and peripheral devices).

• RESET, STOP, INTERRUPT control signals available to user via back panel.

• Modular design with expansion capability provided for up to eleven optional or user designed modules.

[4040 chart]

The lntellec 4/MOD 40 (imm 4-44A) system is a complete, self-contained microcomputer development system designed specifically to support the development and implementation of 4040 CPU based microcomputer systems. Its modular design provides the flexibility to adapt to any size user system and the resident software greatly facilitates program development.

The basic Intellec 4/MOD 40 system consists of a 4 microcomputer modules (CPU, RAM, MEMORY CONTROL, and PROM PROGRAMMER), power supplies, l/O connectors, console, and displays. The heart of the system is the imm 4-43 central processor module built around lntel’s high performance 4 bit 4040 CPU on a single chip. The imm 4-43 is a complete microcomputer system containing the system clock, 1K 8 bit bytes of PROM memory, 320 4bit bytes of data RAM memory, 3 4 bit input ports and 8 4 bit output ports. The imm 6-28 program RAM memory module contains a 4K x 8 memory array composed of Intel 2102 static random access memory elements. The imm 4-72 control module contains the circuitry required to interface the central processor module to the program RAM module. The imm 6-76 PROM programmer module provides the capability of programming Intel 1702A PROMs in coniunction with the front panel PROM socket and system monitor. All I/O ports are TTL compatible and accessible from the back panel 37 pin con- nectors. The front panel designer's console provides a means of monitoring and controlling system operation.

The modular design of the Intellec allows great design system flexibility. Program PROM can be expanded to 4K 8bit bytes using imm 6-26 or imm 4-22 optional modules. Data RAM can be expanded to 2560 4 bit 'bytes using imm 4-24 modules. I/O capability can be expanded to 16 4 bit input. and 48 4 bit output ports using optional imm 4-60 modules. The universal prototype card (imm 6-70) in coniunction with the eleven optional card sockets (which contain all essential system signals) provide the capability for interfacing custom designed modules.

The user RESET IN/OUT, STOP/STOP ACKNOWLEDGE, and INTERRUPT/INTERRUPT ACKNOWLEDGE control signals are all available at the back panel. Hence, the user can interrupt, halt, and reset the resident CPU via his own interface.

Program interrogation and alteration can be accomplished by using any desired combination of the front panel design- er's console, a teletype, the imm 4-90 high speed paper tape reader, and other Intellecm compatible peripherals. The front panel designer’s console provides the capability of manually writing data into memory and displaying memory contents, monitoring CPU bus contents during each processor subcycle, "freezing" system status after execution of a predefined instruction after a specified number of passes, single-stepping the program and verifying program flow..The teletype and reader serve as vehicles to input and output paper tapes and execute the system monitor.

Every Intellec® 4/MOD 40 system comes with two systems software products — the PROM resident system monitor and the RAM resident assembler. The assembler has a paper tape editor feature. The systems software is a powerful application program development tool.

The system monitor provides the capability of displaying and modifying memory contents, reading and punching object tapes, dynamically assigning system peripherals, programming and verifying PROMs, and performing functions which significantly reduce program debug and development time.

The Intellec 4/MOD 40 RAM resident assembler translates source code into object code which will execute the lntellec 4/MOD 40 or any MCS-40'Msystem. The assembler collects information'from the source program, builds an internal symbol table, outputs a listing of the assembled program including error messages, and punches an obiect program tape.


Word Size
Data: 4 bits
Instructions: 8 bits/16 bits

Memory Size
5K bytes expandable to 12K bytes (combination of PROM,
Data RAM, Program RAM) in three 4K byte memories selectable
for execution from the front panel.

Instruction Set
60; including conditionals, binary and decimal arithmetic,
and l/O

Machine Cycle Time

System Clock
Crystal-controlled at nominal 5.185 MHz

l/0 Channels
All ports are 4-line TTL
3 input ports expandable to 16
8 output ports expandable to 48

Available at back panel

Console Memory Access
Standard via control console

Memory Access Time
1 us with standard memory modules

Environmental Characteristics
Operating temperature: O°C to 55°C

Electrical Characteristics
DC power supplies: Vcc = 5V +/- 5%
Icc = 12A
VDD = -10V +/- 5%
IDD = l.8A
AC power supplies: Mod 40: 60 Hz, 115 VAC @ 200 W
Mod 40/220: 50 Hz, 230 VAQ @ 200 W

Physical Characteristics
Intellec 4/40: 7" >g 17 1/8" x 12 1/4" (table top only;
optional rack mount available)
Weight: 30 Ib. (13.61 kg.)

Optional Modules
Available for the lntellec 4/MOD 40:
imm 4-22 Instruction/Data Storage Module
imm 4-24 Data Storage Module
imm 4-60 Input/Output Module
imm 6-26 PROM Memory Module
RAM Memory Modules (Additional)
imm 6-36 Rack Mounting Kit
imm 6-70 Universal Prototype Module
imm 6-72 Module Extender

Equipment Supplied
Central Processor Module
RAM Memory Module
PROM Programmer Module
Memory Control Module
Chassis with Mother Board
Power Supplies
Control and Display Panel
Finished Cabinet
PROM Resident System Monitor
RAM Resident Assembler

Complete Hardware Software
Programmers Manual
Operators Manual
Hardware Reference Manual
Module Schematics


Programming for the MCS-40 microcomputer can be done easily and quickly using Inte|’s new cross macro assembler, MAC4. This powerful assembler translates three letter mnemonics representing each MCS-40 instruction into a numeric representation that may be loaded directly into an lntellec 4 development system or programmed to ROM. Advanced MAC4 features provide full macro capability and conditional assembly capability. All output is in hexadecimal for easy interpretation.

MAC4 is written in ANSI standard FORTRAN IV and is designed to run on any large scale computer system (32 bit word size or larger) with little or no modification. The FORTRAN source program for MAC4 is available on magnetic tape directly from Intel. In addition MAC4 may be used on either TYMSHARE, UNITED COMPUTING SYSTEMS, or GENERAL ELECTRIC worldwide timesharing services and may also be used on TIMESHARING LTD in Europe. Contact these services directly for further information.


[4040 library form] The MCS-40 User’s Library is a collection of programs written by users of the 4004 and 4040 CPU chips. These programs have been contributed to the user’s library for the benefit of all MCS-40 users. Intel will make source listings of all programs and detailed instructions on their use available to all members of the MCS-40 User's Library. To become a member simply: 1.Submit a program to the library with detailed documentation and a completed user’s library submittal form, or 2. Pay a yearly membership fee.

For more information,contact your local Intel representative. Some of the current programs in the library includes:

• Cross Assembler for PDP 8
• BNPF Tape Generator for PDP 8
• MCS-40 Simulator for PDP 8
• Chebyshev Approximation Functions for
    64 bit Addition, Subtraction, Multiplication, Division
• Parity Checker/Generator 
• Parity Generator, ASCII Character
• ASCII to EBCDIC Code Conversion
• Delay Subroutines
• Cross Assembler for NOVA
• Bit Manipulation Routine

(User's Library submittal forms are in back of manual.)

Contact information:
Herb Johnson
New Jersey, USA
To email @ me, see
see my ordering & contact Web page.

Copyright thiw Web page © 2012 Herb Johnson. However the content is from Intel's manual as noted. Intel may not own copyright on these materials, as they sold off much of their oldest processors lines long ago. - Herb