In 1976 Texas Instruments released LCM-1001, a 4-bit microprogrammer based on SPB0400 CPU. It was designes as a simple learning tool to study microcomputer operation and programing.
The SB0400 CPU was the first processor made using VLSI (Very Large Scale Integration) technology.
The microprogrammer could be expanded through the 40-pin socket with LCM-1002 Controller Module, LCM-1003 Memory Module and LCM-1004 Input/Output Module, which were sold separetly.
Here's the advertisement from the September 1976 issue of the "Byte" Magazine:
"New. The complete microprocessor learning system. Ready-to-use. Economical. User-paced.
Introducing three new add-ons for TFs basic Microprogrammer Learning Module.
Microprocessors. Now they're simpler to understand, easier to cope with, because of TI's complete new microprocessor learning system.
It's modular... consists of four, portable components: the basic
LCM 1001 Microprogrammer Learning-Module and three new add-ons: Controller, Memory, And Input/Output.
It's a down-to-fundamentals system for getting "hands on" experience with microprocessors. It focuses your attention on learning microprocessor concepts — not on individual products. You progress from module to module in a logical sequence. Each module is self-contained.
Complete and ready-to-use. No kits to assemble. Nothing to build. Each has its own battery/charger power system. Each has its own instruction manual.
This is the one you start with. The basic building block (LCM-1001). It demonstrates the most fundamental level of microprocessor operation: Single-clock-step microinstruction. It contains a 4-bit static parallel processor with manual switch inputs, VLED monitors, and pushbutton manual clock. A 40-pin
socket lets you link up with the controller. $149.95
Add the LCM-1002 Controller Module. Progress from micro to
macro level programming. Learn instruction set development and
microcomputer architecture. Use the Controller with RAM or addi-
tional program memory — 12 basic instructions are programmed into the PROM (which may be redefined). Using these, write your own programs. Or, expand the instruction set and customize the system to your needs using the blank locations you define yourself. $189.95
Add an LCM-1003 Memory Module to the Controller. Now you're
into fully automated digital system operation. The read/write memory is configured as a IK word by 12-bit structure, for both data and program storage. Switches are provided for manual loading. The memory automatically increments the address. This feature spares you the tedium of cycling the entire memory when loading or changing memory. $189.95
With the final LCM-1004 module, you're in contact with the outside world.
There are four 4-bit input ports and four 4-bit output ports with buffers for data transfer synchronization. Operate the ports independently, or in conjunction with each other. For example, two ports can recognize an 8-bit code approach. $109.95
This approach to microprocessor self-instruction is sensible and
economical — add another module when you're ready to learn more.
To order your Microprocessor Learning Modules, call your near-
est TI distributor."