User:Ttz642/MPT8080

Limrose MPT8080 Microprocessor Trainer
The Microprocessor trainer was designed specifically for training of students and engineers in the relatively new microprocessors of the 70's & 80's.

Initially an Intel 8080 & Motorola 6800 trainer were developed but due to some technical and operational issues the 6800 trainer was halted and development continued with the 8080.

The idea behind the MPT8080 is the ability of the user to enter simple programs, execute the code and observing whats happening on the address, data and control signals of the microprocessor.

An 8-bit input and output port allows code to interact with external stimulus. The I/O ports also have connectors allowing them to be connected to external signals (eg with the limrose patch kits) and control / monitor real circuitry.



MPT8080 Version 1
Originally designed by Dr Ravi Raizada, CEO of Limrose Electronics and first marketed in 1977.

8 binary switches and load button for data entry.

MPT8080 Version 2
In ~ 1980 it was an updated. From the user point of view it simply incorporated a 16 key hex keypad for data entry rather than 8 binary switches, but in fact >50% of the board/circuitry was re-designed.

What's Inside the MPT8080 Version 2
This is from memory, its been almost 30 years since I designed this and I no longer work for the company and don't have one to check (at the moment).

The major components being:

* 16 led's displaying the program counter * 8 led's displaying the data bus * 8 led's displaying the status signals of the 8080 * 8 led's displaying the contents of the output port * 20 key Keypad * 16 hex digits 0 .. 9 & A .. F * RESET - Reset * I - Interrupt * K - Clear current memory location * S - Step / Advance PC * MMLE / Run - Manual Memory Load and Examine / RUN - Set the operating mode to normal code execution or data entry * SI/SC - Single Instruction or Single Cycle for run mode, only relevant when in SSTP mode * SSTP / CONT - selects Single-Step or Continuous execution mode
 * LEDS:
 * Switches
 * 3 Control switches (bottom left)

* Intel 8080A microprocessor * 1K of ram, 2 * 2114 (1Kx4-bit ram) * Dallas / Nat Semi 20 key keyboard decoder * State machine created with 74 series TTL to control data entry and program execution
 * Major semiconductor components

Operating the MPT8080
To load a program put the MPT8080 in data entry mode (MMLE), press reset. Enter each byte of the program via the keyboard (or switches on V1). When complete program entered select RUN and press RESET, the code is now running (assuming the SSTP/CONT switch is in SSTP mode.

For a very simple program which simply reads the input port and copies this to the output port changing the input switches will result in the corresponding led on the output port being turned on or off depending upon whether the bit on the input port is a 1 or 0.

By selecting SSTP & SC mode and stepping through a program with the STP button you can see exactly what happens for every instruction cycle by cycle, observing the program counter, data bus and control signals on their corresponding leds.

By selecting Single Instruction rather than single cycle each press of the STP button will execute a complete instruction rather then a single cycle (useful for quickly advancing to a specific address).

The built-in I/O Ports can be used to read external signals and drive output devices like motors and buzzers with little or no additional hardware.

Still in use ?
After nearly 30 years the MPT808 is still in use, eg:
 * Kings College London - Forms part of the 2nd year Practical Physics 2008/2009.

It's also still available for purchase from Limrose Electronics.