Heathkit ET 3400 Microcomputer Learning System Motorola 6800 Microprocessor Evaluation Board from the Late 70 s Simple Assembly Program Demonstration The ET 3400 is an educational trainer from 1977 It is based on the Motorola MC6800 CPU It came with a whopping 256 bytes of RAM expandable to 512 bytes and a 1K on board ROM monitor program The Trainer was sold by the Heath Company Benton Harbor Michigan as a kit 190 or factory assembled 240 Heathkit ET 3400 Input Hex Keypad Output six 7 segment displays RAM 0000 01FF 512 bytes The following describes the loading and execution of a simple assembly program that loads ACCA with 01 and ACCB with 0F adds the two numbers in ACCA and saves the result 01 at 00FF Assembly program LDAA 01 LDAB 0F ABA STAA FF SWI Machine code in Hex 86 01 C6 0F 1B 97 FF 3F Loading the program into Trainer memory RESET AUTO 0000 86 01 C6 0F 1B 97 FF 3F Executing the program RESET DO 0000 Reading result EXAM 00FF Watch Video http youtu be Di3HnM Q3f0