View Full Version : My Heathkit ET-3400 Microprossesor Trainer

June 22nd, 2008, 03:02 AM

Here is another detailed (meaning long) post on my new Heathkit ET-3400 microprossesor trainer. I had bought the three workbooks separately and I started at the beginning. It told how to enter a program and then listed a program that tests your ability to convert binary numbers to decimal. I entered the program. The trainer only has a hexadecimal keypad - the keys have secondary meanings at certain times determined by the monitor program. My trainer has an "E" key that sometimes doesn't work.

Next up was checking that the program was correct, and then running it to take the test. The book said that I should get ten numbers correctly converted before going on. I pressed the key that means "Go" and entered a four digit starting address in hexadecimal (0002). The trainer flashed a six digit binary number and I figured out what it was and pressed the "D" key to indicate I was ready to answer. The binary number disappeared and two digits displayed underlines, which were prompts for my input. I put in the number and after what seemed longer than the "one second" the manual said the display showed "yes go". I pressed the "Go" key to continue.

I got nine numbers correctly converted until I incorrectly entered "9" instead of "09". The display said "no" and then the binary number displayed again. I entered it correctly and decided that misentries didn't count as a strike.

I was just wondering if there are any similarities between the 6800 microprocessor in the trainer and the 68000 C.P.U. that Macintoshes use and the 68020 that runs a satellite that my astronomer friend programs? I actually bought a whole 'nother ET-3400 to get the flip chart and cassette tapes that are part of the course material. I am hoping that the flip chart will tell me what the op codes are, so that I will be able to write programs for the experiments later in the book.

All in all, I like it. It's the first computer that I've seen that doesn't have a polorized plug, or a grounding connection on the plug, for that matter.

I recently had a Google alert send me to a blog who's owner had successfully interfaced a thumb drive to his ET-3400. Wow.


August 23rd, 2008, 07:40 PM
Yahoo group dedicated to the ET-3400!:


October 10th, 2008, 01:33 PM
Heathkit isn't bad, I'm using one of there books now.