Retail price was US$250: archive.org/details/byte-magazine-1979-01/page/n57/mode/2up

Definitely the Zilog Z-80. Built a literal ton of controllers with this chip. And I wrote it all in assembly in the Z-80 mode, and used mode 2 interrupts with the CTC, PIO and SIO/0. What a fantastic CPU. Just loved it. And it ran at 4 MHz with no gripes. In fact, I’m designing a GPS disciplined RTC with one RIGHT NOW!! I’m old, and so is the Z-80. But I’m not done yet and neither is that great CPU. The Z-80 was used in the Heathkit H-89. The video card for that H-89 also used a Z-80 and associated chips for driving the video. I had that H-89 for many years Used to use the Avocet Z-80 assembler/linker/debugger for CP/M with that H-89 and I wrote a LOT of Z-80 code on that machine. It was so reliable, it was amazing. I wish I still had it. Great video!! Thank you, Dave!!

Honestly as old as this is, it's still a great way for someone to learn how computers work at a fundamental, close to the hardware way.

My first microprocessor experience was in 1977 while was in the US Navy, using an RCA 6502 single board system (much like the MCS-85) called the KIM-1 (en.wikipedia.org/wiki/KIM-1). It got me to think in hexadecimal, and I had memorized nearly all the opcodes during the month I had access to it. In 1980 I got an Apple ][+ (because, 6502), and felt right at home, though I did get the Language Card with UCSD Pascal. When I left the Navy in 1981 I worked as a technician for General Atomics, which was transitioning their excellent-but-expensive analog radiation monitoring systems for commercial nuclear power plants to digital systems based on the 8085. I started university later that year (at UCSD, naturally) to study Computer Engineering, and was soon getting paid to write code for the 8085 using the Intel Big Blue Box and the PL/M language (en.wikipedia.org/wiki/PL/M). We had a final pair of analog systems that were difficult to replace with digital, and after graduation my task was to build the algorithms needed to let a slow 8-bit processor equal their performance. Some of the best code I ever designed and wrote, something I'm proud of to this day, and the best possible start to an engineering career I've loved ever since. Why did General Atomics choose the 8085? The simple reason was it had a surprising level of radiation hardness for a commercial microprocessor, hundreds of times better than the Z80, and dozens of times better than the 6502, for about 1% the cost of a "real rad-hard" processor (the 1802 was the only rad-hard game in town back then). It had other benefits, but all were minor or trivial compared to that. I took our systems to our "gamma range" (a linear accelerator) to zap them until they blinked, and it took an impressive level to make that happen. There were several tricks we developed and employed to further enhance its natural immunity, such as reducing the clock from 6 MHz to 5 MHz, and playing with the supplied voltage. And, yes, the systems were battery-backed with a Gates Gel-Cell lead-acid battery the size of your fist (both fists if you have small hands) that lasted for 5 whole minutes, 300 seconds!

I bought the SDK-85 in 1980, my first computer. Also ordered the Intel 8085 data book which had all of the instruction set and timing diagrams. I learned assembly language on this computer and had many hours of frustration and enjoyment. Thanks for presenting this.

Blasphemy. AMD Chips on an Intel Developer Board ;-)

I got one back in 1980 for about A$300. I still have the SDK in my museum and it still works. I expanded it with 4KB EPROM and 4KB RAM. The 110 default baud rate was used to directly interface with a TELETYPE. This was the ideal interface at the time as you had an input keyboard, a printer and memory storage (paper tape). I wrote an editor, assembler and EPROM programmer all on this unit. A typical 1KB program took about 2 hours to assemble (2 pass) and burn an EPROM. I have loads of happy memories (not)!

Dave does not seem to understand that this was aimed for ASR-33 Teletype. Hence the 110 baud speed. You stored your programs into paper tape. Dave should have tried the teletype monitor. There was special commands for outputting and reading the RAM to and from paper tape. I was dicking with this board in the Finnish Army in 1977. I built a testing device for a Russian Missile Controller, which was 3 ton electro-mechanical monster in a truck. This project was totally against USA-Comecon embargo. flic.kr/p/JycyMy

I called all those numbers, they've all been disconnected.

"Hello world" is about the extent of my programming ability, and yet I just adore microcomputer history. Excellent video Dave!

When you showed the support phone numbers, it really took me back. The 602 area code is for Arizona and at the time covered the entire state. When that technology was manufactured (circa 1980), I was a EE major at Arizona State University and lived just up the road from the Intel factory at Rural Road and Williams Field Road (now Chandler Blvd) in Chandler, AZ where it was made. Many of my EE professors had consulting gigs with Intel, and most of us ended up working on Intel-funded research at some point in school. It is interesting that they used local phone numbers for the support lines instead of toll-free numbers. I never worked on that particular programming kit, but did do a lot of work with Intel processors at the time. Ultimately, I ended up becoming an assembly language developer on the 808x, 80x86, 6502, Z80, 6800, and 68000 processors writing embedded firmware. Now I work for a bank with lots of high-end technology and it is not nearly as much fun. By the bye, the 121GW is an awesome bit of kit, so thank you for that. If anyone is looking for an excellent, affordable DMM, you'll not go wrong with the 121GW. The videos are just great, so keep up the good work.

Cool! I did a couple of projects on these back in college. I spent hundreds of hours wire-wrapping circuits and punching in programs. Thanks for the blast from the past, Dave!

The Zenith Z-100 used an 8085 processor as one of its two main processors (the other was the 8088). As one of the first "dual CPU" machines, it ran your CP/M program on the 8085 but CP/M *itself* ran on the 8088 :-)

We used these in college... 1980s.. but since, I bought two of them. Fantastic for what they are... a blast from the past.

When I was doing my Electrical Engineering Technologist Diploma in 1997, one of the courses was industrial control systems and we had that exact board to program 8085s for the lab activities. I remember having to program a servomotor controller using the 8085 and once you got used to the 4x4 keypad it was actually a lot of fun. The reason why they had the keypad layout as is was so that you had a block of 16 keys for the hex "data" values that were separate from the "command" keys. If you had ABCDEF across the top, you would end up with some of the digits almost completely surrounded by the command keys and a single finger slip could, to quote a Davism, "really ruin your day".

I have one of these which I rescued out of a rubbish skip from a place where I was working in the 1990's. It powered up but was drawing nearly 2 amps with a blank display and the CPU was getting hot. I put it away and forgot about it for over 15 years. After discovering it again the CPU was replaced and it's working perfectly. I even upgraded the memory and added the bus expansion chips. It's good to show people who only know iPads and PCs what early computing looked and felt like. Great video and enjoyed seeing something I own being eulogised on EEVblog.

I used one of these at college around 1980. We didn't have many sessions with them but I found even a bit of machine code programming gave me a good idea of what was actually happening inside a computer, compared to our high level language programming classes.

I joined Intel early 1980. There was a couple of the SDKs laying around the office. Can’t recall the price. This was generally pre-PC days so we sold the incredibly expensive Development System which supported several programming languages and with the optional in-circuit emulator sold for just over $10,000. Came with two 8” floppy drives!

External storage: wire up the TTY interface, connect to a Teletype Model 33 with PTR, enter paper tape, and Sadie's your aunt!

When I got involved with micro-computers (1981) I went straight to the Z80 camp and quickly learned to program it in assembly. I even wrote a bare bones assembler program in the built-in BASIC of the machine I got (NewBrain, for those who knew it and still remember). I enjoyed Z80 assembly quite a lot. And later on I did a lot of work requiring speed on 8088 machines as well. Another CPU of that era that I did some work was the NS COP402 - which was considered a 4 bit micro-controller.

I still have my 1975 SDK-80 (8080A CPU) board, It sold for US$250 in 1975 and was worth it's price in educational value. The kit cost was less than the price of buying just the IC's. The SDK-85 also sold for US$250 in 1977, at that time the 8085 CPU sold for US$110.

I had the tremendous chance to work with an Intel 8085 SDK.The one I used was from my boss, so I built my own using wire wrap and a small printed circuit for the display stuff, I still keep my homebrew 8085 SDK !!!. I learned tons of treaks and that practice and knowledge opened me the door to work with far more complex systems until these days. Thank you for this video !!!!

Absolutely amazing ! Almost so amazing is the touch and feel of this keys

When I was young I had a copy of the manual for this board, it's what got me interested in computers.

Good dose of nostalgia Dave, Best support ic was 8255 , i used it in many projects with CDP1802, Z80 and 6502.. Relativity cheap ? , this kit $1500 in today's money , my RCA CDP1802 cost $15 + shipping apx £100 now. it was an expensive hobby , but well worth it, still addicted age 77 ...

amazing stuff :-) Kinda brings back memories. I was taught microprocessor systems in school by a very similar development kit based on Z80 though. Dont remember if it was manufactured by Zilog or not but it was a little bit fancier than this board and had a Z80 in it. Our microprocessor lab was basically developing some applications on that board ...I just remembered one was controlling a traffic light in a cross section

Hex keypad... luxury. The Cosmac ELF only had switches. You get pretty good at hex to finger conversion after a while. :o)

Your history lesson on these old processors was great, so much info condensed that I had to pause multiple times and go back! Also so many of these old processors still power the world today that many young players would be amazed! The 8085 was released 7 years before I was born, today I work in the industrial field as a service tech repairing these, or to be honest their much younger offspring that is much less reliable and often without schematics as you addressed, so again thank you so much for all of this history, it is nigh impossible to learn it otherwise and get the full picture like this! :)

I remember in the mid 80's when I was a trainee engineer at the BBC training centre we had to do basic machine code programing on a Z80 development board. Later we used Z80 assembly language to write a verry basic disc controller on a Z80 based automation computer called the BBC Zeta which the BBC had develloped to automate remote unmanned sites like small transmitters and contribution studios. Watching you tap away on the hex keypad brought on a wave of nostalgia.

We were still using the SDK-85 in our microelectronics class in 1989. I was a BASIC programmer on 8-bit home computers in my early teens, and never understood assembly language until I sat down in front of one of these. The SDK-85 really opened my eyes to the workings of a computer.

This is just sooo cool, nice video 👍

I still have my 6808 training board. I also have the Micro - professor (Z80 system). Both of these have tape recorder input Jacks for program storage.

Support chips? Ben Eater wants Dave to hold his beer.

Here in Canada we also call it the Zed 80, hearing an American refer to it as the Zee 80 just feels... weird. Yeah I get that as an American design, Zee is correct, but I’ve always known it as Zed.

we used the 8085 in ceramic case for military products for both fixed and rotatory wing aircraft. and the RAC1802 for land and air products. As a youngster it was great to use the SEX instruction in the 1802 which was SEt X register. :) I can remember that the intel 8085 emulator was about £28K and off course as an ext apprentice who had just transferred in to the Research & Design (R&D) department i was not allowed to use it. But i did get my sticky mits on a MICE emulator which would constantly fall over, until I found it would run for hours with the case off and a desk fan blowing on it. Coming from the production via tests departments, I would spend my lunch time writing code to help the test engineers test and fault find the PCB's. The design engineer produced test equipment was a bank of switches for data, address, and read and write. so a board with 10 14bit dac's where they had to test every step would take days. So I fixed a duff computer board and put some test routines in that would do the complete test in about 10mins, it could also echo back test the rs232 board as well. You had to help the friends you had left behind.

At the University, by the 3rd semester we started to use the TTY interface to connect it to the TRS-80 model II (CP/M). This way we could keep our programs stored in 8" floppies. We also used the Z80 simbolic assembler with the help of a few macros to generate a few i8085 specific instructions. It was a big leap from assembling by hand and typing it in with the hexadecimal keyboard. Also the monitor program supported a number of commands to do the same operations of the kit keyboard and a few extra ones that allow for fill, dump, ... the RAM in large blocks, not sure if 16, 32 or more bytes per block.

The 110 Baud TTY would be for an ASR-33 teletype which, with paper tape, was the development tool for this kind of project. In 1976, there were no DEC VT-100's as you showed. That also would have left the designer with no way to save code in a machine readable form.

I remember that! We had one in college in the EE lab. So much fun entering all that machine code. None of that assembler rubbish!

My uni had these for their microprocessor programming class. It was a misery... write the program, hand assemble, type in the hex, and then debug. I was so happy I had a TRS-80!

I had an RCA Cosmac ELF single board computer, built it myself. I also had several different 6502 hand made single board computers. I built a single board system, based on the 6507 and using the 'sound chip' from a Commodore 'VIC 20" to implement a tone generator board for use in Honeywell Process Control stations, in use at Mobil Oil where I worked at the time. The engineer who had put me onto the project came in one day and was watching over my shoulder as I hand wrote the machine language code in a notebook. Why don't you use an assembler, he said. Buy me one and I will use it I replied. My brother Frank, who died in 2002, was in his final years of life working at a 'technical college' in Austin, Texas. I inherited from him a KIM-1 and an SDK-85 design system, just like the one you are reviewing in this video, they are treasured posessions. As was mentioned by someone else, this was intended to interface with a 20ma loop terminal. The last ad I saw online, back in the eighties, was for $149.00. Today, all these devices sell for much more than that on Ebay as colectables.

great episode !

I trained on the Lawrence Livermore trainer which was very similar to this board. It was 8080 based. My first machine language program was a perfect emulation of the traffic light in front of the school. Prior to that, I learned basic (sort of) on the Commodore PET with the chicklets keyboard. My Morse code transmitting program was bootlegged by the rest of the class. I was honored. My processors in order: 8080, 6502, Z80, 6809, 68K, 8088 and derivative, and MCS-51 and relatives. Then the line was crossed where I could purchase hardware and software for less cost than my development time. Ah, those were the days.

These kits are a lot of fun. I used a Heathkit et-3400 in the late 70s. It was a neat system for learning how to connect a processor to external devices.

I still have my Motorola D2 kit. In the late 1970's used that kit to design a 6800 CPU card for S100 bus and got FLEX OS running on 8" SSSD.

I used to work at Warburton Franki in Adelaide. They were the Intel distributor in Australia then. Many of my customers were engineers at DRCS (Defense Research Center Salisbury). ...aaaaaaah what memories :):):)

The 6502 is my jam. It powered so much of the kit I used as a child!

Your board is missing a part. The kit included a couple of strips of double sided tape and a piece of transparent red acrylic plastic. The last step in construction was to tape that plastic to the LED displays. It vastly improved the readability of the display. I worked part-time as a tech in a college in the early 1980s and spent most of a summer assembling these kits. It got to the point where I could assemble one from memory in about half an hour.

That was my first toy. The University I attended had lots of those. The next one, i8086, we design it in house writing our own monitor code, largely based in the monitor of this kit. BTW, I think I still have the commented listing of the MCS-85 kit monitor. And also a pocket size folding sheet with all the ASM opcodes and their haxadecimal codes, that we used to and assemble the programs so they can be inputed with the haexadecimal keyboard/display of the kit.

Nice! I love the 8085

I'm fairly sure that the first Prodigy computers had 8085s. I think later ones had a Z80, though. There is no mention of them anywhere on the net, but I was using a language / OS called Protege on them in 1984-86.

Love the vintage Intel packaging

Back in the late 1970s I wrote the code for an 8085 based Morse Code ident module for use in Amateur Radio repeaters. I designed the whole code on paper using my own pseudo assembler language, simulated the code and all the variables on a large sheet of butcher paper by hand, converted the code to hexadecimal opcodes and addresses by hand, and then single stepped the hex code into an EPROM burner. A friend of mine built the hardware and sold the boards to various people around Australia. I am now not 100% sure it was an 8085 because I remember there only being 128 bytes of RAM and 1K bytes of ROM available. The 8085 does not seem to have either although there may have been a other chip with memory in our design. I recall my friend wanting to use the 8085(?) to reduce parts count by not using external memory chips. Those were the days of compact code. :)

reminds me of the old Z80 trainer boards... programming assembly in hex was always great fun!.. aslong as ya had the opcode list handy.. and used ya brain.. ya could do anything!

As I have grown up in the GDR my fav cpu is the U880D, which was the one I made my first steps with computing. Still have a working one at home, and use it from time to time. Love my KC85. The floppy was very expensive, and I was able to get one as well.

I still have the SDK-85 , also have the Z80 System Desing Kit from SD Systems and I love it!

I remember the SDK-85 so well. It got me into microprocessors in a way I could understand to build projects. At the time it was amazing to have such incredible power - it was like leaping 30 years into the future compared to analog circuits. I remember the lecturer on the first day of the 8085 course saying - "nothing you've ever seen before can do what this can do." I passed my courses on it by practising on my own SDK-85 kit that I still have. The only thing that annoyed me was the volatile memory - to get the program onto an EPROM was a major task. I think - even today - that all computer programmers should have to start out on an SDK-85 kit - or something similar - so that they can really see and understand what is going on at the most fundamental level - which is quite simple once you grasp it. I'll also add that Intel made it easy to understand their 8085 compared to the Motorola 6800 - which was harder to get going owing to lousy notes and a book etc. Intel's documentation was 10 out of 10 - perfect.

I learned assembly on that thing back in 1982. Paid for all my classes that semester by writing multiple versions of my programs and selling them. Fun stuff!

Wow! We used similar (generic) 8085 development kits in my high school Computer Science class to learn assembly language, just a few years ago!

In the 70's at university I learn't on Z80, about 10years later I purchased one of the Z80 kits from the university as surplus equipment. I have it stored in my garage, included power supply built underneath it by university staffer and has S100 bus down one side. I think you could get a BW monitor plug in board to help see what was going on.

I still have an MCS-85 board stashed away in an old briefcase. I was using it at Medtronic in the early 1980's to evaluate a semi-custom mixed signal IC that Exar produced. The Exar chip was a metal mask programmed analog array, which was much faster to develop than a full custom mixed-signal chip and a better solution for low volumes. The MCS-85 board has date codes of 1980 on the chips and still has the EPROM to run the evaluation program as well as an Exar protoype with a date code of 8243 (late 1982). All of the chips in the breadboard area are wire wrapped. When the project finished I took the MCS-85 board home, thinking that it would be fun to play with. It has been in a closet ever since.

More of these please :)

I have used Z80, 6502, 6809, TMS1000, 8080, RCA1802, 8086, Mc14500, Intel 3000 series, Cyrix fasmath, Hitachi HD68xx and finally 68000 on breadboard experiments

Nostalgia alert!!! You have got to watch the documentary series here on KZfaq called "Calculator Wars" and "Birth of the transistor". It was silicone IC wars between USA and Japan. A lot of fun and I remember everything had a calculator on it (rulers, binders, watches...)

Thanks for that summary of processor history. I'm always stunned how fast we got. There where sub MHz IC processors? :D In the 90s, when I was a boy, my dad was probably running a Pentium at blistering 100Mhz and yet another 20 years or so later I'm running some 12 core 5GHz monster.... just to watch youtube :)

Thanks for the video, it was very interesting!!!!!!!!!

I've still got my 8085 SDK just like the one Dave used. It taught me a hell of a lot. I really felt I knew how computers work after writing many assembly language programs. The students at Uni today should use those kits to get a better understanding. Deep down it's so simple once you work it out.

6502 fanboy here. Even today, seeing 6502 assembler gives me that ASMR. It’s just all tingly! Which is NOT the same thing as sticking a 1 Meg resistor into the mains, btw! 😆

Great stuff

We used the SDK-8085 (MCS-85) trainer when I went to Tech school in the late 70s. Had to wright programs and interface it with circuits to control motors, test ICs, program it for a clock. I still have all of my labs and programs. I don't own an SDK-85 but do have a Kim-1 which uses the 6502. I bought the Kim used at a ham fest over 25 years ago for $20.00.

In Electrical Engineering university, I hear we will learn about the 8085 on second semester's digital tech, as it's one of the most powerful processors we can still fully undestand in that time. I'm sure though we won't be using this kit...

When you were discussing the history of these microcontrollers one significant one you forget was the RCA 1802. This was a popular hobbyist chip and it was significant in that it was the first CMOS low power micros. We had one of the COSMAC ELF computers in our computer science department in high school in the late 70's. I do have a soft spot for the 8085 however as I built up a controller board from scratch using the 8085A Cookbook by Jonathan Titus as a reference in the early 80's. I have also found 8085 boards used as controllers in scientific equipment from the 80's.

Fun fact: the Intel 8008 is actually totally unrelated to the 4004 (marketing was a thing even back then). The 8008 was a microprocessor implementation of the solid state processor of the Datapoint 2200 terminal (designed in the late 1960s and announced in 1970), which not only provided some processing power of its own, but was probably also the very first real-world PC. Datapoint commissioned the microprocessor implementation to a few fabs, including Intel, Texas Instruments and Fairchild. Intel was the first to actually deliver (I believe, TI was a bit faster, but didn't meet all of Datapoint's specifications), but only late so. (Part of this was for prioritizing design on the 4004, which had been started only after the initial work on the 8008.) However, the original design of the DP 2200, the microprocessor was to replace, was built around a single-bit, serial shift register, and had been replaced in the meantime by a parallel multibit TTL design already. Hence, the microprocessor was slower than what Datapoint had already on the market and not of further interest. (In fact, DP [then CTC] TTL processors remained faster than the respective generation of microprocessors up to the 386-era, when they were finally phased out.) In order to reduce losses on the commission of the now useless chip, rights remained at Intel, who tried to figure out ways to market it over a few years. (Which eventually gave us things like this development kit…) Fun fact #2: CP/M was written for the Intel 8080/8085 (with the Z80 being supported as a superset, as well). Insofar, not a that unimportant processor…

I am so glad I saw this. I have been agonizing over the best design for a hex keypad for my Z80 computer and now I am stealing this one! It is perfect! ^.^

I was a 6800 person. I got a cheap 6800 D1 kit in 1979 for £50 and it never worked because I sprayed it with lacquer and it went into the sockets and insulated the pins. Took the chips and put them on proto board, added an old CBM calculator as a keyboard and display. Coded a new monitor program by hand and eventual memorising the instruction set. Designed a hires graphics TV display for a friends Z80 computer. Later on built a 6809 computer using scrap 8 inch hard disk drives. Had a TV output and again hand coded firmware. First week of work, 1984 bought a 6502 based BBC Micro..

That brings back a lot of memories. Good times.

I got one to keep when I did a couple of weeks micro course at Aston Uni (Birmingham UK) back in 77/78. I only recently parted with mine

Oh the memories! I borrowed the 8085 sd kit. Later bough an 8080 Sol system. Used S100 buss ram board, 8k byte, kit for the ram board was about $230.

The 8008 and 4004 were parallel projects with no technical connection between them. The 8008 was an integrated version of an existing architecture, which was implemented by Texas Instruments as well: www.righto.com/2015/05/the-texas-instruments-tmx-1795-first.html My first computer was the Motorola 6800 equivalent that you showed at the end (MEK6800D2). In 1980 their local office was throwing it away as obsolete and I was glad to take it off their hands for free. It had "punch" and "load" keys for storing programs externally on paper tapes if you were using TTYs. The best processor of that era was the TMS9900. As long as you didn't cripple it like in the TI99/4.

Old good memories of 8085 learned in college......☺

I have a little memory from around 1980. Our first computerized controller was launched then. It was designed and built by a small company in the same city and was built around a Motorola 6800. It ran at 1 MHz clock speed and I asked the head designer why he had selected the slow 1 MHz processor, when Intel had much faster ones. Mind you, I had no experience whatsoever about microprocessors. So, he picked up two data sheets and showed how the Motorola chip ran most of its operations at 1 or 2 clock cycles, while the same operations on the Intel chips took maybe 6 or even more cycles. So, there was essentially no effective speed differences. Lession number one. A few years later I inherited the task of interfacing with the same company when the last incarnation of our controller was designed by the same company and design engineer. It was based on Motorola 68000. I again wanted to know if it was speedy enough, as then the input and output channel count and other performance specifications had increased radically. I kept asking for an estimate. Finally the main designer agreed to sit down with me and "sow it was fast enough". Some 15 minutes into the clock cycle counting he got uneasy and then said "You are right -- it cannot do". So the design got 3 coprocessors (6803) to handle I/O while the 68000 did all the math and oversight. I still don't know much anything about designing a system with a microprocessor,, but keep this experience as a treasured memory.

Wow, that's way more sophisticated than the Motorola D2 kit I started with. That one had a hex keypad, but little else. The debug monitor did almost nothing. It's a great way to learn though. Engineers today are missing out on that fundamental experience of understanding address decoding, and grasping how op-codes work right down on the hardware.

SDK-85 and M6800 Kits were used by my University to teach programming with Assembly Language and Machine Code. NCSU Class of 86.

I graduated college in 1969. I remember how exciting it was when Intel introduced the 4040. There are, even today, many traffic light controllers using the 4040. They were reliable as all get out. After the 8088 was released i built myself a 16k print spooler using it. Back then, if you wanted to print something big it would tie up your computer for what seemed like hours. With that spooler installed between the computer and the printer I could send the "print" command, and go back about my business on the computer while listening contentedly to that awful racket made by the 9 pin printer!

I was working at a university in South Africa at the time and had to build and test 30 or 40 of them to use in a Microprocessor Course which I even attended myself! Great times!!!

My first microprocessor in the 1970s was the obscure RCA CDP1802. No fancy development system for me. Being a masochist, I wire wrapped together a system with 256 Bytes of RAM no ROM, and Hex LED readouts. But it did have composite video out you could use it to create a terminal with like 20 or 40 character lines. Input was initially toggle switches. At least there were only 8 switches. The processor had a Load mode which would auto increment the address. My first upgrade was a Hex keypad. My first post-university job was programming the 8085. Next the 6809 with a little 6502. Then onto boring PCs.

Nice. Made me think about a similar 8080 demo board i 'worked' with. Even wrote a basic crossassember and a simulator (in HP shared basic) to make the programming a little bit simpler. And BTW i had not a nice electronic keyboard/display. Started with a teletype ASR 33 with paper tape....

that was my first "Computer". Great stuff.

The Commodore PET was actually based upon the 6502 KIM development board. The differences were minor, and the PET had a display chip, but about everything else was the same architecture. The reason for this was that the KIM and the PET were both designed by the 6502 engineer itself.

Those keys are a thing of beauty! I would take a mechanical keyboard with those keys right now!

I learn microprocessors with a heatkit 6502 kit, I love that beauty

i have a Micro-Professor MPF-I which is a Z80 version of this, but has much better and bigger displays, and a much expanded keyboard(keys sucked tho, very small) with far more functions, and it had much more ram and rom(2kb), expandable even. Funny thing is that the microprofessor is still sold(or at least it was a little while ago). My father used it a lot when he was young and he made a EPROM programmer board and associated program(quite a complicated board full of components!), the MPF-1 had the benefit of being able to save and read from audio cassettes, none of this "losing your program" rubbish. Very advanced bit of kit

Of the processors you listed my favorite would have to be the MOS 6502. It was used in the PET, the VIC20 (my first computer), and in various models of Commodore floppy disk drive like the 1541. They’re still being made to this day, I think by Western Design Center. But of the ones not listed, my favorite is the MOS 6510 because it’s in the Commodore 64, my favorite computer line.

The stuff I built was with a Motorola 6800, probably better than an 8080 somewhat. The first project was an Amateur Radio Repeater, which went live in 1976. Later I wrote a complete operating system that ended up being the basis for an answering system computer (7 terminals at 9600 baud). The machine had 60k bytes of nice static RAM in about 1980 or so. I still have a chassis that I worked on back in the day. Lots of memories from that era! The kit I started out with was from Motorola and cost $300 (US) at the time (1975).

We had those in our school (vocational college) back in 1990.

My fave processor was the neural-net processor, a learning computer. It became self aware on August 29th, 1997. The rest is history...

You've got a later kit. The 8085AH shown in your kit is at the earliest, 1980. I started with the 8085 (no suffix) in the later part of 1976. It had a couple of annoying bugs, among which was a buggy reset. The 8085A came a bit later (1977?).

I still have one of these kits. Mine had the system ROM replaced with the 8755 EPROM version. The problem is that the EPROM was blank! I had to build a programmer for it, then get an accurate copy of the source code to recreate the binary. I finally got it working last fall.

Excellent

Used a similar smaller board in the Late 80s at college. I think it was 6809. It had an output speaker. First program I did on it drove the speaker with an incrementing pulse delay. Drove the lecturer nuts! haha.

Since you asked :-) Heathkit had a very similar kit for the 6800. Entered the program the same way, executed the program the same way, etc. It was the et-3400. I got one for free, but it didn't work, so I used the keypad for another project. I cover the 3400, as well as a et-3400 simulator, and other kits in my vid: "Nostalgia Time: Old Electronics Kits"