My Home Made Z80 Computers

[im_a_human]

Hello! i have some home made projects to show everyone. Z80 computers! I have been a fan of Z80 based systems for along time now, 20 years in fact. These particular ones in my photos which i will show you in a bit are based on a very popular system that i believe is still available to buy at:-

http://www.flite.co.uk/microprofessor-mpf-1b-z80-training-system.htm

I first used these at Brooklands College in Weybridge, Surrey, in the UK 20 years ago!!! I liked them so much i decided to build my own. And here are my versions:-

http://www.flickr.com/photos/32042005@N05/

This is not all of them as i had made six systems in total. I sold three sometime ago which i wish i hadn't done now. Anyway what ive done is to build and customise the existing design onto veroboard and
add lots of extra features that would be really usefull that didnt come with the original. The original Microprofessor had a CPU clock speed of 1.79 Mhz and at most 10Kb of onboard ram. My Most recent build of this computer which ive made this year, i gave it a clock speed of 12Mhz! and 256KB of battery backed ram!
Lots of the features of my systems are to do with making music and you can see they all have MIDI serial ports. The two larger ones also have 8 bit analogue to digital converters and 8 bit digital to analogue converters for sampling and playing back audio and also for audio signal processing.
I have various bits of outboard gear to go with them as you can see in the photos, LCD displays and a  retro LED matrix game board which i want to use to recreate John Conway's Game Of Life on.
Also in my most recent build im making an analogue synthesizer controlled by the computer which will be incorporated to the system and allow me to play it with a MIDI keyboard.
Well ive gotta fly for now but i will be back with more info on my projects so feel free to leave any comments or questios please.

[bound]

Hi , have a look at this  :http://www.retroleum.co.uk/category/progress-report/
best z80 sbc ever !!

[im_a_human]

Hello again!
Ive been working on my Z80 computer projects and i have made a simple implementation of Conway's game of life you can see here:

[Ferroto]

Impressive. I dare you to try and get that past airport security

[RayJones]

LOL, reminds me of the time I was carrying an Agilent Noise Source past security.

Never seen so much interest in a piece of test equipment by the hired goons.
When I told them it cost several thousand dollars, they gave it back real quick in case they dropped it 

But yeah, that game of life would never make it far I reckon.

[saturation]

Nice job, clean and professional!

Hello again!
Ive been working on my Z80 computer projects and i have made a simple implementation of Conway's game of life you can see here:

[CryptLordGR]

Excellent work i hope i make such a machine in the future too.

[gushh]

Impressive. I dare you to try and get that past airport security

Exactly my thought! -- You can't even have a few ICs in a bag without having them shove you inside a tiny dirty room and interrogate you!
What has this world come to...

As per the original topic, I'd like to see that 12MHz Z80 do something actually useful. Impressive work, but can we move away from games and run actual applications? -- Take a look at the Magic-1 project for instance (not exactly the same, but the guy actually runs a web-server from it!)

Before you jump the gun, I will add that I understand the complexity of Conway's game of life but that's all we see from home-made Z80s, etc. Just games... Why is that?

Pardon my posture, I just had to ask.

[im_a_human]

Dont worry  ive got much more things i want to do with this. That 12Mhz Z80 computer isnt even finished yet! Theres another board to go on it which is going to be the analogue synthesizer for making music. Its still in the development phase. Two VCO's, an LFO, two envelope generators, a VCF, and a low pass filter and audio sampling. My 4 x 40 character display will come in very handy for showing the synths settings.

[BlackCow]

Those are very nicely put together!

I've been working on an Intel 8085 based microcomputer.

It has 32k EEPROM, 28k Non-volatile SRAM, a UART and an 8255 I/O controller (not yet wired up). It's still a work in progress, its been a lot of fun. I have it interfaced with a very retro terminal (much older than me) from 1979. In the picture below its hooked up to a small serial display.



The ultimate goal is to have the 8255 IO controller interface with a floppy drive so that I can load programs into RAM off of a floppy.

Unfortunately I have to hand assemble all of the code in a hex editor, I haven't been able to find any 8085 assemblers online.

What do you use to assemble your Z80 code, and is there something like it for my chip? (or do you just hand assemble as well?)

[im_a_human]

@blackcow hi, excellent work you have done there. ?
I hand assemble all my code and write it out on paper then type it into the computers RAM?
using a program called a monitor. It can be hell if i find a mistake when ive written a large program and have to re-write partitialy some of the code. There are assemblers for nearly all microprocessors. It can be difficult to find certain assemblers like these
since the 8085 hasnt been around  for quite a long time. I can only say dont give up searching.

[joelby]

Unfortunately I have to hand assemble all of the code in a hex editor, I haven't been able to find any 8085 assemblers online.

How about http://gnusim8085.org/ ?

[BlackCow]

How about http://gnusim8085.org/ ?

GNUSim85 is a great program, unfortunately it is only a simulator but does not assemble your code out to a hex file 

Its helpful for testing code though. Maybe I can write my own assembler haha.

[joelby]

That's a shame. It does have an assembler, so you should theoretically be able to add a function to save the memory to hex once it has run, or convert it to a standalone utility.

[Polossatik]

Unfortunately I have to hand assemble all of the code in a hex editor, I haven't been able to find any 8085 assemblers online.

a quick google for 8085 assembler yield a few like http://www.planet-source-code.com/vb/scripts/ShowCode.asp?txtCodeId=63780&lngWId=1  and payed (25 € for personal use) http://www.oshonsoft.com/8085.html

not checked anyone of them..

Can't recall what I used early 90's with the 8085 style stuff i made ..

[im_a_human]

Hello again everyone 

I had to go and build a larger 16x16 LED matrix. Heres a photo of it during construction...

[im_a_human]

And here is a photo of the finished board showing Conway's game of life...

aaannnd I will have a youtube shortly...

[im_a_human]

Ok here is a short video demonstrating the game of life. enjoy... oh and i will try to post a circuit diagram soon as this is a very straightforward design and could be adapted to any micro controller or computer project.

[im_a_human]

Hi everybody, its been quite a while since i last posted any topics but i have finally got round to drawing the circuit diagram for the 16x16 LED matrix. I used the free CAD software called Design Spark for this then i exported it as a .PDF file. You could use this with any microcontroller or computer with two 8 bit parrallel ports.

[im_a_human]

I probably briefly mentioned in another post i made that i cant find now that i will be building a MIDI sound synthesizer into the most recent Z80 computer ive been building. (the one with the 12Mhz clock). After about nearly 2 years of trying out different ideas with analogue circuits built on breadboards i wasnt satisfied with the sound. The oscillators and filters sounded thin and weedy and theres not enough board space to implement a true classic synth design with all the dozens of discrete transistors circuits. So i decided to go for the digital option. Ive been doing a bit of PIC projects and programming over the last 9 months or so and using MPLAB and the free C compilers and the PICKIT 2 and 3. I was looking at the PIC's available and saw the DSPIC33F series. Ive seen on youtube theres a guy who implemented a DSPIC synth design and it sounds fabulous so that reasured me this was a very good path to take.

So i bought some DSPIC33FJ128GP802 parts because these come in DIP packages which is good because its going on verobard and also because it has stereo 16 bit DAC's on the chip. It took me several weeks to get my head around the datasheets and the refrence manuals and get the oscillator running for this part but now i do have a photo of my initial setup for developing the project. It only blinks an LED at this moment in time but it does run at 40Mhz. here it is...

http://www.flickr.com/photos/32042005@N05/6298918077/#

First i want to create a VCO for sound waveform generation and i realise that digital signal processing can be frightingly complex subject but im not going anywhere fast and im not a quitter. If you have any questions please ask. Thanks for reading and i will be back soon.

[Rufus]

If anyone from this thread is still hand assembling code, I wrote simple (one source file, hex and list file output) 8085 and Z80 assemblers years ago.

Will be DOS executables if I can find them, might be able to recompile for Win32.

[im_a_human]

Hi Rufus, Hey that would be great as i dont own a PC based Z80 assembler so i would be very interested in using your Z80 assembler thanks, please could you send it to me. Thanks.

[Rufus]

Hi Rufus, Hey that would be great as i dont own a PC based Z80 assembler so i would be very interested in using your Z80 assembler thanks, please could you send it to me. Thanks.

I just compiled them for Win32 with no real testing so it might have caused some problems. Both assemblers are attached.

do

asmz80 -l try

and look at try.lst for basic documentation I wrote for someone else I gave it to about 20 years ago, the 8085 assembler is very similar.

edit:- should have known I would screw up something, changed the attachment to just the z80 version which now hopefully doesn't need any DLLs. If someone wants 8085 version ask.

[FreeThinker]

How about http://gnusim8085.org/ ?

GNUSim85 is a great program, unfortunately it is only a simulator but does not assemble your code out to a hex file 

Its helpful for testing code though. Maybe I can write my own assembler haha.

Not used this myself but if it is half as good as his Pic simulator then I can strongly recommend it. It's http://www.oshonsoft.com/ and he does an 8085 (and Z80) simulator/ assembler and disassembler for 25 euros may be worth a look. You can also download a 30 trial for free. Hope it helps

[Lawsen]

My only experience with the Zilog 80 was the Timex Sir. Clive Sinclair computer with the membrane keyboard and it costs a mere $99.00 USD, which was a lot for a teenager at the time and the minimum wage was a mere few dollars per hour.  It out lasted my brother's Macintosh SE/30.  It depends upon a television set as a display.