Midwest Gaming Classic Single Board Computer Part 1

[@rogerfurer2273]

My very first computer was a Timex Sinclair. Z80 based. I broke it out to a breadboard and had all kinds of fun learning. Nice to see the old gal getting some attention. Cool project.

[@marc6340]

The fact that they make a surface mount Z80 literally blows my mind!

[@nessotrin]

TI calculators use 8080 CPUs (or Z80, I forgot) to this day.

[@absalomdraconis]

@@nessotrin : I believe it depends on the model.

[@Decco6306]

You should check out the other products zilog makes. they make some pretty cool z80 based microcontrollers. even 16 bit versions. Dig around on Mouser and Digikey

[@parrottm76262]

Code? Boring? Never! Great project. Thanks for allowing us to look over your shoulder.

[@dylansternbeck9230]

By watching Ben Heck, Ben Eater, and Primitive technology videos I'll be able to create a computer from rocks in the wild.

[@McTroyd]

Gonna need to watch a few more channels to get the raw materials first... but yes, you're probably right.

[@chromosundrift]

​@@McTroyd There should be a global skill tree of alphanerd mastery. So what sits between primitive technology and Ben Heck? And then what's after Ben Eater? :)

[@Billystone90]

When your done you should sell them or something like it as a kit I would love one and want to support the channel

[@farhanyousaf5616]

This! Perfect way to support and get something to play with!

[@LittleRainGames]

@@farhanyousaf5616 yeah i dont underatand why electronic youtubers have patreon. They could easily sell their creations, and then the people would would give them money on patreon also get something cool, other than the videos of course.

[@OldManTheseDays]

That would be cool, but it would take a ton of money and time to do those kits and he wouldn’t see as big of returns as you might think.

[@tainicon4639]

He Just posted a video assembling one!!

[@MaxintRD]

Nice project! I vote for loading memory from SD card to enable easy change of programs. Having a keyboard input, speaker and video output would also be nice.

[@vinnycordeiro]

But you CAN draw a line over characters on Eagle! Just enclose the string with a !, like !CS! (you actually can skip the ending !, but it's good practice to use both if you are writing a longer string and only part of it has the over line.)

[@crispoman]

Handy hint: Eagle will stop the overbar at the end of an entry in a bus list, so you could have "!WR,A[0..15],!IORQ" and it would only put the bar over the WR and IORQ sections.

[@vinnycordeiro]

That's not the behavior I get. But again, I'm using Eagle 7.6.0, which is the one I have a license for, could be a feature of newer versions.

[@BenHeckHacks]

Registration now open! www.midwestgamingclassic.com/workshops/ 15 spots left as of 2-20-20

[@1stage]

Wow, the code section was actually WAY more interesting than I expected!

[@RoamingAdhocrat]

30:00 that is a beautiful block diagram.

[@SlyEcho]

22:30 Putty has an option under Terminal > Keyboard to select the Backspace key.

[@RupeeRhod]

Cool concept, I think what people would love most is some sort of low power display mode and/or a very limited amount of on board power. So let's say they could run the badge itself for like 30m to 1h without having to use a powerbank. Not sure if that's possible but any amount of time they could walk around with the badge at MGC without needing any externals I could see increasing the likelihood of it happening or increasing the scale of it happening many fold. It's such a good conversation piece in like "I made this" and "look what this can do" even if it's for a short period. So if any reasonable amount of double or triple A batteries or lower profile of the disc batteries could facilitate that, I think that would be a great addition.

[@yorgle]

If you want CP/M, you might want to have a microsd card slot also on that spi bus, rather than eeprom. Even if you don't use a FAT FS on the 32u4, you could access direct sectors to provide them to CP/M. ... or go with FatFS on there, (or something custom) and also provide a selection of ROM images to boot into... perhaps? RC2014 bus compatibility would be neat too... so you could plug in the TMS9918A video card in, or joystick controller card... etc. :D

[@richa9719]

Dude, you are wicked smart.

[@calabrese1531]

Rich A InDude! Uh oh! I mean, indeed!

[@minibigs5259]

I always think "Wasted as a graphic artist"

[@jarisipilainen3875]

3:38 atmega on z80 computer.everyone allready have usb serial so only pin header needed if not arduino board will do

[@josiecooper8012]

Really cool board and idea. In eagle you can use "!" to start an active low naming and another "!" to end it. So if you want "/enable" you can use "!enable", or for "read//write" you can use "read/!write!" etc. Hope this helps ^^

[@MrCukydoh]

it's so good to have you back man

[@paule6101]

Looks great, I'd definitely buy a kit if you ever sold them

[@obiwanjacobi]

Display and SD-card are very good options. A little joystick or rotary encoder (with push?) would allow you to really interact with it stand-alone. Nice design! ;-)

[@BrainSlugs83]

You could always intercept the backspace key and print Ctrl+H as well. I would add a battery to just run the badge. Instead of using a crystal oscillator, I should set a fuse on the mcu that dumps the internal clock to an IO pin (ATMEGAs usually have that). If you use one of the more modern Z80s (like a Z380) that should just the power requirements. You could also use the ATMEGA to replace the memory glue logic (just use one of the pins as a not gate).

[@BenHeckHacks]

All good ideas. Yes I plan to use the PLL 96MHz clock for Timer4 to clock the Z80. Then the user can stop the clock and single step if they wish.

[@cerberes]

Great Idea Ben

[@absalomdraconis]

You should provide battery backup as an unpopulated header on the board. Also, a plain-jane parallel port on headers: 8 bit bidirectional data, 8 bit out-only address, clock out, ground, interrupt in.

[@electronash]

5:05 - You can usually add the "bar" above characters in Eagle, by changing the forward-slash for an exclamation point. But to do that on the symbol itself, you'd have to use the Library editor. The bar thing does tend to look a bit untidy when signals are close together, though. Instead, I tend to just add a _N to the end of signal names, like OE_N, CS_N etc. Do you buy your chips from a specific site in China, btw?

[@proxy1035]

personally i would always recommend a legit international chip seller like Digikey or Mouser for buying these things. both sell Z80's as well, and Mouser also sells new 65c02's

[@crispoman]

A bonus side effect of adding suffixes to signal names is that if you have an "_N" and a "_P" you automatically get a balanced pair - useful for USB routing (line-length balancing using meanders, etc.)

[@electronash]

@@crispoman I usually avoid that, for some reason, and still route diff pairs manually. I did try doing length-matching for the RDRAM on a Mini N64 board I designed, but I admit that putting the traces and vias for the SDRAM on between the RDRAM traces was a very bad idea. lol i.imgur.com/6pUL9jw.png The board does "boot", but only at 4/5 the normal speed. I've improved a lot since then, and use Altium for the more complex stuff. I do still like Eagle for smaller projects, though. It loads up fast, it's easy to copy the files around to clone projects, easy to use its library editor etc. And the newer versions have finally added things like labels to the traces and pads on the PCB viewer, and don't overlap the traces any more whilst routing.

[@doc_sav]

A little PC speaker type thing would be fun to play with and add a little more "flair". "Serial loop... Sounds delicious."

[@HisVirusness]

I can't wait to see this in-form.

[@joneilkimball]

I got an old controller from work that used to control the in floor heat. It has a z80 based cpu, a keypad layed out for calendar and time inputs, 12 relay outputs, 8 analog inputs, rtc, and 16 by 2 character lcd. It also has an expansion connector for more devices. I'm trying to think of a home automation project I can use it for. I just want to do more than a thermostat or timed lights.

[@absalomdraconis]

Lawn sprinklers.

[@joneilkimball]

@@absalomdraconis It would be good for that. I don't water my lawn though. My garden is too far from the house to automate watering also.

[@AllenKll]

Looks like an awesome project. A couple of buttons would be nice. One on each side of the screen? By default, maybe they don't do anything, but allow access. That would allow people to make working games on their badges, and add minimal cost. One might think.. what can you do with two buttons... but think of all the cell phone games that only use jump, or jump and duck, or jump and shoot, or a gas peddle and brake, turn left/right... there's tons of things. But some sort of basic user input while in 'badge' mode would make it much more exciting to the random passer-by at the convention. Imagine seeing someone with an interactive flappy bird clone on their lanyard, or a temple run clone, Or B.C's quest for tires.

[@AllenKll]

Or even some sort of +/- counter... of people who think their badge is cool / not

[@snoballuk]

I'm always cheered when I'm reminded that Ben uses the same 20 year old keyboard as me.

[@TheChenkar]

This was a great video! I've been thinking cpu logic a lot lately. I've designed a 74ls based subleq cpu which I've actually received almost all of the parts for my prototype. I'm currently learning about stacks and kernels, as well as figuring out how the boot program might load to ram and disable the rom to free up memory space

[@masar-at]

Watch this kzbin.info/www/bejne/rnPNgomui92CrsU

[@Otakunopodcast]

Honestly I think the SBC is fine as is. KISS and all that, not to mention it keeps the cost/parts count low. I mean, you have the expansion connector on there already, so it can be left as an exercise to the attendee whether or not they want to add certain features. One possibility is to MAAAAAAAYBE make the board a little bit larger so that you can fit in a mini proto area (basically a grid of plated through holes, where people can solder their own stuff.) Also, as others have said, it would be awesome if you could sell this as a kit somewhere, or at the very least post the Gerbers as well as a BOM somewhere. I won't be able to attend MGC (it's just not in the budget this year :-( ) but would love to experiment with this.

[@coolduder1001]

good timing, was looking at z80 kits. I wish someone would make a z80 kit that supported symbos though. Or at least get the rc2014 to support it.

[@LucasHartmann]

I was wondering if you could use a linear feedback shift register in software as an address counter. It should allow you to cycle over the entire address space (except zero) by shifting just one address bit per data word. Granted the hardware SPI would still outpace this bitbanging.

[@DoomRater]

I'd want a tone generator and some form of wireless communication like an IR blaster.

[@absalomdraconis]

Yeah, hang an adder off the clock, route it into a magnitude comparator, set the other number wherever makes sense, merge the "equal or greater" pins into "+=" AND route to the inputs of two XORs. Use the XORs to modify the serial line IO. Maybe use one of the old binary switch ICs to hook the serial between different transceivers, probably an RS232, IR, and audio connector (so amp) at the least. That might be a few many parts though. Maybe on a daughter board instead.

[@KingJellyfishII]

It would be cool if you could somehow add a way to address an SD card kinda like the hard drive in a computer so you can load programs and files from it.

[@perseverance8]

Z80's are still common in numerous industrial instrumentation & control modules even more common than 6502 based modules, from my experience Z80 & 68HC11 based devices are ubiquitous among some legacy MC6800 devices I've repaired to keep in service.

[@njwilksy]

Isn't dead bugging an IC when you flip it on it's back and bend a couple legs down and solder directly to them, leaving it looking like a dead bug on it's back.

[@Roanokekidstech]

njwilksy Yes! This is called piggy-backing! Ben definitely knows the difference just a brain-fart I'm sure

[@njwilksy]

@@Roanokekidstech yeah he def knows the difference,this dudes insane with electronics

[@mywave82]

Eagle can draw line over signal names, prefix the signal name with !

[@jpnc2319]

Would be possible to create a computer with two or four zilog z80 processors and make a 8 bit multitasking system?

[@ctrlaltdude]

Perhaps use the edge connector to hook it up to a keyboard? Then someone could solder a keyboard cable to an edge connector and then plug in the batch pcb into the connector and control it that way. Like those keyboards with an integrated card reader. That tiny screen is a bit small though... I would prefer something a little bigger so that you could really do something with it. You could program some kind of visual demo and display that. Make the holes for the strap conductive so you could use the neck strap as wires (+ and -) to hook it up to a small battery on your back or something. That looks nicer than a usb cable.

[@JanEringa8k]

There are some reasonably cheap serial UART chips in surface mount. Downside is you would need to modify the bootloader to use it.

[@De4thInc4rn4te16]

really nice project ben!

[@TekWit]

Great Job !!! I can't wait for the part 2

[@michaelstoliker971]

Watching this in September 2020 I feel the loss of being able to make plans for large gatherings of people. Did this series ever get completed?

[@chromosundrift]

At 5:20 you say shift registers are attached to the data bus - did you mean address bus? I'm a hardware n00b so I can't be sure.

[@jasonledger6055]

Did someone know the part number of the OR and NOT gates ?

[@GeoNeilUK]

One thing I'd like to see, a Beeb (BBC Micro) on a chip. It's what the BBC Micro Bit should have been. Problem is, the BBC Micro was powered by as 6502 and I don't know if 6502s (or indeed any of Commodore's chips) are still avilable. Also, I'm British, not American and BBC was big in the UK, not the USA, so I doubt we'll ever see it.

[@absalomdraconis]

Pretty sure the 6502 & derived are still available.

[@andymouse]

For what it's worth, I would like that too (Brit)

[@officermeowmeowfuzzyface4408]

Add a V9958 for an RGB gaming output. And controller inputs. And a ROM expansion slot with some memory banking.

[@digimbyte]

it needs a tiny battery for ram persistance

[@TomStorey96]

You CAN put a line over text in EAGLE using the exclamation mark. First one starts the line and a second one will end it, so "!R!W" would have a line over the R, but not over the W, as an example.

[@OmarMekkawy]

What is the program's name used for creating the block diagram @29:25 ? Is that Adobe photoshop ?

[@vinnycordeiro]

I believe it's Adobe Illustrator.

[@thepvporg]

Double sided PCB makes it smaller. I'd say about 2/3rds smaller...

[@GlennHamblin]

I think I would have liked to see it without the Arduino just pure Z80. And a more modern/available smt UART chip. Maybe a bootloader ROM.

[@UpLateGeek]

Can't remember if you mentioned it in the video, but it'd be pretty cool if you could get some sound out of this thing. Ideally it'd be out of an old fashioned sound generator chip, which could generate a few channels of sine/square/triangle waves, but I'm pretty sure these aren't made anymore. I guess a basic PWM might suffice, but it's not going to sound great.

[@scharkalvin]

I don't have any 6850's, but do have a shit load of 8251's. I guess I could use those with a bit of programming change on the Z80 side. There are 64pin versions of the atmega32u with 64k or 128k program space, their pin spacing is the same as the 32u' (those chips are used in the Teensy2 IIRC). So you could use them if you run out of I/O pins. You could also use I2C eeproms and displays. The SPI bus would require one additional (cs) pin per device, while the I2C can address up to 64 or 128 devices without any additional CS lines. There is a 16 bit I2C I/O expander chip, slower than the SPI shift register, but would save a few I/O lines. In addition to the Z80, there is the Rabbit fully integrated part, but I agree with using the 'classic' Z80. I'd also like to see a kit, or at least be able to get a bare PCB board and kit my own parts. Would need a download link for the Z80 code, or arduino INO file. If you could put a microSD card on there interfaced with the Z80, then you actually could have CP/M on there using the micro SD card as a floppy disk. Maybe might have to interface the SD to the 'arduino' and have that chip "dma" into the Z80 memory. But then would need a way to have the z80 talk to the arduino to command the 'floppy'. Maybe via escape sequences over the serial link.

[@ShinyMajor]

Is that a Microsoft Internet Keyboard Pro? I haven't seen one of those in years. Brings back fond memories of being young and exploring the wild west era of the internet

[@laserspaceninja]

Was thinking the same thing! Ben has all of the cool 90s shit in one shot lol

[@bustopherjones2285]

I really hate that they stopped driver support for a lot of their keyboards. I had an Office keyboard from my childhood that lasted forever till it stopped being recognized in windows.

[@FrankenLab]

Where can someone buy one of these kits?

[@SteveRaynerMakes]

What gauge wire do you use to wire the proto board?

[@lindoran]

a RTC would be fun something cheep like a MCP79410? not a whole lot of IO required plus could be dual purposed to output to the Screen and used as a clock.

[@asagk]

Nice. But when I look at the schenatic diagram, I start to believe that an Arduino mega (ATmega2560) might make the better choice as a base system, and the Z80 board could be an addon board to an arduino mega. That would solve all the port issues. The Arduino Mega comes for like $12 from China. So not a question of price tag.

[@MisterRorschach90]

So I keep seeing people making custom sbcs based off of old PCs and gaming machines, could someone make sbc Dreamcast?

[@timtrzepacz3452]

How about adding some buttons so people can write games for it?

[@SteveJones172pilot]

In your decoding of the chip enables for the two RAM chips, do you have to worry about gate delay because the lower enable goes through one fewer gates? If not, why, and/or how fast does a circuit have to go before you'd have to worry about this? Is it that the CPU wont consider the data on the bus valid until after a hold time which is long enough?

[@BenHeckHacks]

The propagation delay is in nanoseconds, not an issue for a CPU this slow.

[@DaveMcAnulty]

What you need is some good ole fashion Destructive BS!! You can get it in Putty by going to Settings -> Terminal -> Keyboard -> Backspace Key :)

[@Xi_Jinping_is_Pooh]

Zilog is still around? Never knew...

[@invers54321]

Great Project. Why not use a 128kb RAM chip (using the lower 64kb) simplifying the memory logic? Another thing; do you really need the MC68B50? Is it possible to make the Z80 speak directly to the ATMEGA emulating ACIA? It would be nice to have an interfacing bus, As you mentioned the RC2014 bus may be too large, but what about a 40pin (2x20) bus like described by Steve Cousins?

[@BenHeckHacks]

I have tried that, it's difficult to emulate peripherals with slow MCU's (16MHz). I will probably use the high speed timer4 to clock the Z80 so it may be possible to slow it down when trying to transit data. What I do, have to be finished in February :)

[@invers54321]

@@BenHeckHacks I am sure it will be a great kit. The 68B50 is very flexible and can run asynchronously to the CPU. I have used it running at 7.3mhz with a Z180 running at 33mhz. I understand you can not be too adventurous with the design when having time constraints. Good luck and i look forward watching your next video. Karl

[@Xoferif]

Using a 128kB SRAM chip would be cheaper, use less board space, and there'd be no need for the memory map decoding - just tie the top address pin high or low.

[@returnofbeaux]

The only thing I could think of was a computer speaker that mutes with a physical switch and only plays passive feedback from board activity. Maybe this would require too much additional parts and research. An audio aspect would give it personality, though.

[@andreaszapfl9776]

Hey Ben :-) Eagle can draw a line above a text. Use exclamation marks in front and after the text: !TEXT!

[@BenHeckHacks]

Awesome thanks!

[@TheeBuddylee]

Code was my favorite part

[@disposablebasterd]

How can we get one of these if we have no feasible way to go there?

[@BenHeckHacks]

I'll put the plans etc on my Github.

[@ColdShoulderMedia]

GBA micro with Supercard Mini SD. Nice choice.

[@berretw]

I love your work :-)

[@josemfacuna6754]

Ben, do you have this SBC as kit? and if you do how much?

[@hafkensite]

Maybe a buzzer?

[@carlossantiago4845]

Add a sound output (single bit pwm).or an spi/i2c DAC with amp and speaker.

[@romiolover6852]

great job but how about adding a usb host ic to connect a usb keyboard and with the oled screen you will have a full computer.

[@gorillaau]

Getting away from the badge concept.. perhaps it could be done via the edge connector?

[@Darryl603]

It should have a pass code for the kitchen service door...

[@1stage]

I think a RAM battery back up and RTC would be worthy additions...

[@guerillagrueplays6301]

I don't know if you still take project suggestions, Ben, but if you do I have a bit of a challenge for you: Retro computing is a huge thing nowadays, with both the preservation of old software and the exploration of old systems being things that gamers and computing enthusiasts are growing to love more and more. There are caveats to that though, chief among them the cost of upkeep of systems and parts (like floppy drives, old hard discs, etc.,) and the sheer amount of space typically required to house the old systems and software. And so, my challenge! You're good with Mechanical Things. You're good with circuit boards and the like. I would like to see you design a DOS gaming computer using modern chips and techniques that's integrated directly into either a 5.25 or 3.5 floppy drive, with the following limitations: --The unit must be designed with software compatibility in mind first and foremost, with a focus on games designed for 486 platforms and earlier. --The drive should be functional, allowing games to be written to and from floppies in a format compatible with classic DOS computers. --Despite being designed with a focus on retro software, the hardware support should be relatively modern: USB mouse/keyboard, VGA or better video output, etc. --Size matters: while the unit doesn't have to be as small as, say, a Pi, it should be kept as compact as possible while still maintaining the features above. I imagine the hardest part of designing something like this would be sourcing the floppy drives themselves, or parts to build your own, but such a thing would be *incredibly* handy to have, both from a computing and a conservation perspective.

[@Yuonfjddsxhkhfgfok]

hi mate could you plz tall whats software are you using in this video?

[@lucianostech]

You rock!

[@chromosundrift]

12:02 Ben: "In an effort to see how boring I can make this video, let's go over THE CODE" Me: "oooh here comes the good bit!"

[@mekurri2007]

so jealous about the MGC lol, if only we had teleport/cloning terminals already

[@robertofavila6494]

What gauge of wire do you use ?

[@JesusisJesus]

The disappointment you feel when Ben Heck can Dead Bug a ProtoBoard and it has more memory than your Commodore 64 @ 26:23 :(

[@ithaca2076]

I agree Jesus.. I pray for more memory

[@dj68k]

I want to plug the edge connector into my C128 and make the two Z80s fight.

[@davegnx44]

Maybe io pins for an FPGA might be interesting

[@LittleRainGames]

Why not use AT90USB1286, they are a bit more expensive than 32u4, but more IO. Could also use SamD21J18, 32bit and is arduino compatible.

[@BenHeckHacks]

This is intended as a kit so I needed an MCU that is possible for surface-mount-soldering novices to accomplish.

[@greggsenne1268]

Does anyone use wirewrap anymore?

[@lelandclayton5462]

Since you have an edge card platform why not a mini membrane keyboard?

[@diditbreak]

Ben, google 'Konami Hyper Boy'. It's a little bigger than that GB Micro, but it's pretty awesome.

[@christopherkise]

Why so thin leads on the board.. Makes them so easy to breake..

[@jasondahmen4545]

I wish I had as much knowledge as you. Where do you even start, in today's world I can attempt to understand the micro controllers but getting beyond that is tough for me.

[@AllenKll]

If you can understand micro-controllers... you have a huge knowledge base, and a very marketable skill.

[@joshuaupham5993]

Where do I sign up for the workshop?

[@st3ddyman]

Why didn’t you have to worry about the setup and hold timing when writing to ram?

[@BenHeckHacks]

Because the RAM is much faster than the 16MHz MCU.

[@claydonkey2181]

Bit late I know but you can bar/overline a netname to define an active low signal in Eagle: Prepend the name with a bang !. ex CE = !CE

[@shanejohnson77]

Since you're creating a bus, why not use it for sloting a badge for contact "more-information" at vendor booths? Simple readers at the booth can collect "badge" ids and at the end of the convention collect them in exchange for returning a list to the vendor.

[@Pridetoons]

MSX and ZX Spectrum Clone when?

[@vinnycordeiro]

The MSX used the Z80 as well, I believe it's just a matter of finding the correct ROM.

[@AlpineTheHusky]

What wires are you using on the prototype? Im need to buy some and am too cheap to try different wires :b. Only got 22AWG which is way too stiff

[@Dodo-bf3dm]

We need to see hacks that make retro computers compatible with modern accessories! I can't use my Tandy 1000 anymore, 'cause I don't have a tandy keyboard

[@Commander_ZiN]

looks fun