Building and Testing the CB2 Microcomputer

[@cb2micro]

Just a bit of note on your Excellent demonstration! You can use the CALL function to combine programs for a total of 760 lines of BASIC code. And if you write your programs with functions, you can recall them at any time ;)

[@NoelsRetroLab]

Ah! I remember reading something about that, but it makes a lot of sense now. Thanks for clearing that up.

[@angieandretti]

A version of this kit where you could solder-on an optional flash memory chip and easily get unlimited program line length plus program load and save functionality would be really awesome!!

[@raymondheath7668]

Cute little project. I remember Tiny Basic for my Cosmac ELF back in 79

[@garyt123]

Maybe the designer didn't appreciate the difference between DCE and DTE serial devices. DCE devices should _always_ have a female connector, which helps avoid unwanted shorts and voltages getting into the UART. Other than that it looks like a really interesting little build. Great video, thanks!!!

[@cb2micro]

Hi, this is asynchronous serial connection, no clock or handshaking. It was thought as replacing the PC, thus the RS-232 connector is a male one, just like the default on PCs, so you can use standard serial cables to connect other devices that usually have female connectors. That's the only reason for the male connector really.

[@TheSulross]

looks like a pretty good first project for the likes of me - thanks for very informative look at this board

[@cb2micro]

It is dedicated to inexperienced people, thus the very detailed assembly instructions. Half of the fun is to assemble something yourself. The other half is programming it and see it working.

[@JeffreySJonas]

Instead of a DB9 RS232 port, I'd consider a header to a FTDI adapter from the chip's 3.3/5V serial to USB serial port. Draw power from that same USB and it's one USB connector for power AND serial link.

[@annieworroll4373]

That's how the RC2014 works, it also has a jumper to disable FTDI power so you can use a barrel jack, which can be useful if you install a lot of modules on the backplane- you can blow past the FTDI power limits if you do.

[@abcxyz15000]

Great video! Thanks for your content , Noel!

[@olavl8827]

If this thing had USB and HDMI like you said in the conclusion then those subsystems would probably be more powerful and complex than the main CPU itself. Which would be cool, but kind of silly. Notwithstanding that, VGA would have been nice. It would be similar in complexity to the SCART interface, using resistors to divide the RGB signals. It's also a lot more common on modern screens as an interface. This is not the 8-bit modern retro computer of my dreams, but it's seems like a nice project.

[@NoelsRetroLab]

Good point. Although sometimes we end up with mixes like that in retro computers (an FPGA chip replacement that is more powerful than the whole computer). After having played with this, I would definitely take the extra complexity of USB (or, if it's simpler, an SD card, but I think that's even more complex).

[@cb2micro]

@@NoelsRetroLab I tried not to include any extra chips for the project, but just a low cost general purpose MCU for various reasons (an SD is an extra chip after all). One is cost, as I wanted to keep it as cheap as possible for people not to hesitate to buy it. Another reason is that I wanted to keep it as retro as possible, so people can live the experience of such a retro micro. Another reason is future availability of components, a low cost general purpose easy to solder DIP MCU that could probably still be found after a few decades. These ports can be thought as obsolete by today's standards, but there are numerous of times one may need to control or test retro devices like serial modems, or parallel printers and these old ports have looong gone on PCs, so the CB2 micro is an alternative way of doing it. I know at least one guy that has used it to debug the serial data in his low altitude balloon!

[@ian_b]

@@cb2micro I think you were right to do it this way. You've stuck to a hardware philosophy and that matters in a project like this. Nowadays, you can always add more, but as you do so you add complexity and cost which destroys the original idea.

[@cb2micro]

@@ian_b Exactly. The point is to keep the thing as hardware simple as possible, which of course make it as cheap as possible and as easy and quick to built as possible. One might think of 100s of extensions to build. Even usb connection is super easy with serial to USB chips. I did not want to add more chips to it. It is better for one to buy a super cheap serial to usb adaptor and use it for any other project they might have instead of increasing the cost and complexity of adding another chip to the KIT. Cause, consider if this KIT was for 50E, would you buy it? That's the point...

[@ian_b]

@@cb2micro Thanks for replying! One other thing, I personally find this design within constraints very interesting as it gives us a greater insight into general product design, especially regarding the microcomputers of the past when options were much more limited and machines from the likes of Sinclair, Commodore etc had to be built within a target price, and every logic gate and transistor mattered.

[@JohnSweevo]

That wee thing rocks, must get one Thank you for this video Noel

[@NoelsRetroLab]

You're welcome!

[@bondjovi4595]

This really should be the next big internet thing.

[@luisastorri8824]

Gracias por sus videos. Muy interesantes!!!

[@chainq68k]

Nice build and review! On Amaz*n (and elsewhere), they actually sell 9 pin "null modem" gender-changers. So a 9-pin gender-changer, but with the Rx/Tx pins swapped, so two ports with male connectors can talk to each-other. You just have ti pick the female-female variant of the adapter. We use them at work, they only cost a few EURs per piece. They're usually marked orange, rather than the normal blue color of the "straight" gender changers. They're perfect to connect embedded hardware with a serial port (which this essentially is) to modern computers using these cheap USB to serial adapters.

[@NoelsRetroLab]

Yes, I even ordered one of those, and when I got it, it turns out it was the male-female one, which doesn't do what I need. Maybe I'll do a followup video when I get the right adapter :-)

[@MacBerti28]

Great video Noel! I would recommend you getting a normal pin-to-pin gender changer, there's no need to change the type of your cable. You can configure the cable type by closing either jumpers J5 and J4, or J3 and J2 on your CB2 micro.

[@NoelsRetroLab]

@@MacBerti28 Right. I'll order one of those today. And it sounds like I should definitely do a followup video with the results and a few other things. Thanks!

[@EduSodap]

Great video, I might even get this thing

[@unebonnevie]

Now Microchip, after acquiring Atmel, makes the microcontroller family AVR128, which has 128KB flash size and 16KB of SRAM built in! This comes as 28 pin PDIP, 32 pin TQFP, or 64 pin. All run at 24Mhz!

[@ElectronGordo]

Hello, very interesting, about CB2 and its Scart connector... looks nice but not reliable, it has not a shield connected to connect to ground, what could result into parasite signals. Nice video, nice page to follow, and I love how they write into the PCB the values of the components instead the number of it, it helps for future changes or/and repairing to know what was there without needs of Internet or anything else. Also ... wonderful idea about the resistors!!! I will take it for my own boards. Lot of stuff for learning from your video and the site! thanks Noel

[@NoelsRetroLab]

The idea of the labels with the values is to help beginner users, but I'm not a fan of that. First of all you need more room for them to be readable, and then, it makes it impossible to refer to a particular component on the board if there are more than one of the same value. Using the normal method you can say "replace R7 with..." but here it's much harder. Interesting about the SCART connector. The internal ground connection isn't enough for that then? You would need the outside to have a metal shield and connect to the ground on the PCB?

[@ElectronGordo]

@@NoelsRetroLab Depending on some factor, in our systems, we'll needed it, in other way it works like a capacitor and create a parasite signal due to the Vpp (electrostatic and the shield of the TV), sometimes one of them need to be not connected (mostly GND joins), it is a bit complicate for me to explain, in few words, the TV and VideoGames industries put them (with the cost of this material)... must be for a good reason. 2 of them... parasite signal and current parasites, keep in mind... the cable itself is an ant, and has not a capacitor or a load at the end cause not a shield or connection to GND in the other device, so... the emitter also receives part of the energy that transmit... that's not good. My memory is not so good nowadays, hope you can understand what I tried to tell

[@MattKasdorf]

@@NoelsRetroLab Labelling values is an excellent PCB design feature and it's a shame you do not like it. If you don't have or can't find a schematic for your repair the silkscreened value is invaluable. It is not a feature just for beginners... just ask Dave at EEVblog.

[@NoelsRetroLab]

@@MattKasdorf Couldn't you just read the values from the components themselves? And how do you even tie the specific components in a circuit diagram to the specific ones on the board? Without some kind of C1, C2, C3 labeling you have no way of knowing which one that is. Now if we're talking about having both markings and they fit, sure. But still, if I can only have one, I'll take the component identifier.

[@cb2micro]

@@NoelsRetroLab I thought of the beginners when doing so, like you said. Some people are not reading the instructions, so go directly in soldering. Not a good electronics practice to have the components values for sure, but just a help for beginners or if the schematic is lost after many years. A failed component for example where you cannot read it's value would be a nightmare to repair after decades. That sort of things basically...Again a decision not optimal, but it might worth it in such cases. BTW, I have not found any interference problems with the scart, maybe if you use it in an industrial environment, but never tested it that way.

[@beforth]

The board does have the 5v RX/TX pins next to the crystal, just connect a USB to TTL serial adapter to those pins and you should be able to communicate with the microcontroller. The RS232 connector and related voltage conversion components are not so useful nowadays, and they make the board bigger, more complex and more expensive.

[@cb2micro]

It offers both UART, like you mention and also RS-232. Remember the CB2 micro is designed to be a retro computer, meaning that it has to control retro devices, serial modems, parallel printers etc. It is designed to give you the feeling of how it was back then, without breaking your pocket. In fact there are numerous of times one may need to control or test such devices and these old ports have looong gone on PCs, so the CB2 micro is an alternative way of doing it.

[@justingreen8006]

I never heard of SCART before I just looked it up now. I'd take that SCART connector and toss it as hard as I can into the woods.

[@mheermance]

I'd heard of it, but never seen it used. Given that it is priced in Euros it's probably a European standards.

[@eekee6034]

I love circuit schematics. :) I think it's nice that it has the values on the board. Despite the small text, it would still be better for me than the extra step of value -> number -> board. Bytecode was sometimes used as a memory-saving technique in the 90s when RAM was more expensive than CPU power. A 20MHz CPU with 4K RAM is exactly the sort of machine which would benefit from that. I guess the BASIC is kind-of that already. I'm aready getting ideas for lifting the editor's limits. :) Virtual memory is easy when you're single-tasking, or cooperatively multi-tasking. Actually though, it might be hindered by the slow write speed of Flash.

[@pareshmhatre4019]

Good information!

[@Xoferif]

I think this would be a good gift for an older child to give them confidence that they can assemble their own computer. For learning programming, I think a Raspberry PI Zero (for example) would be much better.

[@NoelsRetroLab]

I can see that. One thing I like better about this is the instant-on quality of it, just like the 80s computers. Raspberries tend to have long, laborious boot times (unless we're talking about some custom firmware).

[@cb2micro]

Hi Xoferif. It was not built to compete with raspberry. This is a simple to assemble and operate BASIC micro like the retro ones. This is another thing basically, you can't assemble a raspberry :)

[@SianaGearz]

Being a Harvard architecture processor, the AVR is dissimilar to 8-bit microcomputers, since it's only capable of executing code from ROM. But it is quite fast with single cycle instructions! I think what would make a good single chip microcomputer is just about any ARM microcontroller, like STM32 or LPC series. They are priced lower than AVR ATMegas for the amount of RAM and the speed that you get, they can execute machine code from RAM besides ROM just like a real microcomputer, and they have a DMAC peripheral that can be used to automate video and audio output, so the CPU doesn't have to be occupied to output them, it can just prepare a rolling buffer of several lines to output in bursts, leaving more CPU time for the software. There's also a USB device peripheral onboard, which you can program to emulate a USB to RS232 adapter, all on chip. But of course the real problem with something like this is spawning the ecosystem of compatible software, and i don't think it would just happen like that. This device is however exactly what you'd design about 10 years ago. Also once you get into more modern chips, like ARM micros, they are just not available as through-hole. It's also nice enough for the first time builder that this kit basically sheds and externalises all possible complexity and gets itself down to a bare minimum of components.

[@cb2micro]

Exactly, ARM are not through hole, not user friendly. You got the right point. This simple 8-bit micro is pushed hard, due to the excellent firmware and doing things one would never imagine!

[@paulie-g]

@@cb2microIt's a very cool project. It's a little bit sad that it's hamstrung by AVR's very low RAM sizes and no way to even kludge more in with SPI or like with the RP2040s PIO (never mind STM32's FEXT). Tricky finding a suitable microcontroller if 8-bit is a hard requirement. ZIlog still produces eZ80s, I think, and they've got an external bus, but that's going to be a QFP package.

[@RetroJack]

My only issue with it is the SCART connector - those were never really a thing down here in New Zealand.

[@MisterRorschach90]

They sell modern boards with serial ports for server use. If you wanted to have a decent machine with serial capability.

[@dreamvisionary]

I prefer it when a PCB has the values rather than a component designator, as then you don't need to cross reference the parts list.

[@NoelsRetroLab]

Fair enough. It makes talking about a board harder through ("replace capacitor 22uF...", which one?). In the ideal world it would have both, but then the board would be huge. I guess there's no perfect solution.

[@amirpourghoureiyan1637]

I think a good compromise would be to have the normal labels (R1-10, etc) on the topside and the list of values on the back of the PCB

[@StrapMerf]

The good soldering guide, the pics at least, they look they were pulled direct from the old dick smith funway (no2) to electronics.. so much nostalgia

[@brycelynch2138]

I've been wondering what I was doing wrong with regard to cleaning the flux off of the PCBs I was working on. A rag and scrubbing on top seems like the obvious solution (which is why it's not obvious :) ). I'm going to try this tomorrow - thank you!

[@SeanChYT]

Too many KZbinrs just smear the flux all over the PCB, so it's no wonder many people learn it incorrectly. Thankfully Noel is better.

[@dLLund]

thank you for posting. i looked on aliexpress - qty 2 db9 f-f gender changers for less than 3$us, inc shipping. the rs232 port, instead of usb for keyboard & communication, is probly a function of the microcontroller, which has native rs232 io pins. please take care & stay safe.

[@Stoney3K]

That might not work -- if the CB2 serial port is a 'host' like it is on a computer, you need a null modem cable.

[@MendicantMonkey]

@@Stoney3K He's got another video I haven't watched yet about serial on the CB2, but I'd assume the null modem is the route intended by the designer. Being standards compliant, a host or DTE (terminal) device DB9 serial port should be male, and a device or DCE (modem, printer) device should female. I'm just being specific for the younger crowd that maybe didn't live through the modem era. ;) EDIT: The CB2 has jumpers to configure the port. Noel's follow-up video does some interesting investigation of the options.

[@cb2micro]

You do not need a null modem cable. I have designed the CB2 micro board, so that you can convert any straight serial cable to null modem and in reverse, by just changing the jumpers onto the PCB. The MCU does not have a PS2 if I remember correctly. This is implemented in software (Assembly).

[@Darphi01]

Hi there, Thanks for the great video. I'd like to suggest that you build and show a Colour Maximite 2. They look like a great little 80's style computer but with a fast modern processor.

[@NoelsRetroLab]

Hi Darren. Glad you liked it. The Maximite is already in my list (although I don't know if it's the 2 or not), but the one I'll do before that is the BASIC Engine, which I already have the components for. It's also really powerful, so I think it's going to be quite an interesting comparison.

[@cb2micro]

@@NoelsRetroLab Whereas basic engine is an interesting project, it is based on a modular approach. For example the wireless is another computer inside this computer. In fact you are buying 2 computers not one. When the company stops making these ESP modules, your project is cone. Not an opensource thing! I could have USB, Wi-fi, and so many other things on the CB2 micro, it is very easy. Like people said in above comments, there is a point you have to stop and include the basic things, for the project to be easy, cheap, quick to build. Then people can experiment on extensions and learn things and create themselves. See how much you have learn about RS-232 for example. The CB2 is extensively documented too. The maximite (the older versions that do not use a modular approach but not the new one), is interesting too. Not through hole, but very interesting. More display resolution, but less colors than the CB2. Also much more expensive than the CB2. I do not know how one can decide, I can't decide myself. It is a well built project though, and shares the philosophy of the CB2, in a bit more complex way.

[@alankingvideo]

You could have made the serial (RS232) connection work with your adaptor with possibly just 3 dupont female to female connectors. Pints 2,3 and 5. either straight or 2 tx -3 rx crossed over. 5 is ground.

[@104d_3rr0r_vince]

KOS did a great job.

[@rickdeckard8716]

Cool T - shirt .

[@melanierhianna]

The CB2 is a computer so it has a the computer end connector ie DTE connector (male) rather than the equipment end ie DCE (female). The USB to serial adapter is also a DTE end connector. You need a NUL modem cable to connect the two. NUL modem has two females where the RX on one connects to the TX on the other. And the RTS on one connects to the CTS on the other. As for performance check out a BBC Master running BASIC.

[@cb2micro]

No you do not need a null modem cable. There are jumpers onto the PCB, so you can configure your serial cable as a null modem or straight, by changing the jumpers. But why do you really compare the BBC master with the CB2 micro? They are different things, the CB2 micro is a marvel of hardware simplicity.

[@albertmorris4889]

Null modem adapter/cable. I had to build many of them in the 80s

[@cb2micro]

You do not need that. There are jumpers onto the PCB to do this for you (swap the pairs), and you can use a standard (straight) serial cable instead. This little trick saves you from buying or building such a cable, for the ones that have not one already.

[@DAVIDGREGORYKERR]

I think most terminals are looking for RTS-->CTS and DCD-->DTR for the serial interface to work.

[@tristunalekzander5608]

Sick I didn't know you could self-program with AVR

[@JakeBirkett]

I got confused when you explained the 470 Ohms resistor because you said 4.7 x 100, but brown is x10 according to the chart. So did you mean 47 x 10? (same result = 470)

[@angellaracuente6343]

what is that device you are using on your left hand to remove the solder 9:50

[@zbrnelic]

is it still possible to order cb2 kit somewhere ? i can't find it ... or at least PCB ?

[@AngDavies]

probably don't need the brush to be antistatic, even near pure alcohol is conductive enough that it will dissipate static quite effectively while it's on there. not as good as water, but you don't need that much

[@niranjan9220]

Good sir

[@thomasw2509]

The thing can be build even without using the SCART connector. If someone is interested using the composite video output, let me know. I have modified and build a BC2 using the composite output and making a much more easy to use output , read single pin row port.

[@BurkenProductions]

What lookat the color table for resistors ?? Why?? Easy enough to read in your head

[@Not-Einstein-61]

Thanks for this great video Noel. After checking out the ATmega644p, and seeing its not a CPU, but a MCU like Arduinos and ESP32, can this realy be called a Microcomputer ? Just seems like a big Arduino, the ESP32 has something similar with the LILYGO FabGL VGA32 board.

[@blackterminal]

16:00 to skip the soldering and see it tested

[@NoelsRetroLab]

Good point. I'll add timestamps in the description to help people find the part they're interested in.

[@blackterminal]

@@NoelsRetroLabI liked it all I was just excited to get to the testing. :)

[@michaelstoliker971]

It's always easy to arm-chair quarterback, but I would have started with a composite video/S-Video output on the basic kit and gone with SCART/13-pin RGB as an option. The SCART only option immediately cuts off the possibility of sales to the U.S. Maybe the designer didn't want to be bothered with over-seas sales, but why limit your market? The other change would have been to just go with USB for serial and keyboards. USB to PS2 adapters are becoming as rare as hen's teeth already!

[@NoelsRetroLab]

Agreed. Although for a composite signal you probably need some kind of encoding chip. SCART is straight RGB, which makes it very easy to hook up. But I wonder if HDMI would have been easy to support instead (and it would have freed up a bunch of real estate on the PCB to make easier-to-read labels). And I'm totally on board with the PS2 keyboard, but again, I think that needs a USB-handling chip and one of the goals was to keep size and costs to a minimum.

[@MacBerti28]

The original designer of the "AVR-ChipBasic2" didn't have any sales in mind, this was just his hobby project, so he used what he thought to be useful for his purposes. On an LCD TV you should get a decent picture with a good-quality SCART-to-HDMI converter. The only major drawback for North Americans will be that you can't use the CB2 with a CRT TV, which I prefer for retro computing. BTW, the CB2 micro also has composite signal output, although only in BW, on the two pins labeled "B/W out" and "GND".

[@charlesdorval394]

@@NoelsRetroLab Correct on the USB handling chip. There was (is?) an arduino shield that did exactly that, but the price was quite prohibitive being a Maxim part. Ironically, I have the chip but not the board, thanks to Maxim's sample program I had access to long ago. Sidenote, I'll have to get a good look at that RS232 implementation, quite interesting for those times when you can't get a MAX232 or the like.

[@cb2micro]

It DOES have a composite video on board, but it is grayscale. If you want color composite you could build this little extension cb2.qrp.gr/extensions/#8_Color_composite_videoS-video which I have tested and works perfectly.

[@tho_tho]

For a moment I thought you were from Greece looking at the Greek on the package, then I paid more attention and realized that was FROM Greece, I guess I'm blind! Just one question though, do you always put the frequency crystal that close to the board when soldering? I've had a bad experience from when I was starting out years back when I put it very close to the board so when I went to solder it I accidentally overheated it (340°C and slow hand) and it ended up malfunctioning from it, so I tend to always just put them sticking out at least half a cm from the board.

[@NoelsRetroLab]

I didn't think much about the crystal. I haven't had any bad experiences with it yet, so I never thought to keep it further out. Now that you said that, I'll probably try to leave a bit more distance though. Also, I normally keep my soldering iron between 300 and 320°C, so maybe that's helping prevent some damage. Thanks for the tip though!

[@tho_tho]

@@NoelsRetroLab I also go with 320°C nowadays, but I used to keep mine a bit hotter at 340°C only because that's what professors suggested during lab experiments in my first year, which thinking about it is a bit higher than you should for these delicate components.

[@NoelsRetroLab]

@@tho_tho I keep the temperature at the lowest point that comfortably melts the solder. When I was using worse quality one, I had to have it around 340-350, but the one I've been using for a while melts like butter at around 320C.

[@frozendude707]

:o a retro computer nerd that does not have a nullmodem cable, the shame :P

[@NoelsRetroLab]

Haha, guilty as charged! I did have a couple of them but threw them away in the last move years ago ☹️

[@frozendude707]

@@NoelsRetroLab aw, how sad ☹️ But maybe I am the weird one for living in a 12m² apartment yet having a USB to serial and parallel with null modem and laplink cables within easy reach, yet nothing to connect them to. 😬

[@williammckeever4790]

Great build! Nice to see even a Pro can make a mistake once in a while. Interesting project at a very reasonable price, just not sure I could ever find a use for it but looks like a fun project all the same. Great way to kill an afternoon for anyone stuck at home right now for sure. I have heard of tiny basic before (never used it myself) but wow i'm impressed with what it can do, will have to take a closer look at that. Stay Healthy Everybody!

[@NoelsRetroLab]

Haha, I wouldn't say I'm a pro, but everybody makes mistakes. The pro just sees them more quickly and fixes them :-)

[@annieworroll4373]

SCART seems an odd choice, if they wanted it still retro adn ruled out HDMI... VGA would be more widely accessible, though I don't know how simiple either are to integrate into something like this. VGA might have noticeably increased cost.

[@toastyPredicament]

Could I get some of all that too?

[@andrewdunbar828]

"Retro" doesn't actually mean "old" but more like "old fashioned" or "outmoded" so something can be brand new and still be retro. I call stuff like the Spectrum Next "modern retrocomputers". It's not just computers either. Look at the Plymouth Prowler, PT Cruiser, Chevrolet HHR, and a bunch of Japanese cars from the '90s like the Nissan Figaro.

[@d.j.peters]

The most time the MC will generate the Video signals so how many speed of the 24MHz are left for your BASIC program maybe 4-6 MHz ? (You would learn much more with a retro CPU on a breadboard with data and address bus and connect RAM,ROM,I/O,VDC etc. chips and do all the address decoding and timing)

[@cb2micro]

It's a different story. The purpose is not to learn the internals of a computer, but to learn how to assemble a kit, get your hands on soldering and building and use what you have made to take your first steps with a simple programming language.

[@jurgenpitaske3820]

I could not find what the kit costs?

[@scottlarson1548]

This is kind of the thing I've been thinking about, a simple microcontroller with video output, but the I/O limitations turn me off. I'd want something that I could connect to a Linux machine through USB to quickly copy programs over and possibly design circuits around like extra memory.

[@cb2micro]

It is easy to connect it to a linux PC with USB. Use a serial to usb adaptor, or alternatively build one yourself. Microchip has chips for it, plus drivers for windows and linux if needed.

[@petermuller608]

Use any microcontroller with integrated USB like SAMDx1 or RP2040 ;)

[@reinoud6377]

Why did they choose the 644 and not the bigger ones?

[@MrGeekGamer]

Is it really necessary to clean the flux? I've seen this done before, but is flux really so corrosive?

[@NoelsRetroLab]

Supposedly it can be. It may also lead to some current going between pins, so by removing it you're insulating them better. Last reason: It just looks ugly :-)

[@charlybrown9024]

Yes. The 8-Bit Guy has a video about mounting a kit similar to this one, he had some issues when he turned it on and those issues disappeared when he cleaned the flux residues on the board.

[@cb2micro]

If you use NO-CLEAN flux solder, you do not have to clean any flux. It depends on your solder type.

[@mannhansen9337]

It's mandatory to remove / clean the residual flux. Over time the flux may act as a capacitor and short high frequency signals etc and cause strange issues and problems. Use some kind of rubbing alcohol or technical alcohol. NOT acetone. My background and education is from military electronics and weapon systems. Not removing flux would mean to fail an exam or test.

[@ITGuyinaction]

👍 👍 👍 👍 👍 👍 👍

[@corvusferox2869]

Hey Noel, sorry to ask this out of any reasonable question, but where is the song from 7:35min from? thanks in advance and greetings from germany ^^

[@NoelsRetroLab]

I already answered in the other video, but I'm replying here just in case someone sees the question later on. It's opengameart.org/content/theme-song-8-bit and I added it to the description as well. Cheers.

[@leglessinoz]

What's with the SCART connector? Virtually nothing these days has one of them.

[@NoelsRetroLab]

I don't mind it because my primary retro screen uses it, but I agree it's a really odd choice. Maybe a way of cutting down costs since outputting a VGA or HDMI signal might involve more components.

[@SeanChYT]

To be fair, the problem with the serial communications were not the fault of the CB2. You just didn't have a null-modem cable. A USB to serial adapter like that doesn't give you a serial cable. It gives you a serial PORT. If you didn't have a SCART cable, you would struggle with the video as well. Still not the CB2's fault if that were the case.

[@Sypaka]

You still could have connected the CB2 to the PC using your USB-to-RS232 adapter, you just needed either a gender changer or a Nullmodem-cable, which has female-to-female plugs by default.

[@drtadjakaroghli6898]

El atmega viene programado? the atmega is programmed?

[@NoelsRetroLab]

Yes, all ready to go! :-)

[@drtadjakaroghli6898]

@@NoelsRetroLab pero los fuentes o binarios para programarlo tu están disponibles? but the sources ir bin to program are available?

[@NoelsRetroLab]

Sí, están todas en la página web del proyecto.

[@blackterminal]

Can you add more ram?

[@NoelsRetroLab]

Not easily. It's built into the ATMega, so you either have to change it or come up with some expansion (and I don't think the communication with the ATMega could happen fast enough). So probably better to add a new microcontroller (and new firmware).

[@tenminutetokyo2643]

Someone should make a version which plugs into the C64 expansion slot.

[@SimonEllwood]

4K SRAM is the big limit here. Not adding a USB to serial converter on board is also a shame CH340 chip costs less than a Dollar!

[@NoelsRetroLab]

Agreed on both counts. The USB chip would add more cost and footprint (even as SMD), which go against the goals of the project, so I get that even if I would prefer it with USB support.

[@SimonEllwood]

@@NoelsRetroLab You can use an SO8 to DIP8 adapter and supply it presoldered. You would then not need the RS232 connector so it would not add cost.

[@another3997]

@@SimonEllwood Whatever a project comes with, you can always add something else for "just a bit more money". But you have to stop somewhere, otherwise it soon spirals out of control. There are undoubtedly other projects that provide what you want.

[@SimonEllwood]

@@another3997 Agreed, there is always a balance to be made. An option is to just add the footprint on the PCB and allow people to add it if they want. This was the route followed on the Spectrum Next.

[@semibiotic]

That, probably, would be more useful as video-uC or terminal for DIY micro-computer ...

[@cb2micro]

That IS a microcomputer. Which of course can be also used as a terminal (cbterm) for your other microcomputer.

[@semibiotic]

@@cb2micro Yes, but pretty useless one, without software.

[@cb2micro]

@@semibiotic There is a terminal program called CBterm. you use this on the CB2 micro to communicate with your other computers through serial. Just like you would do with a PC and a terminal program.

[@manuellor3922]

Noel's Retro, do you live in Spain? 0:27

[@NoelsRetroLab]

Yes, that's a pretty good hint right there :-)

[@manuellor3922]

@@NoelsRetroLab Podrias hacer algun video en español. Nice job!

[@gchron78]

Hello from Greece :-) I show that the computer was from here! I haven't heard it. Nice channel I like that we can see something like Adrian's Digital Basement that is more europe centric with technologies like PAL SCART not used in the US.

[@blackterminal]

Can you program in another language to get more than 99 lines in one program?

[@NoelsRetroLab]

You can use assembly language, but I haven't tried that yet. It requires doing it on an external computer and uploading the binary.

[@blackterminal]

@@NoelsRetroLab oh cool. Does it produce spectrum level sound effects or slightly less?

[@cb2micro]

See my top comment. You are not actually limited to 95 lines of code like the video says. Noel knows that by now ;) You can use the CALL function to combine programs (total 8 programs) for a total of 760 lines of BASIC code. And if you write your programs with functions, you can recall them at any time ;)

[@frankowalker4662]

Great vid, I clicked on the link straight away to buy one. BUT, I can't find anywhere to place my order. Can you help? I'm obviously not seeing something.

[@NoelsRetroLab]

I'm guessing he doesn't have an online purchase set up. Just email him or even Paypal that address directly and you'll be able to buy one without a problem.

[@frankowalker4662]

@@NoelsRetroLab Tried the email me link but I can't do anything with the photo it shows me. Thanks for the help. Loving your vids. Stay safe.

[@NoelsRetroLab]

If you can't get in touch with him for some reason, let me know and I'll get you two in touch. Hopefully it went through and you'll get you own CB2 kit soon :-)

[@frankowalker4662]

@@NoelsRetroLab cheers. I'll just keep checking the website from time to time. I don't know how to use email, never had any need to. It might be out of stock.

[@NoelsRetroLab]

Talk to @CB2 Microcomputer directly (he's replying on this thread). I just don't think he has an online ordering system yet unfortunately.

[@dreamyrhodes]

HDMI costs license. Better would be Displayport.

[@retrogamestudios6688]

Cb stands for?

[@DominikKristen]

Chipbasic

[@retrogamestudios6688]

@@DominikKristen thank you very much you Dominic

[@anonanon5146]

CBT microcomputer

[@lachee3055]

looks like a awesome kit but that manual is down-right unreadable for anyone who is slightly neuro-divergent.

[@nosville22]

the nanocomputer if you will

[@SlavTiger]

If only it weren't limited to 99 lines

[@cb2micro]

It is not limited to 99 lines. Noel has corrected and commented this in his other videos. You can use the CALL function and extend your program up to 760 lines of basic code, split into 8 programs. That's a lot of basic code.

[@rondlh20]

Fun, but 4K of RAM, that's a pity!

[@NoelsRetroLab]

Absolutely!

[@another3997]

That's 3K more than my ZX81 had, at least until my parents also bought the 16K Ram pack. 😁 I think the Commodore VIC 20 came with 3.5K. Sometimes it's good to have limitations and restrictions... it (hopefully) forces you to try different things and work out what is more efficient.

[@cb2micro]

It certainly does not match the modern boards like xxberies etc. It is not designed to compete with modern devices and it is of no use if one thinks like this. It is designed to be a retro micro, with all the limitations which this poses. But it is a kind of mixture, so 16 foreground and background colors and many more using the dithering technique ( see the latest game cb2.qrp.gr/programs/#2.9_RainbowRunner ), as well as the CPU speed, are things one wouldn't even dream in the early 80s. So yes, a kind of mixture.

[@tenminutetokyo2643]

Open Source this, Open Source That.........

[@cb2micro]

How else would one could build this in 20 years from now...!

[@petermuller608]

While I really like this product in principle, how can this be sold containing leaded solder? This cannot be RoHS complaint. Moreover this is completely unnecessary, since lead free HAL cost practically the same O_o

[@drcl7429]

You really don't have a standard DB9 cable that you could have connected to your USB-RS232? Disappointing.

[@ImaginationToForm]

99 lines...What an odd limitation.

[@NoelsRetroLab]

I suspect it's because of the 2KB of SRAM. 100 lines x 20 chars per line and there you go.

[@ImaginationToForm]

@@NoelsRetroLab Ah, thanks.

[@cb2micro]

See my top comment. You are not actually limited to 95 lines of total code like the video mentions. You can use the CALL function to combine programs (total 8 programs) for a total of 760 lines of BASIC code. And if you write your programs with functions, you can recall them at any time ;)

[@mohinderkaur6671]

That SCART port . There needs to be a version with standard VGA output.

[@petermuller608]

I'm not sure if you have though that through;) VGA needs a resistor network and is quite complicated to drive. There's an ESP32 software Implementation, but that's an 32 bit processor running at 240 Mhz

[@mohinderkaur6671]

@@petermuller608 Also needs a faster CPU due to higher bit clock of 25mhz

[@mohinderkaur6671]

@@petermuller608 Yes I under stand, but that scart port is utter garbage. a regular NTSC composite would have been ok.

[@petermuller608]

@@mohinderkaur6671 depends on the market. This product seems to be EU centric, this scart. But I agree, for other markets different connectors would be preferable:)

[@CasperUK31]

Think I would much rather buy the cheapest Rpi and get a BBC or C64 emulator on it. This has some baffling decisions.

[@cb2micro]

Exactly. Buy, not build/assemble yourself. This is a totally different approach, they are totally different things targeting different audience.

[@captainboing]

Wait, what? This is 2020

[@another3997]

I'm fairly certain most viewers will have been aware of the date. Did you actually have a point to make, or have you just come out of a long coma?

[@captainboing]

@@another3997 heh... You made this didn't you? idiot

[@aldob5681]

avr is doomed and the price of the kit is doubled at this time

[@seanvogel8067]

I don’t think HDMI is practical…😬

[@BurkenProductions]

Clean Flux wtf no need to

[@kulicher]

Too sad for computer. 64kb ROM and 4 kb RAM. No extension. Useless. Omen Alpha - real computer and easy bild )

[@NoelsRetroLab]

I wouldn't say useless, but very limited. It's also really cheap and really easy to build, so it's a trade off. I didn't know about Omen Alpha, but it looks quite interesting. Added it to my list. Thanks!

[@cb2micro]

Omen Alpha is NOT a complete micro. There are dozens of such serial based computers on the internet. They just require a terminal to operate and do not support color. CB2 micro is a COMPLETE standalone basic microcomputer, like these of the early 80's, made with 1 chip only, a modern low cost MCU, which does not require any other terminal or PC to operate. This is a major key difference. There are others.

[@stefans8325]

I hate KZbin deleting all my comments because of linking to the project. I think the (E)Uzebox a project I tried to link to uses nearly same hardware but having better software with better graphics and sound.

[@NoelsRetroLab]

Thanks. I'll definitely check it out.

[@ladronsiman1471]

it it had hdmi /then the cost will $100 more ...