Tindie

Name: SC126 Z180 SBC / Motherboard Kit
SKU: 17487
Price: 62.00 USD
Availability: InStock
Rating: 4.88 (67 reviews)

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SC126 Z180 SBC / Motherboard Kit

(67 Reviews)

An expandable Z180 motherboard supplied with RomWBW (including CP/M)

Designed by Stephen C Cousins in United Kingdom

2019-07-15T16:51:05.728Z-SC126 v1.0 Assembled - 3x2 - 3048x2032.jpg

2019-07-17T07:56:00.455Z-SC126 v1.0 Accessories - 3x2 - 3318x2212 - with label.jpg

2019-10-22T08:42:41.488Z-SC126 v1.0 Kit Boxed 2 - 3x2 - 2935x1957.jpg

2019-07-15T16:51:05.728Z-SC126 v1.0 Kit Contents - 3x2 - 3729x2640.jpg

2019-07-15T16:51:05.728Z-SC126 v1.0 PCB Image - 3x2 - Green - Top.jpg

2019-08-13T10:57:41.208Z-SC126 v1.0 PCB Image - 3x2 - Green - Bottom.jpg

2019-10-22T08:53:17.705Z-SC126 v1.0 In Use 2 - 3x2 - 4134x2800 - a.jpg

2019-10-22T08:53:17.705Z-SC126 v1.0 With 2 FTDI modules - 3x2 - a.jpg

2019-10-22T08:53:17.705Z-SC126 v1.0 In Use - 3x2 - 3719x2479 - a.jpg

$62.00

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SC302 Serial to USB adapter*

SC303 Micro SD card adapter*

SC305 Adapter cable, 6-way, 8"/200mm*

SC306 USB cable, A to mini-B, 18"/500mm*

For more accessories, search Tindie for "Components for RC2014 and Z50Bus"

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An expandable Z180 motherboard supplied with RomWBW (including CP/M)

The motherboard kit comprises parts to build a Single Board Computer with these main features: Z180 CPU running at 18.432 MHz 512k byte RAM 512k byte Flash containing RomWBW 512k byte Flash contai...

Documentation

The documentation can be found at www.scc.me.uk

Dimensions

The assembled kit is approximately 10cm (4") x 17cm (7") x 6cm (2.5"). It is supplied in a box approximately 23cm (9") x 16cm (6.5") x 2.5cm (1") weighing about 300g (0.7lbs).

SC400 series I2C modules

Notes

This product is supplied as a kit of parts that require assembly.
It is your responsibility to pay any import duty or taxes charged by your home country.
This product is designed for hobby use and is not suitable for industrial, commercial, or safety-critical applications.
RC2014 is a trademark of RFC2795 Ltd.
ROMWBW is copyright Wayne Warthen.

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Review Breakdown

Average Ratings

Product: (4.00)

Documentation: (4.00)

Shipping: (4.00)

Communication: (4.00)

Ed | May 14, 2021

Great lockdown present for self!

Quality PCB, no missing components and even a choice of connectors provided.

Worked first time, online documentation is very good.

Delivered quickly.

What more can I say? If you need a CP/M machine in your life and know which end of a soldering iron gets hot, then this is probably the one you need!

Richard | April 6, 2021

No complaints whatsoever

The sc126 motherboard is a great kit. All the parts clearly identified and I had it up and running within a few hours. Lots of great CP/M options to work with and the 2 on board Monitors work very well and are very useful with built-in help information. I have constructed a parallel ports interface for my own projects which works now and I still have to check out the many options and projects available which work using the I2C ports supplied as extras. Lots of fun so far!
Thanks to Mr S.C.!

Bruce | March 27, 2021

SC126 Z180 SBC / Motherboard Kit.

Great kit!
It did take some time to locate all of the documentation to do the following:
- Locate driver for serial port FT232R USB UART FTDI at nematicslab-dot-com
- Create a C: drive for an 8 megabyte CP/M partition

Performance
Disk speed is very good, as is the 18MHz Z180.
Lots of disk space to work on assembler projects

Future Extensions
OS
I plan to create MP/M 1.1 & MP/M 2.1 OS allowing up to 7 consoles/users to demonstrate pre-emptive, real-time, multi-tasking conditions found in 1980s systems such as the Altos 580.
Hardware
The expansion bus will be used to add various floppy & SMD drives as well as serial, parallel and general purpose interfaces.

Summary

Well designed & executed Z180 kit with excellent performance and room to expand with additional hardware & software applications.

Roger | March 8, 2021

Great kit, both to build and use

Excellent construction instructions and documentation about the card.
Had a wonderful and relaxing time building it, and then starting to play with it.
Very happy with it.

Vladimir | Jan. 29, 2021

Great DIY computer kit

Shipping was fast, despite COVID-19 situation. SC126 (small computer 126 i think) very smart designed and easy to assemble. Documentation written own by Stephen is comprehensive, easy to read (even with my skill, ha ha). I highly recommend this kit for purchase.

James | Jan. 19, 2021

Great kit!

This was a very easy kit to put together with clear instructions. I had it assembled in an hour and a half, and it worked the first time! The board is silkscreened on BOTH sides and you could put it together from that information alone. The more in-depth operational info is on Stephen's website - everything is there, if a little scattered. It took a month to ship from the UK to the USA - I was starting to worry, but it finally arrived in good shape.

Pavel | Jan. 16, 2021

Completely great product

Order without problems. Shipping was very fast (to Czechia). SC126 is very good product - hardware is smart designed and software is excellent (RomWBW). Documentacion is also very good, I would invite user manual in PDF format. Thanks to all for my silicon honey.

Michael | Jan. 13, 2021

Great hardware kit - very, very complete

Easy and simple build, documentation was fair and aimed at people with little experience. Would have been nice to have a summary of all the IO addresses in the documentation. Otherwise, a good kit.

Andy | Jan. 1, 2021

Great kit, fast postage, great support, many thanks!

I bought this to learn Z80 assembly - something I failed to do when I was younger with my ZX Spectrum, but always felt it's something I should return to now I know a little more about how things work ;-) The quality of this kit is fantastic - really good instructions to follow, great support materials with the schematics, board layout and firmware source all easily available. Plus, plenty of explansion and development available to go beyond the board in the future.

A couple of suggestions for Stephen:

(1) a "getting started" guide which takes you through accessing the onboard peripherals. I'm aiming to drive a TFT LCD through the SPI and I've been digging around the documentation a fair bit to find out how to access it and drive things like the CS. All part of the learning though!

(2) provide a header for the 8 output LEDs, so it's easy for them to drive other things. I need an extra output pin and I've ended up using the I2C port's SCL but it would have been easier to have started with the LED output port.

Thanks again for a great product - really enjoying my return to the Z80 :-)

Mark | Nov. 25, 2020

SC-126 Z180 SBC and SC-129 Digital I/O Kit

Thank you Stephen! Great quality kit. Really like having CP/M 3, MBASIC and the Z80 Assembler all working on one small portable and reliable board. Love the RTC feature and using the Micro SD adapter with my 16GB card on the SPI Card SD 1 port works great. Looking forward to using the I2C port with a PCA9685. I'm using the USB serial adapter on Serial Port A which works really well, could not get USB Serial Port B to work, probably something I am not aware of and not the fault of the board, any tips would be appreciated. Your online detailed instructions were excellent, especially the recommended steps to check my assembly work of the board(s) before powering up. No missing parts, packaged and labeled well. The only issue I had was having to lightly burnish the land patterns on the board (and some of the edge connector pins) for better solder flow. Also, I built the SC-129 Digital I/O card which is working great as well, having 8 LEDs for both the input port and output port is a nice feature and the edge connector with both input and output pins exposed is what I plan to be using for adding external hardware like sensors etc. All in all a great kit, would definitely recommend for any one who likes to build hardware and use multiple programming languages for the Z80 processor. Thanks again!

John | Nov. 20, 2020

Excellent Kit and Seller

Well packaged, fast ship, PCB of excellent quality and well marked component ID/values, as are all parts supplied. On Line documentation is excellent, even for a novice constructor (but previous soldering experience or practice would be helpful, considering the close pin/pad alignments). Highly recommended.

Jeremy | Nov. 11, 2020

Fun retro-computing project

Even as someone new to soldering it was a breeze to put this kit together thanks to the excellent documentation and information available on the Small Computer Central web site. In fact my biggest mistake was inadvertently switching the 74AHCT139 and 74HCT138 ICs around in U4 and U10, which resulted in a very unhappy Z180 CPU. After sourcing a replacement CPU the system booted up just fine and appears to have suffered no ill effects. The size of the parcel was a nice surprise - it's amazing how Stephen managed to fit everything in such a well layed out yet modestly sized parcel which should fit most mailboxes. I've since then ordered the SC131 which I finished assembling today - it booted up on its first try!

Alexander | Nov. 9, 2020

Really cool product

Soldered the kit in 4 hours, runs immediately despite my incredible soldering competence. Included ROMs have lots of good software to get you started quickly. The expansion possibilities are enormous due to the many slots.

Javier | Nov. 7, 2020

This kit is the best way to jump into the world of Z80.

Simply put, SC126 SBC kit has all needed, both for hardware and software tinkerers. The kit design is easy to follow and understand, the BOM has quality parts, it’s a pleasure to solder in the high quality PCB. The parts are carefully packed in the box, not a single pin was out of protective foam.
The firmware is just impressive, kudos to Stephen C. Cousins for for including such good software in such a small space.
The kit has SPI, I2C, serial ports and a backplane with all the Z80 address, data and control signals, so you can expand the system to whatever yo need.
So, if you want to learn and practice Z80 assembly, basic or C, this is the kit to go.

Boban | Oct. 29, 2020

Perfect.

Perfect kit in every way - beautiful "motherboard", package, delivery, documentation, fun to build, fun to use. Just perfect.

Angus | Oct. 27, 2020

Excellent delivery considering the pandemic

I ordered on the 8/10/2020 and it is here in Oz on 28/10/2020 .. so 20 days. Australia Post complains of being snowed under so not known how long its been in Oz.

Have checked all the kit. It looks complete. Was very well packed.

Now I have to read all the documentation and stuff online before I hit the soldering iron.

Thank you Stephen.

Update. Even though I have had the kit from November, I finally finished it over the weekend. It works perfectly. Some of my friends say I am too cautious. I don't understand people who get their kits and have them running in an hour or so. Where is the pleasure in that.
I made one change - there was mention of large blue boxes elsewhere relating to this. When I worked with them, red lights meant the power was on or available and a yellow (amber) light said that your day had completely changed direction, so drop everything you planned to do. So I have a red power on light.
The documentation was overall, pretty good but a little mixed up in what could be done with no power, power with no chips and power with the chips inserted. Once you got to the latter stage it was either running or not. SUCCESS - mine ran.
Now trying to figure the instructions to have a CP/M/MSDOS combination on the SD card for easy file transfer.
I have a Linc80, so have a heap of CF cards for that so am going to get a CF adaptor for the SC126 and see what I can do.
Overall, an excellent kit. Thank you to all concerned with its design and implementation.
The CF card kit went together easy and is working fine. Seems to be a lot less fussy than the Linc80 re CF cards, though still only works with smaller (?) CF cards. It did not see a 2GB I tried.

BIG QUESTION - STANDARDS - why can't the SC126 read the Linc80 CF cards. To my mind they have identical data on them and the same rules about "disk" sizes (8MB) so why can't they read/write each others disks. Surely what is written to the disk should be the same?

At least the SC126 can use a FAT partition to transfer many files at a time from my Windows machine to it.

Alexander | Oct. 13, 2020

Very Nice Kit

Very nice kit, build quality is very good. Documentation was very clear which for me not being an experienced builder was very helpful. Once I started the build it came together pretty quick Once complete I gave it a quick clean and powered it on came to life first try got into CP/M and have since spent months trying to find some software & manuals.

Overall a very nice kit, relatively easy to build and easy to use and well worth the money.

Richard | Sept. 29, 2020

An excellent kit

Well documented, complete and straightforward to assemble. Most importantly, it works well and it is suprisingly fast !

Jaittarius | Aug. 25, 2020

One of the best retrobrew computer kits!

I've built many Z80 based SBCs and this one is the best. System is extremely stable with great performance with tons of expansion options to choose from. Easy to assemble with good build quality and the color documentation is a nice touch. Had a ton of fun building this and may purchase another just for the fun of building it again. Highly recommended for retro SBC fans

Jim | Aug. 23, 2020

A great kit!

I had some health issues last year and botched the build of a project. I was looking for something to build some confidence (I've built a lot of radios and computers over the years and most have worked on the first try). This one did that--I skipped a lot of the checks suggested along the way and wondered if I'd regret it later. But the instructions were good, no errata tucked away for you to discover later, and plenty of pictures. Still figuring out the nuances of RomWBW, but love the system. Ordered two serial ports because xmodem transfers never work with just one--except they do on this one! I figured I'd give it a try before firing up the second serial port and it worked flawlessly. Transferred my favorite assembler over and tested the Z180 logic in my CPU identifier for the first time. (It worked.) Wrote a BASIC program to tinker with the onboard LEDs. A nice kit that I'll be recommending.

Piero Giorgio | Aug. 12, 2020

Retro computing at its best

Very nice, very expandable retro computing system... You can relive the glorious initial days of computing, or even just get things done. And make use of a vast software base from the CP/M times.

Christopher | Aug. 2, 2020

Excellent board!

This is a fantastic kit! Shipping was faster than expected coming to the U.S. I had this assembled and up and running in just a few hours. Worked on the first try, no troubleshooting or tracing. I love the built-in dual ROM, dual serial ports, SPI, and I2C. I like the modular backplane too. Good work!

Eric | July 28, 2020

Excellent SBC

I bought this kit and even with overseas shipping received it quickly.

It went together in one evening and worked on the first go. The instructions were very clear and the assembly was easy. I am very pleased with the SC126. It's a great platform for RomWBW and is expandable.

I was so pleased I've ordered more items from this seller.

Tadas | July 16, 2020

well thought out kit

* Rock solid stable
* Loaded with lots of goodies in the ROM from the beginning
* Great docs
* Really detailed and well done silkscreen

Overall awesome kit!

Kurt | July 11, 2020

SC126

Very good product.
Very fast delivery.
Documentation and support very good.
I would buy again.
Kurt

Mogens | July 3, 2020

SC126 - Highly recommended and very capable system

This is an excellent kit to build your own Z180 microcomputer. It is a fantastic retro-experience and you end up with a fully functional system, very capable of running real (retro-)applications.

I initially built the smaller and also excellent SC114 kit, since I had no experience at all with soldering and building electronics (I am a software engineer...). I love the simplicity of the SC114, and it was a great opportunity to learn about building digital computer electronics. It made me confident that I could build the SC126 as well.

Documentation and assembly guide is very clear; take the time to read through everything before soldering, and don’t rush it if (like me) you only have little experience with electronics. But don’t be scared :) it is not too difficult - my kit worked on first startup. Do the quick tests as described during assembly, and you will know you are on track.

Included ROMs offer a lot of software to explore out of the box, and the SD card adapter is a great “mass storage solution” for additional software and data.
I recommend downloading and installing the “hd_combo.img” from ROMWBW to an SD card, and try the ZPM3 system, which is a capable OS compatible with CP/M.

I have set up a Raspberry Pi as “frontend” running the minicom terminal emulator, with SSH access. In this way, I can access my SC126 from anywhere 24/7.

I highly recommend the SC126 kit, which is a very high quality, professional product at an attractive price.

Yoshiaki | June 27, 2020

The best RC2014 all in one kit!

I bought this kit in November last year as my first RC2014.
Since then, I enhanced CF memory board, SC129 Digital I/O Module, Dr scott's Bus monitor, Single stepper, YM2149 sound card, and J.B.Lang's TMS9918 video card,etc.
This genius Z180 board is equipped with 512k/512k paging memory and RTC for RomWBW, therefore no need to add function with other boards basically.
Maybe you might have to buy bus extension board for future enhancement fun.
Thank you Steve, you introduced me to awesome RC2014 world.
And I'm very glad to hear this SC126 selling over +500 kits !
Congratulations and thank you for your kind support !
Anyway, this is very good kit for newcomer to start RC2014 all in one kit and very affordable price.

Dominic | June 23, 2020

Exceeds expectations, this is an excellent project.

Price was excellent, delivery across the pond was swift. This was a well packaged and well presented project. You can begin assembly as soon as you open the box. I had a question about file transfer I put the the seller that was immediately replied to. thanks!

The PCB is labeled on both sides, assembly will take 2 plus hours there is mercifully no surface mount soldering so anyone with a decent soldering iron and moderate experience can put this together. Don't rush, take your time and give the instructions a once over before diving in. The high definition photo online and the excellent silkscreen text on the PCB are very helpful. Once assembled and connected serially (I recommend using ExtrapuTTy because it has built in xmodem file transfer) the ROM based CP/M has xm.com to initiate xmodem file transfer with your host. Loading up your CP/M games is easy once you get started. Controlling the output to the LED readout on the board is a simple command in mbasic or assembler so let your first program be some kind of blinky lights to celebrate a job well done.

One more thing my other z80 projects ran at 2 to 4 mhz, this board is much faster and the 115200 baud rate is also much faster than what I was used to. Very responsive

other nice things: Battery backed RTC, all glue logic done with TTL, SD card "hard drive" all indicators of a well engineered project.

Highly recommended to anyone even slightly interested in retro computing, you wont regret this purchase.

John | June 13, 2020

Something to Aspire To

As a fellow hardware designer in the Z80 retrocomputing community, I can say that Steve's kits are something to aspire to. I recently bought his SC126 Z180 motherboard, SC112 backplane, and SC113 backplane expander, and all are of the highest quality and an incredible value for the money. The amount of effort he puts into both the design of his boards and the documentation for them is outstanding. Having designed a few boards of my own, I know how much work this is. He's very responsive to questions or feedback on the RC2014-Z80 or retro-comp forums. He has been an excellent contributor to the community for his own products and beyond. Highly recommended--I would not hesitate to buy any of his products again.

Ed | May 29, 2020

Five-star kit, would buy again.

This is a very nice kit, superbly packaged and with comprehensive documentation in the box and on www.scc.me.uk. Shipping to Switzerland took just a week even with the current delays.

Construction was straightforward; a few of the ground plane connections took a while to warm up and I had to go over those again (a couple of LED cathodes, and the battery holder) after running through the checklist in the assembly instructions. Once those were fixed it was ready to go and since then I've been playing Zork on it non-stop.

The next time I build one I'd fit the resistor network RP1 before the IC sockets; it was a bit fiddly dropping it in the holes with the obstacles in the way on either side. I had to double-check the pictures before plugging in the SD card adapter because both slots are labelled "SPI SD Card 2".

It's very convenient to be able to power the board from the plug-in USB serial adapter; it keeps the space on my desk much tidier than it would be with a separate power cable, and having to find somewhere to plug in another supply.

Radek | May 19, 2020

I'm very satisfied with this product.

The SC126 has very good documentation at it was easy to assembly it.
It is good product with excellent balance between functionality and complexity.

Simon | May 15, 2020

Very professional kit

I bought this kit a few weeks ago to play around with the Z180: it's nice to be able to program the microprocessor directly and not have layers of operating system in the way!
This is a very professionally produced kit and the instructions are both clear and comprehensive. The guide to building the kit as well as simple testing and trouble shooting are excellent.
I have subsequently bought a number of other kits form Steve and they are all excellent quality with great documentation as well as being very good value.
I would also add that even with the delays due to the virus, all the kits arrived very quickly and very well packed.
I cannot recommend these kits highly enough.

Catalin | May 5, 2020

Excellent product

From our very first interactions Steve went above and beyond to ensure customer satisfaction. It's very clear he's very passionate and loves these products.

The board and all associated components were received a couple days later, very well packaged. Every little detail has been well thought out and shows the love for the product and respect for the customers.

Included in the package is a A4 page with the kit contents. Taking the components from the shipping bags and placing them in the proper spots on this page took about 30 minutes, including measuring the resistors with a multimeter to double check the matched color codes to values.

Next step was to visit the assembly instructions web page on Steve's site (also printed on the above mentioned A4 paper) to get a general idea of the assembly process. Everything is straightforward, and all components are clearly printed on the board itself. If you have basic experience you don't even need to refer back to the web page while soldering the entire board.

Soldering took about a day. Sure, it could've been done in 2 - 3 hours, but why rush? Better savor the experience, like a good box of fine chocolates. Then, as told on the assembly instructions, followed up with thorough visual inspection of the solder joints and multimeter checks for shorts in various key places on the board. I confess I skipped on the voltage checks, but can you blame me? By that point I was getting impatient to get the whole thing running and trusted Steve had already checked the components for correct functioning.

Placed in the ICs and oscillator, hooked up the serial to Usb converter and the SD card adapter, triple checked that all jumpers were in the right positions according to the user guide and proceeded to connect it all to the computer. The 8 on board leds proceeded to light up one after the other as the system was starting up. Then, much to my surprise, all of them stayed lit...

This caused a bit of confusion. According to the assembly instructions the leds should've all turned off at some point. A quick check on the common errors page cleared the confusion. See, the system comes with 2 Flash chips. Apparently the led behavior described in the assembly instructions is for the Small Computer Monitor (SCM). But if the jumpers are placed in the positions shown in the assembly instructions RomWBW is used on power up and not SCM. And with RomWBW the leds all stay lit until a boot device is selected thru the terminal. Phew!

On Windows 10 the drivers for the serial to USB converter board included in my package weren't automatically installed, but were easy to install manually. After installing Tera Term I was able to see the boot messages from the board and then fun began. There's a lot packed in the RomWBW Flash chip, from CP/M to Z-System and even a small game so you can hit the ground running and already have a lot of stuff to play with immediately after assembly.

To sum up, apart from the small confusion with the leds which perhaps can be cleared in future by minor edits to the assembly instructions the entire build process was extremely fun and smooth and the system ran on first power on. Looking forward to playing with it further and expanding it's possibilities over time with more hardware and software.

If you're a computer enthusiast looking to build your own 8 bit computer you can't go wrong buying this product. Highly recommended!

Response from Stephen C Cousins | May 6, 2020

Thanks for the feedback.
I've now included a short description in the assembly guide to clarify what the LEDs indicate at power-up for RomWBW. The description for the Small Computer Monitor remains as it depends on which position you fit the ROMs as to which will run with the default jumper settings.

Xander | May 3, 2020

So much fun to put together and play with!

I ordered this kit as my first step into the world of Retro Computing. It's a lot of fun to solder together. The instructions on the site are very clear, with a couple of steps long the way, where you check your work, make sure everything is still as it should be, before proceeding any further. The board worked right off the bat, once I had all the chips inserted, so that was a great experience. The creator is active on the Google group, and very helpful.
Now I just need to figure out all the amazing things I can do with it!

Gerald | May 2, 2020

Top Quality Product

The board and components supplied in this kit are very good quality. I'm doing some exploration of the 8-bit retro micro market and in doing so, discovered this kit.

It's a very straightforward assembly, well-documented and includes 'waypoint' testing, to ensure you haven't had any construction faux pas. As the Z180 is a superset version of the Z80, many retro fans are likely to be familiar with this architecture but as it also includes many of the most useful peripherals on the same chip, including a Memory Management Unit which extends the memory scope from 64Kbytes to 1Mbytes. Rom options are supplied so you can install the designer's own ROM (which has all the yesteryear features of a 'Monitor' similar to the NASCOM...) as well as a RomWBW that provides a ROM-based CP/M, Z OS, MBasic (similar to RC2014's Basic ROM), Tiny Basic, Forth.

If you're looking for something with expandability that's got a lot straight out of the starting blocks, I recommend this as a great choice.

Peter | April 29, 2020

Great single board computer

A Z180 based single board computer kit. The circuit boards were clean and of good quality, and a guide for assembly and debugging was available online.
The board was moderately easy to build and worked first time (after a little coaxing to get communication between it and a laptop). The result is a CP/M computer with standard software utilities and an adequate selection of development tools (editor, assembler, loader, debugger). This is an excellent product on which to learn the CP/M operating system (for old times sake) and assembly language programming. Next steps are to install a C compiler and to use the board to control a small home automation system.

Miodrag | April 25, 2020

Best kit ever

This one is best kit ever, by my opinion. It is complete system based on Z180 and have all capabilities you seen to enjoy world of CP/M. Stephen did a great job documenting assembly process (including all options) and it was really joy soldering kit and playing with it.

Alexander | April 12, 2020

Good z80 sbc!

Fair price especially for full kir, works flawless, very good extension capabilities.
Sent fast and well packed.
Like it a lot 👍 and recommend if you want to make fast / extensive and useable cpm sbc.

Gerd | March 22, 2020

Very good job!

Built as described ... well, something like that. Switched on - yes, I had to think about setting the jumpers and you should do that beforehand - but it works.
Hats off, because there is a lot of work in development, documentation and so on - and criticizing is quick. Very good job - what I can say about everything I bought here.
Gerd

Vincenzo | March 13, 2020

Top-quality kit at an unbeatable price

The SC126 is one of the best amateur retrobrew kits available today. You get the full monty pack: a very high-quality kit, excellent documentation and build instructions (available from the constructor's website), and a quite powerful and extensible Z180 machine, which can run CP/M and FUZIX. And all of that at a very reasonable price, compared with all the other RC2014-compatible kits. Stephen is a very kind person, and replies to emails promptly.

This is probably not a kit for total beginners at soldering, since there are a few hundreds through-hole pins to solder, but it's definitely a very good option as your second project.

George | March 4, 2020

A very excellent microcomputer

Everything was working perfect. The documentation was very detailed.
It reminds me my first single board microcomputer which was build around the SC/MP chip in 1980's
Thank you Steve!

Francis | Feb. 25, 2020

Wonderful kit, documentation and support

This kit quality level is the highest you can imagine from a hobbyst. Documentation for assembling is precise and exhaustive, and Stephen is always willing to help.

To put this respectable and powerful Z-80 derivative computer in a nice case, I replaced the power LED and button and the 8 status LEDs by header pins so I could have them on the front panel linked by simple Dupont wires. This is something you could decide before assembling if you want to avoid unsoldering them afterwards, especially the power button. On the other hand, this kit is so inexpensive that you could also consider buying another one!

Be sure to check the tests Stephen has put in his assembling instructions. There are no difficult solder points, but they are quite numberous so patience and calm will be your allies rather than excitation and speed, which will come when you first power the computer on.

This kit gives you a complete and powerful retro computer with a lot of possibilities and peripherals. Be sure to check Stephen site for his design tutorial series, and the LCD and I2C code examples that fit this computer perfectly and open perspectives.

The 2 sockets could be a limit for you, although the SC126 is already fitted with what is generally using 4 or 5 sockets on a classical RC2014 computer. Should you need more sockets, Stephen has a choice of backplane boards which can expand the SC126.

I choosed Spencer Owen's PiZero Terminal (look for this on Tindie)to have a keyboard and an HDMI screen, but this kit can talk to any computer terminal software right off the box.

Probably my best buy since I started to learn electronics 4 years ago.

Daria | Feb. 15, 2020

Wow! ... Fantastic product and great documentation!

I was not let down at all by this economical yet quality computer kit. It's very functional, easy to build and works a treat. Love the balance of features and the low cost! I ... love this little machine and it's got fantastic documentation behind it to not only help you assemble and troubleshoot, but to operate and expand. I would _highly_ recommend this computer kit for anyone interested in getting started in the retrobrew scene.

Thanks for making this and for giving us such a fantastic kit Steve!! <3

Cheers~

Timothy | Feb. 7, 2020

A well thought out, fun kit.

I bought this as hands-on introduction to Z80-ish programming, CP/M, and peripheral integration. It was also a way to play with Wordstar and other programs I dimly remember. With serial ports, I2C and SPI SD card interfaces pulled out to headers, I think the system has more than enough expansion slots to add other functions. I made Rotten Snow's "Storage Module using Compact Flash (for RC2014)" -- also available on Tindie -- for CF expansion and it works fine with this motherboard.

The board is a nice 2-layer PCB with white silk-screening for parts placement. I really like that the chip and component positions are also appear on the bottom silkscreen. The bottom print also includes the pin-outs for the RAM and flash chips as well as the assorted serial I/O headers. Those a nice touches. Assembly was straightforward and the kit included a number of straight and angled headers, leaving some build options available. The parts-count was spot-on and you'll end up with some spare headers.

Getting the board running was relatively pain-free. Setting the configuration jumpers caused the most concern and needed a number of passes through the manuals. That's just the trade-off between simplicity and flexibility. I think Stephen opted to leaving options open for users. The system is pretty well documented and it's easy to find the schematic, board layout, various manuals and software sources. There is also a user forum for this. I'm slowly working my way through the ROM options and monitors...

Nice job, Stephen!

Colin | Feb. 7, 2020

A quality and professionally produced kit.

This kit is extremely comprehensive in every detail, components, peripheral options, hardware and pcb all of excellent quality and complete.
The build instructions and other related documents are professionally written and very easy to follow giving a fully operational CP/M - z180 computer.
Coupled with the well supported ROMWBW firmware the result is a powerful combination.
This has been for me a very satisfying build project and enjoyable experience.

David | Jan. 24, 2020

A Great Design, Well Documented, and Simple to Build

First impressions mean a lot. What hit me first about this kit is how compact the design is: at overall dimension of 4" X 6.5" (101 mm X 165 mm), this system is quite compact. It took a couple of days on and off for me to build, but the documentation is clearly written (especially the assembly guide, troubleshooting guide, and user's guide), so making the checks necessary to ensure a successful build before power up are duck soup for anyone who knows how to use a multimeter.

The soldering is somewhat fine work, so having an iron with a finer tip and good heat transfer is imperative. With my aging eyes, use of a stand magnifier was very helpful, but someone with normal vision will find no challenges so long as they are familiar with good soldering and electronic construction techniques. One strong suggestion: READ and FOLLOW the assembly guide. This is the best path forward to a successful build.

There are provisions on the board for such niceties as a remote reset switch, and multiple paths for supplying system power (5 VDC at less than 0.1 a), obvious signs the designer anticipated people building these systems into cases. I definitely have plans for mine.

The included firmware makes this machine truly versatile, able to boot straight to BASIC, FORTH, Z-System, CP/M 2.2, the system Monitor, or from systems stored on any available bootable media (microSD card in my case).

CP/M is an 8-bit system that usually only has 64K of RAM available, and most CP/M systems back in the day ran around 2 to 6 MHZ, with the latter being rare. . This design, with its Z180 CPU, is capable of operating all day long from a USB battery pack (I'm using a 10,000 ma-hour pack presently) at 18.432 MHz, so very fast, and very powerful for an 8-bit system.

Be aware that a serial terminal is needed to communicate with this system. The optional serial adapters sold for the board are well worth having, and will make interfacing this system to serial terminal emulator software like minicom or TeraTerm a simple matter.

My kit took about two weeks to get to the Gulf Coast of the United States from the UK, probably because of heightened security associated with current events (U.S. Customs probably suspected it was a noo-kyoo-lur dee-vice...), but most folks get their kits a bit sooner. It was packed well, and arrived with all components in good condition, ready to go.

There is a strong but small community on the net supporting this system and doing interesting things with it. I hope to see you there!

Mark | Dec. 30, 2019

Great kit - a lot of fun!

The last time I built a kit was in my childhood (which was more than a few years ago) so I was a bit apprehensive. The instructions were remarkably clear. The circuit board very well laid out. The periodic tests instilled a lot of confidence. The best part? It arrived in the mail Friday evening, I sat down Saturday morning and by that evening I had a working cp/m machine right out of the 1980s! Everything worked exactly as advertised. Amazed that this cost as little as it does when compared to other z80 kits out there. Really an amazing value.

Wondering what others are doing for cases?

Craig | Dec. 16, 2019

I love it!

I had my kit built in a few hours; within an hour of it being up it was running fuzix.
Thanks to Stephen Cousins for the well designed and documented machine, and to Christopher David Farrar for the write up:
How to create an sd card for booting fuzix on an sc126

In linux do the following steps:

Drop the two image files into a directory or on the desktop.
I chose desktop.

Bring up a bash command prompt.

Change to directoy where you have placed following files:

- c126-0.3.ide
- s32m.z80

enter commands:

sudo dd if=sc126-0.3.ide skip=2 of=/dev/sdb conv=notrunc,fdatasync status=progress

sudo fdisk /dev/sdb

Once in fdisk do the following steps:

- list partitions with p command
- delete any partitions with d command
- create new partition with n command
- specify partition 1 - default
- specify 2048 starting block - default
- specify +64mb or let rest of sd card be used
- change partition type with t command
- specify partition 1 - default
- specify partition type 7e
- write changes to disk and exit with w command

if you create a 64mb partition above instead of using rest of card, you can add
other partitions like a fat16 or fat32. The fuzix should ignore them.

Once back in bash do the following:

enter command:

sudo dd if=fs32m.z80 of=/dev/sdb1 conv=notrunc,fdatasync status=progress

You are finished!!!!! :D

Greg | Dec. 13, 2019

Probably the best retro-kit available

I really like this kit. It is a very capable system on a single board. Less overall pins to solder than some other kits and has greater functionality. Other kits too closely follow the MITS 8800 paradigm: You get it together and you have no storage and limited I/O. The SC126 has mini SD Ram storage. Quality is very high, and the CPU provides integrated peripherals. If you are trying to decide which kit to assemble, look closely at this one.

Ramon | Dec. 2, 2019

The best kit i have.

Easy to solder (i am 50, and the "new" smd formats are dificult without magnifier, but this was really easy (1 hour and half aprox)

The board is really fast running Z80 code.

Now i want to port MPM to this board.

Hans | Nov. 23, 2019

This kit is too good!

It took me an afternoon to assemble this kit, download Turbo Pascal, WordStar and dBase II and run them like it was 1984! Highly recommended!

Michael | Nov. 22, 2019

Excellent board and great documentation

When I was a kid, I had a few home computers, but the one I remember the most was the Coleco Adam (with a Z80 processor). I stayed up late writing BASIC programs and even ventured into CP/M 2.2 and assembler at one point.

Fast forward to 2018, when I started following the retro computer scene. I watched ebay for some classic computers, but I wanted something that I could build myself. So I searched around for a kit based on the Z80. I eventually found Steve's Small Computer Central website which led me to his Tindie store. I bought myself the SC126 a few weeks ago. I chose it over the SC130 because it has Small Computer Monitor in addition to ROMWBW, even though it's a more complicated kit to assemble.

He shipped it the same day I ordered it and it arrived in the USA a week later. The kit was packaged well in a compact box with a great parts list with images of all of the parts on it and a link to the build instructions. After checking that I had all the parts, I printed out the instructions and started soldering. I must warn beginner and intermediate hobbyists, you should follow his testing procedures carefully. I thought I knew what I was doing and started poking a live 5v wire around the resistor on the power LED and managed to blow it. I should have read the instructions first.

Aside from the blown power indicator LED (which was completely my fault), the kit ran on the first power up.

I've already spent hours playing with the onboard LEDs and writing code in BASIC as well as C using the great z88dk and the newly minted SC130/SC126 capabilities it offers. I also ordered the SD card reader so that I can have "hard disk" storage with CP/M. I'm having a total blast with this kit.

I'm looking forward to ordering some PC boards from the various community designs that are out there for the bus and even designing my own at some point.

That leads me to documentation. Steve's documentation is incredible. I've not only been able to easily build this kit, but I've also learned a lot about how the board addressing and the Z80 processor works from his website.

The community around these boards is friendly and welcoming and they've got some amazing ideas. I'm probably going to buy the SC130 just because I want to build another kit. This one is a lot of fun.

Ross | Nov. 3, 2019

Great little kit, exceptional documentation.

A great little through-hole kit that can be put together on the kitchen table in a couple hours or less into a working 8-bit computer that has the same retro user feel (but smaller and faster) as the early 1980's homebrew and commercial machines. The online documentation is exceptional- user's guide, circuit description, detailed assembly instructions, ROMs- all of it right there.

Richard | Oct. 28, 2019

Amazing kit, a must buy for tinkerers!

Fantastic kit, and incredibly well documented. I found this to be a "medium" skill level assembly, but if you're patient and follow the instructions you will have no issues. Check out the documentation on the website first to ensure you are comfortable assembling. Great price, worked flawlessly, would definitely purchase from seller again!

Martin | Oct. 25, 2019

Very well put together kit for Z180

The documentation is excellent, it was very easy to put together correctly. Worked on first try. I highly recommend this kit for anyone wanting to get into Z80 type RC2014 echo system of retro computers. /Martin

Randy | Oct. 25, 2019

Great kit design with great instructions for a low price

This kit was mostly easy to assemble, even with the large number of solder points, but low parts count. Some of the ground-plane solder points took a lot of time to get hot enough for solder to flow, as they nearly fully surrounded with copper. Having two vertical expansion slots plus one horizontal backplane expansion slot is fantastic and I've had great success with multiple RC2014-style cards inserted. SD card adapter and serial adapter worked without any problems and I had a fully-functional serial CP/M system in very little time. The included parts sheet is very useful and the online assembly instructions were clear and organized well, and included testing instructions along the way to verify critical points (much appreciated). Shipping took a little long (from UK to US), and there wasn't an option for a tracking number that I saw, so it was a bit of a wait, but the box was well packed and arrived in great condition. I'm looking forward to more kits from this Maker. Fantastic value for the price!

Donald | Oct. 11, 2019

Fun new dev board

I'm enjoying using the new SC126 development board based on the Z180.
My only complaint is that the manual needs to be gone through with a fine-tooth comb so ppl know which jumper does what. Just because the SC130 has been released recently is NO excuse to not go back and clean things up. Thanks.

Response from Stephen C Cousins | Oct. 17, 2019

Thanks for the feedback.
Jumper settings are described in the SC126 User Guide. I just checked this document and it does describe the function of each of the jumpers. I did, however, find one mistake which I have now corrected.
I have also added a link to the user guide in the section of the assembly guide where it illustrates the initial jumper settings for testing the board. Hopefully, that will make it more obvious where to find further details.

Randall | Sept. 23, 2019

Just get one!

Really cool little Z180 System. The Assembly guide is full of detail making it a very simple systems to build. Even if you soldering skills are less than perfect or your knowledge of electronics limited, I can recommend this kit.

All the documentation on Stephens web site is amazing, everything from the schematic to the firmware and software is easily acessible. References to the source for the software and for the firmware is included and makes tweaking up your SC126 very easy.

It took me roughly 3 and a half hours to build and get it running and once it was up it took little effort to flash the latest software to the flash ROM. And the old floppy drive and RC2014 floppy controller I have, worked perfectly almost out of the box, so to speak.

Great project, awesome kit and a joy to play with.

Thanks Stephen.

Wesley | Sept. 12, 2019

What a great computer

I've bought and built a lot of RC2014 stuff, and this board is just a standout. Good design, really well thought-out, and I have to appreciate how much it does with so few chips. I mean, there's a lot of chips on this board - but it essentially functions as 6 cards (CPU, Clock, RAM/ROM, Serial, Storage, RTC) in a regular RC2014 system, while still providing extra features. And only using 6 pieces of glue logic, and comes with a bunch of software ready-to-go, and did I mention it's *fast*?
Extra credit given for the documentation. Especially the provided inventory sheet, for organizing the components prior to installation. Other sellers take note!

Tuukka | Sept. 10, 2019

Great product at low price!

The kit arrived fast, and was very easy to assemble. A few hours after opening the package I was up and running the RomWBW CP/M - of course it depends on your soldering skills, but the board is easy to solder and silkscreened on both sides. I was prepared to flash the monitor roms myself, but even that was not necessary since the kit included ready to run flash chips!

Assembly instructions are very good - follow those and you just can't get it wrong. Some experimentation was needed in getting an SD card formatted and running CP/M, it was not crystal clear whether you should use the WBW or SCM monitor ROM. But carefully reading all documents resulted in success.

Even a one liner documentation comment on the ROM-drive CP/M programs would be useful. Some info can be found on RomWBW github page, and some by just running the programs. I installed an xmodem file transfer program, and only shortly after that noticed there was XM.COM already on the rom-drive.

Anyway, half the fun is finding out what you have. And with this kit, you have plenty to discover!

Response from Stephen C Cousins | Sept. 11, 2019

Thanks for the feedback. I've now added a note and a few links at the end of the assembly guide. There is information on my site about preparing an SD card etc. but I can see how you were left without guidance at the end of the assembly. Hopefully, the additional notes and links will help.

Jim | Sept. 5, 2019

A really nice project

This is a really well thought out and executed kit. It took just a week for it to arrive in the Southwestern United States from the U.K.

Upon opening the box, you'll find a great chart that has pictures of each part and the quantity you should have. My kit had NO missing parts. The assembly instructions are on the maker's website - and they are wonderful, step by step, clear directions. The on-board 8 LEDs were pretty, but functional - each ROM has a different startup pattern. Quite useful to know on first power up that you got it right.

Since the project contains two ROMs, the SCC Monitor and RomWBW, you can chose which to boot. RomWBW contains CP/M 2.2 and a Z-system variant so you can be up and running CP/M in no time. You'll need to source a small micro-SD card for storage, but this is pretty easy. I had a 64K card in the parts bin that worked just fine.

The board and parts are good quality. The board is silk screened on both sides to make it easy to locate and place parts. All in all, this was a pleasant project that went together quickly and worked the first time.

Chris | Sept. 5, 2019

This project was a pleasant one day build and worked first t

I loved building this project and it worked on first try. I also added a smbaker floppy controller to it which worked flawlessly after a re-configuration and rebuild of the romwbw software.

Karl Albert | Sept. 3, 2019

Power without the price.

If you are new to Z80/Z180 based soldering projects, this kit is not for you. The seller is offering another kit SC114 Z80 motherboard (https://www.tindie.com/products/tindiescx/sc114-z80-motherboard-kit-for-rc2014/) which is perfect for beginners. This kit is also very useful when building more modules as it will help with any troubleshooting.

The SC126 kit arrived quickly and came nicely packed in a card box, containing all the parts in neat plastic bags. With the package came also a poster showing all the included parts. Detailed assembly instructions and documentation of the kit is on the sellers home page. The system is relatively powerful compared to kits that cost far more. The heart of the system is the Z180 processor, which is basically a Z80 processor but with a lot of extra features like, a memory management unit (DMA), a counter-timer-clock (CTC) unit, and two serial ports. The system has also I2C and SPI ports, and a real-time clock. With a simple jumper, the system can run two bootloaders, the ROMWBW and SC-monitor, giving access to CP/M. Another nice feature is that is can be used to write to flash memory. And with the expandability, it is all in all a very capable system. Assembling this kit can be a challenge for beginners, but the instructions are very good and contain also troubleshooting guide.

Highly Recommended.

Michael | Aug. 30, 2019

Brilliant value SBC kit.

Good thoughtful design, well documented with instructions for testing at several stages of the assembly. High quality PCB, all components provided. Recommended for all but the absolute beginner (who might find the SC114 a good first project). Great price!

John | Aug. 27, 2019

Very Good!

I found this SC126 ver 1.0 to be a first class kit very easy to assemble and worked fist time! And the software supplied also very good!
My interest is purely nostalgic! Way back when, a local company had a problem the were paying £35.00 for a IBM formatted 8 inch disk, to solve there problem I purchased an old S100 computer with 2 X 8 inch drives and a VT100 terminal with CPM 2.2 ( lost the makers name!), I sold the formatted disks for £15.00, soon paid for the computer!
The S100 had disc’s for CPM 2.2, Wordstar, Supper Calc and others, this was my start on CPM, I found it fast and very useful, once I got used to the keyboard short cuts!
I purchased a Ampro Littel Board Z80 CPM 2.2 small PCB fits on a 5.25 inch floppy drive, very good PCB one of the best things was the ability to read lots of 5.25 inch formats.
Some years later moved to IBM PC.
I now would like to experience CPM 2.2 once more.
John Worden

Leif | Aug. 26, 2019

Great product but not for the beginner in soldering

Had been looking for a Z180 based product quite some time and was considering the RC2014 with an addon board. But then this showed up and with brexit coming it was best to act quickly.

Delivery was quick. 8 days from UK to SE of which I suspect the most was here in Sweden. It was posted the same day as ordered.

Took good time to read all the instructions available on the homepage before doing any soldering. Good instructions even if I choose to do things in a slightly different order. The only thing I miss is a bit more information on the included software. But it could be just that I have not looked close enough. There is plenty of information on ROMWBW, CP/M and ZSDOS on the internet. You just need to filter to find what's relevant and what's not for exactly this product.

The kit is complete down to the last little resistor and even includes some rubber feet. PCB was of high quality as far as I could tell. But one thing that might make this unsuitable for beginners in soldering is the thermal reliefs for pins connected to the ground plane. Some of these gave me a real problem and I consider myself as experienced.

Now, if there only was a matching graphics card to mount piggyback to this board....

Response from Stephen C Cousins | Sept. 11, 2019

Thanks for the feedback.
I think you are correct, there needs to be more information about the included software. There is quite a bit on my website, especially about the Small Computer Monitor, but I need to add more to better explain the rest. I also note the point about how this documentation needs to relate to specific products.
The issue of thermal reliefs is an interesting one, thanks. I'll try to improve this on any updates to SC126 and on future designs.