CB2 micro computer KIT - Page 1
Forum section: electronics / general

author: sv3ora
author_rank: Regular Contributor
timestamp: November 06, 2019, 08:41:51 pm
content: Hi!I present you my latest project, my CB2 micro computer KIT.It is a very cheap and very easy and quick to build microcomputer programmed in BASIC.Website of the KIT:http://cb2.qrp.grFeatures:Standalone, no need for a PC to program and display.16 foreground and background colors on TV SCART (PAL/NTSC), pseudographics and composite B/W. HDMI/VGA support with external adapters.Sound with envelope and volume adjustment.PS/2 keyboard (or USB with adapter), RS232, 2x serial TTL, LPT, 8x A/D inputs and I2C, all BASIC controlled.Tiny-BASIC with featured embedded editor, Chip8, SCHIP, 8080 and AVR-native binaries supported.8 programs storage in internal flash, cross programs calls, external flash and EEPROM options.Terminal program, color terminal, X-modem transfer, PC connectivity.Games, applications and libraries available. Automatic program execute option on boot.Easy to assemble, through hole components and cheap!And much much more to discover yourself...Just hook up your TV and a keyboard and you are ready to go!I hope you enjoy it, just as I do!There are a few KIT pieces left.Visithttp://cb2.qrp.grBest regardsKOS

author: sv3ora
author_rank: Regular Contributor
timestamp: November 08, 2019, 10:34:06 pm
content: Two of my prototypes running my screen saver programs and networked through their RS-232.A retro net cafe?

author: granzeier
author_rank: Regular Contributor
timestamp: November 09, 2019, 09:43:01 am
content: Nice.Many years ago, Byte had an article about using serial ports for networking ("Ultra-Low-Cost Network for Personal Computers" Byte, Oct 1981,https://archive.org/details/byte-magazine-1981-10, page 50.) This network used as little as two resistors and a diode and RS-232 connector for each port, but could be expanded to provide more speed and more nodes. This could easily give you the "net" part for your cafe.Also, many years ago, a co-worker (in my USAF computer repair shop) had an idea of using many identical video game machines, which were networked together. These machines would be tied to a server, and could download any game for play. The player could walk up to any machine and request any game, rather than waiting in line for the most popular arcade game machine. No more wasted money, or space, on games which lost their popularity. This could also allow for multi-player games ("Multimachine Games" Byte, Dec 1980,https://archive.org/details/byte-magazine-1980-12, page 24,) something never seen back in the early 1980s.I think that you are on to something. Can video arcades make a come back?

author: sv3ora
author_rank: Regular Contributor
timestamp: November 09, 2019, 11:27:42 am
content: Quote from: granzeier on November 09, 2019, 09:43:01 amOh man, what a wonderful article! Thank you so much for digging this out. I can't hold myself back not to try it and if it works, I will add it to the board. I am not sure which of the versions though. A limitation is the voltage levels. The RS-232 port on the CB2 micro uses +-5v or something similar. I think the ULCNET can be made to work with these voltage levels. Well these won't be pure RS-232 but they will be compatible (after all the CB2 micro can communicate to PCs through RS-232).What can I say, a great thanks!In Greece, arcades were dissapeared within a few days following a regulation. It was so weird, one day you had arcades, the next don't!

author: sv3ora
author_rank: Regular Contributor
timestamp: November 09, 2019, 01:59:51 pm
content: Regarding the networked games, I have already done that. I have written the protocol for a server-client communication.Both the server and the client are BASIC programs. The Server is your Game or it can be a BBS or any other service. The client is the Colterm program and it is designed to interact with the server in different ways. The user only has to write the server to do what he wants to do with the clients.All comms are serial.See here to find out how I did ithttp://cb2.qrp.gr/usermanual/#10_The_communication_program_Colterm

author: sv3ora
author_rank: Regular Contributor
timestamp: November 09, 2019, 03:51:58 pm
content: Quote from: granzeier on November 09, 2019, 09:43:01 amWell, I have just realized this: In the CB2 micro, if you just short the TX and RX lines of the RS232 together, you get the same result as that the article states, without any additional diodes or hardware!Transmitted data from each station loops back to this station but also sent to the other stations. I have tested it with just two stations and it works.It essentially requires two wires, the GND and the common bus, since the TX and RX are shorted.So effectively you receive the same results as that of the article without any diodes or even extra negative voltages in place!

author: granzeier
author_rank: Regular Contributor
timestamp: November 09, 2019, 09:53:01 pm
content: Very impressive - you really jumped on this one.The thing about the RS-232 +/- 12V voltages is that it allows for much greater distances - but you probably would not need that for an arcade-type environment.

author: sv3ora
author_rank: Regular Contributor
timestamp: November 09, 2019, 10:04:16 pm
content: Well in fact, you can do more configurations the way CB2 micros have their Jumpers around the serial port placed. Based on different jumper settings on each computer:You can loopback all computers (one transmits all the other listen)You can make one computer transmit to all, but listen only from one computer.You can make more than one computers transmit to all the rest but not between them, and listen from specific computers only.And some other configurations.What a great article it gave me good ideas!Thankfully no hardware changes are required on the CB2 micros, it's all there already

author: granzeier
author_rank: Regular Contributor
timestamp: November 10, 2019, 10:52:05 am
content: This is great. I'm looking forward to the write up. Also, I hope that my former co-worker runs across this, and gets some kind of enjoyment out of it.

author: sv3ora
author_rank: Regular Contributor
timestamp: November 17, 2019, 07:39:14 pm
content: Quote from: granzeier on November 10, 2019, 10:52:05 amSee here for a draft unfinished text on the networkinghttp://cb2.qrp.gr/extensions/#3_Local_Area_NetworkI have to test the different scenarios to finish it.

author: granzeier
author_rank: Regular Contributor
timestamp: November 18, 2019, 01:52:33 am
content: One question: with all of the TxD lines tied to only the TxD lines, how does a receiving computer read the data coming from the transmitting computer?In ULCNet, the Tx and Rx lines are (essentially) tied together so that the data from the transmitting computer will reach all of the other computer's (including its own - so that the sending computer can detect collisions) Rx lines.

author: granzeier
author_rank: Regular Contributor
timestamp: November 18, 2019, 01:59:36 am
content: Quote from: granzeier on November 18, 2019, 01:52:33 amNever mind; I see that you answered that in reply # 5 - I thought that I had seen that somewhere, but missed it when I looked again.

author: sv3ora
author_rank: Regular Contributor
timestamp: November 18, 2019, 09:14:37 am
content: Quote from: granzeier on November 18, 2019, 01:59:36 amNot #5 but #7.The computers where the TX lines are tied toghether, and the RX lines tied together, cannot talk to each other. The ones that have their TX and RX lines tied in a null-modem configuration to the others, can talk to them. If the TX and RX lines are shorted, all the computers can talk to each other, including their own (loopback). By combining these settings (apart from the loopback case) you can do different network configurations.For example you can have one computer to send to all the others, but to receive from them individually, meaning that the other computers can send to this computer but not send to each other.And other configurations that I am going to explain in the website.

author: sv3ora
author_rank: Regular Contributor
timestamp: November 30, 2019, 11:49:36 pm
content: Hi,I have made progress on the LAN networking for the CB2 micros. See herehttp://cb2.qrp.gr/extensions/index.html#3_Local_Area_NetworkNetworking works as designed!I am going to test the rest of the cases but it's really fun to see all the computers in the LAN to communicate to each other!Have fun

author: guenthert
author_rank: Frequent Contributor
timestamp: December 12, 2019, 05:09:39 pm
content: Quote from: sv3ora on November 09, 2019, 03:51:58 pmWut? In RS232 the outbound signals are never tri state. If you bind them all together there will be trouble.You don't want one peer's TX on high connected to another peer's TX on low.There was a time, when RS422 (one master, multiple slaves) or RS485 (multiple peers) would have been used for such (and might still in industrial settings).

author: sv3ora
author_rank: Regular Contributor
timestamp: December 13, 2019, 12:48:20 pm
content: Might be like you say. All I know is that it works perfectly on actual tests I am doing herehttp://cb2.qrp.gr/extensions/#3_Local_Area_Network

author: granzeier
author_rank: Regular Contributor
timestamp: December 16, 2019, 11:33:58 am
content: Congrats on the Hack-A-Day write up.https://hackaday.com/2019/12/12/catch-the-old-school-basic-bug-with-this-computer-kit/

author: sv3ora
author_rank: Regular Contributor
timestamp: January 05, 2020, 04:26:47 pm
content: Hi, I have just completed all the networking scenarios for the CB2 micro. In this last examplehttp://cb2.qrp.gr/extensions/#3.2.4_Connecting_three_CB2_micros_a_PCthree CB2 micros are connected together with a PC and a dial-up modem in the same network and sharing data. Enjoy!

author: sv3ora
author_rank: Regular Contributor
timestamp: April 26, 2020, 10:47:23 pm
content: Check out the new games people are writing on the CB2 microhttp://cb2.qrp.gr/programsEnjoy!

author: sv3ora
author_rank: Regular Contributor
timestamp: June 10, 2020, 08:10:37 am
content: New Reversi game released for the CB2 micro!http://cb2.qrp.gr/programs/index.html#2.3_ReversiEnjoy!

author: sv3ora
author_rank: Regular Contributor
timestamp: September 02, 2021, 07:56:25 pm
content: I thought I should do an update on this.microBBS V2 software (http://cb2.qrp.gr/programs/#4.4_microBBS2) has been written for the CB2 micro (http://cb2.qrp.gr)With this one, you can run your own BBS on the MCU!With love, for the retro fans.Enjoy!

author: sv3ora
author_rank: Regular Contributor
timestamp: October 20, 2021, 01:10:29 pm
content: Hi guysSee how you can use your CB2 micro as an ASCII terminal with printer only output, or both screen and printer.I wanted to create a TTY terminal with printer, just like the old teletype machines.You can also convert your parallel printer to a serial one with this solution.http://cb2.qrp.gr/extensions/#3.2.5_Connecting_CB2_micros_printersAnd the software written for this, depended on the solutionhttp://cb2.qrp.gr/programs/#4.6_AsciiTERMhttp://cb2.qrp.gr/programs/#4.5_printSRVEnjoy!