ZX Spectrum Hardware Description

[@AstAMoore]

Clickable timestamps for easier navigation: 0:35 CPU, ROM & ULA 4:00 Upper RAM 6:10 Lower RAM, ULA Access & Contention 12:16 Video Output 16:55 Keyboard Interface. Phantom Key Presses 20:40 Audio I/O 23:15 Power Supplies. Common Failures

[@hristijanl.3997]

not all heroes wear capes!

[@absf6502]

The best zx spectrum hardware description I have come over. Clearer than reading my hardware books on spectrum. keep up the good work.

[@vladabuba]

Fantastic video! This is a kind of video I was watching for years to watch, and I noticed it now only by chance. I have looked for this information on several hardware sites, bunch of books and off course WOS. But here is all information presented in detailed and easily understood manner - I was glued to screen while watching and learning! Thank you so much for creating this video!

[@zedexspectrum4266]

As With All Your Videos I Found this Very Informative And Presented In Such A Way That I Could Follow And Actually Understand Thanks For This.

[@347573]

Wow, this was a very detailed, clear and interesting description! Got some "pearls" I didn't know about (e.g. faulty memory chips, splitted bus, low memory slowness, etc, etc)... Thank you!

[@nikamota]

Just show's you doesn't it!! We knew nothing as kid's when using any of these computer's..it was just of the time and a wow to all of us...but the Spectrum made by Sinclair was a very complicated peice of kit..as.outlined in this video...going through revision after revision in order to make it better.... I for one,now apprieciate what these people did.The ZX Spectrum is responsible,in large part,for the gaming industry,if not across the world but was responsible for the growth of the gaming industry in the UK. ...And Tim Follin *may have just "sampled" his amazing "5-channel simulation" music on the Spectrum 48k...something I had suspected at the time,given that,playing music into the Spectrum''s "Ear" socket would be output to the Spectrum's "Beeper" speaker which sounded very similar to Tim Follin's work on Agent X and Chronos..etc.. Now I know that the Spectrum had an analogue to digital converter....this make's sense now. Having said that...I could be wrong :-)

[@reallyniceaudio]

Still a fantastic video! I have watched all your zx videos now.

[@zoxwolf2133]

This....was wow man. Just wow. Now i will watch this few more times to understand it better :) Interesting video. Cheers

[@Wobblybob2004]

And good time of day to you sir!

[@claudiurus7307]

Great video!!! Why they added resistors in series on the data buss between the z80 and the ULC? Is this because they want to limit the ammount of current the ULC draw from Z80?

[@gasparinizuzzurro6306]

When two devices take over the bus they can set each line to different logic values. For example, assuming Z80 D0 is low and the other device try to drive the same line to high, you have a bus conflict, In terms of electricity you connected two points, one at 5V to another to 0V. This is a short circuit, drawing a lot of current and feeding a lot of current on the 0V side, which can damage both devices. this condition make the logical level not defined and it is unable to identify which logic value is on this line. To solve this, in a more canonical (and better) way, an high impedance state is used, so the conflicting device is electrically disconnected from the bus (as an example z80 can disconnect itself when a bus request is issued), but in order to save money they decoupled both sides using resistors. In this way each side of the resistor can drive and see the logical level he want to assert

[@claudiurus7307]

@@gasparinizuzzurro6306 thank you for the detailed explanation.

[@drgusman]

Excellent info! I'm trying to understand how peripherals showed menus and modified memory through NMI, any book recommendation?

[@ValChronification]

WENT TOTALLY OVER MY HEAD

[@herrfriberger5]

+ValChronification You need to know basic electronics as well as some basic computer organisation in order to understand this.

[@Tenraiden]

Thanks but the diagrams and text are too tiny!

[@johneygd]

That phantom key presses effect could ruin your work if you want to write a letter because if you press CSF at the same time, it will register Z to be pressed, and yeah, you should indeed never ever pull off an expansion module while the system is on as it could cause shortsge o,o,o. No wonder some people did hate the spectrum because of these syndromes. But if you are becareful in what you’re doing, it should run fine i guess.

[@anndroid3712]

it was so much fun -)

[@allthegearnoidea6752]

Not sure I can like you videos. I was a VIC20 man. I was very bitter at the time the vic 20 was crap but had better sound if I remember correctly.

[@RabidRat88]

It would be interesting to see a compared examination of the hardware of the spectrum and the C64 side by side. Not that there is any doubt that the commodore is vastly superior, of course.. :) How Sinclair ever thought a rubber keypad was acceptable as a keyboard is beyond belief. Very poor choice not matter what the budget for the machine was. Almost as dumb as releasing a QL without a GUI even though the Mac had already come out.

[@speedsterh]

Clive Sinclair wanted to shove as many Spectrum into households as possible, so he had to cut the costs everywhere. I owned a Spectrum, my first computer, I thought night and day about programming but when I had the C64, it was a whole new world for me (but I didn't really program on the C64)