Best Use For A Timex/Sinclair 100 / Sinclair ZX-81

[MarkO]

 

Nice article. I made it into a .PDF file for you. It's easier to download and print this way too.

 

I was thinking the Same Thing.. You beat me to it!!!!

 

MarkO

[MarkO]

Actually, I'm pretty impressed with what it can do considering what it has under the hood compared to say a C64, Apple ][, or TRS-80 Color Computer. The big drawbacks being the keyboard, and the poorly written 8K ROM BASIC. Internally though, it's an impressive machine considering the number of chips under the hood. When home computers came about, they were a bit expensive. The first home computer, the TRS-80 "Model I" was an extremely well made machine, and sold incredibly well considering it's $600 price point, which was about 4 1/2 percent of the median household income at the time ($13, 572). It was like spending $2400 in today's dollar.

 

<< SNIP >>

 

I totally get why it was a popular machine for it's time, why it had a big following of folks who loved it, and why it's still a popular vintage unit. I just started the thread as a joke, I have no ill feelings towards folks who owed, or still own one. It was just posted in fun... kinda like this:

Here was my thinking at the time.. The Apple ][+, has a fairly nice keyboard, but no Lower Case, and Disk Drives ( which at the Time were Quite Fast ), and cost well over $1000.00 ( USD ). The Sinclair, barely has a keyboard, and no Lower Case, and only Tape Storage, but cost $100.00 ( USD or less ).

 

My Second Computer was an Apple ][e ( with Lower Case ), and Cost me $600.00 ( USD ) ( I was a Half Owner, so $1200.00 ( USD ) for a used Apple ][e, with 64K and One 140KB Floppy, and a Monitor /// )

 

I would have liked to control stuff with my Computer, and found an article that showed how to Interface to the Apple ][ Game I/O Port and Opto-Isolator ( AKA Optocoupler ) and a TRIAC ( A Bidirectional SCR ) to control 120VAC ( or possibly Higher Voltage ) devices... I even bought all the Parts, but never put them together.. I was worried about Blowing Up my $1200.00 Apple Computer..

 

Now, a $100.00 Computer, that was a much more reasonably priced device to potentially destroy.. Unfortunately, there was nothing a simply as the Game I/O Port on the Sinclair, so duplicating the Control Circuit on it would have been much more difficult, for an 18 year old.

 

A few months ago I found this on eBay, and recognized it was doing what the Article I read in the 1980s was doing with the Apple Game I/O Port, but it used an Apple Slot.. Something Like this could be very easily adapted for the ZX-81/TS-1000 or C64, or CoCo.

 

MarkO

[MarkO]

Also... The Sinclair ZX-81/Times-Sinclair 1000 is still very loved....

 

New Hardware includes Replacement Membrane Keyboards, RAM Expansion with SD Card Storage, and AY Sound Module from RWAP Software.

 

Please note I don't own RWAP Software, or even own any of their products, but I do need a couple Replacement Keyboards for my Sinclairs.

 

MarkO

[JamesD]

I think with the TS-1000 they gained at least a dozen haters for every fan they created.

[John_L]

Well I'm certainly not a hater, all machines from those days had their pluses and minuses. Honestly, they're all interesting to me. I occasionally will go through MESS and fire up every system in there and see what I can do with it. Some are foreign language, some have hex monitors instead of a BASIC interpreter (I'm lookin' at you Apple I !!) It's interesting what you find. I recall finding a Z80 based system that used Motorola's MC6847 VDG Chip, and it was weird, because it was a Z80 based machine but had that "CoCo" feel to it. So, having cut my teeth on the likes of the TRS-80 Model I/III and CoCo's 1,2 and 3, I have a strong affinity to those machines, so I can understand why any given person has the same affinity for any given system.

 

I actually know more about Sir Clive Sinclair than most... He was IMHO like both Steves (Job and Woz) all rolled up into one. He always seems to be ahead of the curve. I was most impressed with the flat CRT... who was making flatscreen TVs in 1984... SInclair was, so I have nothing but respect for the guy.

 

@MarkO, I totally get why you wouldn't want to do something as non-standard as hacking your Apple. I won't even jailbreak my iPhone... !!! Apple's always charged premium prices, but they've been able to do it because they put out a good product. I was lucky because I worked at a Radio Shack Computer Center back then, and pretty much had carte blanche to do pretty much whatever we wanted to the display model, and, if we would have trashed it (which, btw, we never actually did), we'd simply box it up and send it off to repair in Texas and pull another from stock. Luckily we never trashed one, about the only possibility would have been from jammin' carts into the machine with the cart* interrupt disabled so we could pirate the game

 

I actually got so good at it that at worst, it would lock up the machine or start executing the cartridge. Most of the time though the computer wouldn't even flinch. The trick was to push the cart in just until it hit the plastic, which was intentionally a bit too small for the thickness of the edge card connector so when it was inserted, the slot "gripped" it. I'd push it up to that point, make sure it was lined up perfectly parallel to the slot, then with one quick snap, push it into place, and done right, the computer wouldn't notice. There's always warnings about how you could kill the machine by doing it, but honestly, done right, the possibility of frying the CPU was quite low. Still, despite that, none of the CoCo's I ever owned endured that. We did that at work....lol.

Edited July 17, 2014 by John_L

[JamesD]

Well I'm certainly not a hater, all machines from those days had their pluses and minuses. Honestly, they're all interesting to me. I occasionally will go through MESS and fire up every system in there and see what I can do with it. Some are foreign language, some have hex monitors instead of a BASIC interpreter (I'm lookin' at you Apple I !!) It's interesting what you find. I recall finding a Z80 based system that used Motorola's MC6847 VDG Chip, and it was weird, because it was a Z80 based machine but had that "CoCo" feel to it. So, having cut my teeth on the likes of the TRS-80 Model I/III and CoCo's 1,2 and 3, I have a strong affinity to those machines, so I can understand why any given person has the same affinity for any given system.

...

The Laser/VZ series from VTech. Complete with Level II BASIC ROM... with commands disabled and NOPs to disable casette on/off control, patches for the 6847, some added commands and empty space filled with garbage to make it look like it's not an exact TRS-80 copy.

It benchmarks faster than a TRS-80 Model III with AHL's BASIC Benchmark even thought the Model III BASIC supports integers. Also faster than Apple II's and C64's BASICs.

 

[JamesD]

BTW, the higher res graphics being generated by Z80 machines is pretty cool.

[Tickled_Pink]

After an exhausting search, I've finally found a best case use scenario for this vintage computer...

 

 

So how did you fix the door wobble problem?

[John_L]

Actually just ran into the image while researching the unit.

[carlsson]

Unless I'm entirely off the bat, the EACA Colour Genie also is a Z80 machine with 6847 graphics and some TRS-80 compatibility. However it is not cross-compatible with the VTech Laser series, despite both having similar ancestry and so much in common.

[JamesD]

Unless I'm entirely off the bat, the EACA Colour Genie also is a Z80 machine with 6847 graphics and some TRS-80 compatibility. However it is not cross-compatible with the VTech Laser series, despite both having similar ancestry and so much in common.

I believe it uses the 6845 (like the CGA cards), not the 6847.

The BASIC does have it's origins with Microsoft BASIC but like most machines, programs couldn't go strait from one to the other without some conversion.

It uses 40 characters per line so it's not like the Model I or the VZ.

 

[ClausB]

The Sinclair was a very clever design and a victory for minimalism. I built my 81 from a kit in 1982 and then expanded the SRAM internally to 16K eventually. I wrote a 256*192 bitmap graphics driver that worked with SRAM but not with the external DRAM unit. Great fun.

[bkrownd]

BTW, the higher res graphics being generated by Z80 machines is pretty cool.

 

Makes me sad that my parents never got me any decent software for my TS-1500, so it was largely neglected. Writing tiny basic programs that didn't do much got old really quick.

[JamesD]

BTW, the higher res graphics being generated by Z80 machines is pretty cool.

...

I meant to say ZX-80 btw.

 

Makes me sad that my parents never got me any decent software for my TS-1500, so it was largely neglected. Writing tiny basic programs that didn't do much got old really quick.

I don't know how much of the Sinclair software even made it to the US.

Some of the better games might have had timing issues.

At least you had more RAM than the ZX-80/81 & TS-1000.

 

The hi-res trick is recent so that wouldn't have been available back in the day.

FWIW, people have done the same type of thing with the TRS-80 Model I graphics.

[bkrownd]

I don't know how much of the Sinclair software even made it to the US.

Some of the better games might have had timing issues.

At least you had more RAM than the ZX-80/81 & TS-1000.

 

The hi-res trick is recent so that wouldn't have been available back in the day.

FWIW, people have done the same type of thing with the TRS-80 Model I graphics.

 

I mail-ordered a couple programs advertised in Sync Magazine, but I had very little money. I'm sure anything available in the UK would have been available mail-order. I wish I still had those magazines... (edit - haha it's on the interwebs: https://archive.org/details/syncmagazine_1984_01

 

I had a "high-res" graphics program for the TS-1500 at the time, but they were clunky homebrew things that were too difficult for me (as a kid) to do anything with other than draw some simple high res vector lines and arcs/circles

 

The official red label Timex/Sinclair games I remember were really poor, often text based "graphics". There was a version of Scramble I wanted, but never got hold of. I think I had the flight simulator, a 3D maze game, and chess, none of which interested me. (all from the clearance bin)

Edited July 23, 2014 by bkrownd

[Chuck D. Head]

I am probably one of the few who regret not buying a TS-100 back in the day. I kept looking at them as they were getting discounted deeper and deeper. Finally, they were down to two of them left at my local drug store at $12.50, but instead I opted to spend $10 to buy two 2600 titles I had never seen before; Fire Fly and Starfox by Mythicon. I absolutely know I would have gotten way more fun out of the crappy little computer.

[bkrownd]

Browsing the linked magazine scan, the "high res" program I had did 256x174 - it was "SW Hi Res". On my little black-and-white TV it looked pretty good at the time. I also had the "Word Sinc II" word processor.

[John_L]

The hi-res trick is recent so that wouldn't have been available back in the day.

FWIW, people have done the same type of thing with the TRS-80 Model I graphics.

 

I'd really like to see that, I've never seen any modern "tricks" that can be done to increase the resolution of the model I, if you know of an example off hand, could you point it out so I could check it out?

[JamesD]

I'd really like to see that, I've never seen any modern "tricks" that can be done to increase the resolution of the model I, if you know of an example off hand, could you point it out so I could check it out?

The programmer just altered the display RAM every other line during refresh to double vertical resolution if I remember right. Maybe there was more to it than that though, it's been a while.

The hard part was timing the updates to the screen refresh.

He actually wrote a game that used that.

I can't find the web page at the moment.

[John_L]

The programmer just altered the display RAM every other line during refresh to double vertical resolution if I remember right. Maybe there was more to it than that though, it's been a while.

The hard part was timing the updates to the screen refresh.

He actually wrote a game that used that.

I can't find the web page at the moment.

 

If you run across it, let me know. Thanks James

[ClausB]

The hi-res trick is recent so that wouldn't have been available back in the day.

 

Not so. I and others did it in 1984. See Wilf Rigter's article: http://www.user.dccnet.com/wrigter/index_files/ZX%20Video%20Tutorial.htm

 

I wrote my 256x192 hires driver in isolation but tried to sell it to a few ZX81 game developers and failed. Trouble was it couldn't work with the stock 16K DRAM, so there was some extra hardware required.

[ClausB]

The ad:

 

My 16K SRAM:

 

My kit came with an issue of SYNTAX. In it was an article by my future friend Lance and a note saying he wished to start a Sinclair club in my area. I phoned him and met him and he showed me his ZX80. Later I showed him my Atari and we helped start the local Atari Club, CHAOS.

Edited July 26, 2014 by ClausB

[JamesD]

The ad:

sinclair.jpg

 

My 16K SRAM:

ZX81comp.jpg

 

My kit came with an issue of SYNTAX. In it was an article by my future friend Lance and a note saying he wished to start a Sinclair club in my area. I phoned him and met him and he showed me his ZX80. Later I showed him my Atari and we helped start the local Atari Club, CHAOS.

The TRS-80 is all software, I wasn't aware the newer ZX-80 games required a hardware mod. But then I probably didn't read all the details.

[Alcoholics Anonymous]

The TRS-80 is all software, I wasn't aware the newer ZX-80 games required a hardware mod. But then I probably didn't read all the details.

^^ zx81

 

Not all of them do. There is pseduo-hires and true-hires. Pseudo-hires does not require any modification but you also cannot have an arbitrary bitmap display since not all bit patterns were possible. True hires on the other hand does allow an arbitrary 256x192 display. However, with one of the methods, it's only possible if the expanded ram available from Timex or Sinclair is modified by the addition of a diode. In the zx81 (and zx80), the z80 is directly generating the display by 'executing' the bitmap and this is not possible in the stock rampacks without the modification. Pseudo-hires was around in the day and led to some hi-res games, 64-column word processors and was used in at least one CP/M port.

 

I'm not sure why previous posts are discounting the basic as I found it to be preferable to eg, the dialect Commodore was supplying for its C64, minus the disk capability. It was slow, contributed by two factors -- written to be compact and more than half of the z80 time was spent executing the display -- but I thought it was a really good basis for learning. My 10-year-old self, in particular, was very driven to learn by the keywords printed on the keyboard itself. A lot of trial and error and finding out what those commands did drove the discovery. The keyboard itself was impossible to touch type on, so the keyword entry was a requirement, and I doubt had anything to do with saving a few bytes in a tokenizer. That allowed you to enter programs at a rapid pace, perhaps faster than an average person typing out full keywords on a professional keyboard.

 

There was a great spirit around that machine and it's the reason it has such a following today. It suited the audience it was intended for really well, but as it came down in price it found a new set of buyers among regular people for whom such a machine was useless. But with those new buyers found, the price war began and so did the home computer revolution.

[JamesD]

Preferable to the C64? You do realize that is Microsoft BASIC.