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Forum Index : Microcontroller and PC projects : Growing a Maximite
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CircuitGizmos Guru  Joined: 08/09/2011 Location: United StatesPosts: 1421 |
Z80 was my baby. What I "grew up" on. C9 Oh, and being a Yank, I got to call it a Zee eighty, just like everyone at Zilog did... Micromites and Maximites! - Beginning Maximite |
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9083 |
@ bigmik - Cheers for that info. Was not sure at all what the TRS80 had. @ CircuitGizmos - 6502 was my "Baby".  Although, to be fair, when I had learned all I could in Atari BASIC, I was just starting to learn machine code for the 6502 when I became more interested in PC's and their bits and pieces, so the 8-bit machines were dropped at that time.  EDIT: Oh yeah - the Zee 80. We always called it Zed 80.
Such is life - you move on to the next thing. I seem to recall that the Atari's 6502 was clocked at 1.8MHz, so just SLIGHTLY faster then the TRS80. I have no idea if the Commodore 64 was clocked at the same 1.8MHz, but it PROBABLY was, as the CPU was the same device, and there would be inherent maximum speed rules for the device, no matter where it was used.
Smoke makes things work. When the smoke gets out, it stops! |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 3678 |
Z80 had more powerful instruction set, though. That should get comments LOL John |
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BobD Guru Joined: 07/12/2011 Location: AustraliaPosts: 935 |
I cut my teeth on a Microbee which was a Z80. I used to be able to do the assemblies myself. I got so I could do mental arithmetic (for the JUMPs) in hexadecimal. Some say it has affected me to this day. The Z80 eventually came out in a 6MHZ version. That was a screamer. As for the instruction set, I can recall block moves up and down and the need for care if the source and destination address ranges overlapped. I even taught the Z80 at a Melbourne TAFE for a while but I still can't recall much more about the instruction set. I am struggling to even remember the register names. I can recall the HL reg. |
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| CircuitGizmos Guru Joined: 08/09/2011 Location: United StatesPosts: 1421 |
There has never been a better processor and never will be. Ever. Ever!!!1!  Micromites and Maximites! - Beginning Maximite |
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djuqa Guru Joined: 23/11/2011 Location: AustraliaPosts: 447 |
I love the smell of Z80 Assembler in the morning. The best feature of the z80 was the 2 banks of Registers which could be swapped easily. It was a brilliant concept. The feature that assisted system design was the DRAM refresh capabilities which meant simple designs like the ZX80 / ZX81 could be made with a small chip count. TRS80 / Microbee / Exidy Sorcerer / ZX81 and a swag of no-name clones all featured the excellent Zilog Z80 (2mhz) & z80a (4Mhz initially, later even faster) which was second sourced by lots of other makers. The Soviet Russians even copied it. Being also compatible with the early Intel 8080a processor provided a large selection of software could be ported including CPM80 O/S Comment about the 6502 An 6502 Clocked at 1.8MHz would be crushed by a Z80 at 1.77Mhz The TRS80 Rules. Still actually available in various forms, 6502/6800/6809 have disappeared ages ago. Plus the Zilog eZ80 is a new improved version that is clocked at 50mhz. VK4MU MicroController Units |
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| MOBI Guru Joined: 02/12/2012 Location: AustraliaPosts: 819 |
Well, it had more instructions anyway. What I liked about the 6502 was like the PIC, it had fewer instructions, but the big plus was the post and pre indexing addressing modes. I still have my Rodnay Zaks for the Z80 and Lance Leventhall for the 6502. I also still have a few Z80 MPUs and PIOs etc as well as a stack of 6502s and PIAs, ACIAs etc. Even a few sticks of 8k dynamic RAM chips + UVROMs. Nostalgia. From memory, the TRS80 used the 8080 but I can't be too sure. Somewhere around I still have the Trash80 manual but not the Trash80. The 6502 worked quite happily @ 2MHz and was infinitely faster than the 8080 running at 4+MHz. On the subject of etching the PIC32 board: the track width I usually use to go between DIL pins is what I used for the PIC32 footprint. I have only ever used the Kinsten coated (UV exposed) PCB and have never had a faulty trace, so I gave it a go with apparent success. I'll know for sure when I try to programme things. I've never used the toner transfer technique as I have a Brother. It was free, so I can't complain. It works wonderfully with the precoated Kinsten UV boards. When I came to fit the PIC32, I found I had a little too much tin/solder on the footprint and the chip didn't want to stay in place so I had to scrape the pads with a scalpel or the like. The next board I make, I'll dilute the tin paste more so that I get a coating rather than a raised track. Meanwhile, back to the "back shed" and make some more fibreglass hats for windmills - the paddock sheep and cattle watering type. I supply a couple of wind mill manufacturers. It is really a s...t of a job, but I can't find anyone stupid enough and competent enough to take it on. Any takers???? David M. |
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bigmik Guru Joined: 20/06/2011 Location: AustraliaPosts: 2870 |
Yeah a funny thing about that... Old man Don and I were watching a show called `beyond 2000' or something like that (circa the 1990's) and the chap was talking about a product that used this powerful processor called a C-80 and Don and I had no idea what a C-80 was.. (no real internet and google in this days)... Anyway it wasnt until some months/years later that Don received an audio tape from a Canadian friend that we listened too and we nearly fell off our seats when he spoke about a Zeee-80 (we always said Zed-80) then the penny dropped and we realised that the powerful processor from the `beyond 2000' show was actually the Z-80 that Don and I knew and loved. Regards, Mick EDIT*** It was probably mid 80's that we saw that show... Mik Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<< |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9083 |
If the Z80 was actually a better processor core, I wonder why they did not use it in the Atari's and C64's? Does anyone know? Sounds like the Z80 would have been a better choice in these machines back in the day. It has no relevance whatsoever these days, but it has made me wonder quite a bit, as I think the Z80 was a cheaper device too, was it not? Smoke makes things work. When the smoke gets out, it stops! |
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| djuqa Guru Joined: 23/11/2011 Location: AustraliaPosts: 447 |
Sorry mate your memory is failing you. TRS-80 Model 1, 2, 3 , 4 all featured the Zilog Z80 Don, BigMik and myself all had some of the first (if not the first) TRS80 Units made. When RadioShack first started making the units the z80 CPU cost more than the entire retail price of the TRS80, but RS knew it would drop once production ramped up. The woosy little 6502/6809e was only a Calculator chip on steroids and cost a FRACTION of the z80, but for the Apple][/atari/VIC-20/C64 usage (Cost sensitive designs dictated the choice of cpu) would never been used for much other than game machines (which a C64/atari is only anyway ) and process control. I have owned and used professionally all of those cpu's & the 6502/6809e is like a Mini, but the Z80 was more like a Ferrari. VK4MU MicroController Units |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9083 |
Wow! 
Very interesting stuff. So, with the Atari's and C64's or anything else with the 6502, was it the CPU of choice on cost alone? As it is the heart of the system, one would think that you would not want to pick the cheapest of the cheap here, as it directly affects how the machine performs. If the 6502 was chosen simply for cost above all else, it is even more amazing that the Atari's and C64's did so well in the day sales wise, if the processor at the center of the machine, was actually suffering from emphysema. Smoke makes things work. When the smoke gets out, it stops! |
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| MOBI Guru Joined: 02/12/2012 Location: AustraliaPosts: 819 |
Ok, I stand informed. As for one processor being better than the other, I think it is hard to pick as they both did things somewhat differently. The 6502 was a bare bones processor with powerful (IMO) addressing modes, whereas the Z80 (I taught them at Darwin Institute of Technology - now the UNI) was like an Aston Martin with satnav, blue tooth and voice recognition and any other feature you could fit it. Yes, I agree that it was/is a wonderful MPU - so much so, that Apple in their wisdom made a plugin board for the Z80 so that CPM80 software could be run. It was a little tricky as disk file operations etc had to be fed through the 6502 DOS. Still, it was my intro to Borland Turbo Pascal for which I am grateful. Didn't need line numbers!!! I still think, and mayber you don't agree, but if IBM had gone with Motorola or Zilog rather than Intel, we would be living in a totally different micro world today. David M. |
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| BobD Guru Joined: 07/12/2011 Location: AustraliaPosts: 935 |
I quite liked Borlands TP. You could do a lot with it. As far as IBM choosing Intel etc. you are probably right. However, history is full of these sorts of moments, choosing one path instead of another. |
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| bigmik Guru Joined: 20/06/2011 Location: AustraliaPosts: 2870 |
Sorry David, I actually had one of the first DICK SMITH System 80's. I did though add my DNA to many a TRS80 unit in Tandy stores by drooling over them before finally deciding (on price mainly) on the system80 (the same as the US clone PMC80). Oh!!! Who is Dick Smith?? He is an Aussie icon and now spends his time promoting his AUSTRALIAN made and produced brands of foods and profits go to charity... one of my heros... Here is his latest ad that was banned as too controversial... Disk Smith Regards, Mick Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<< |
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| djuqa Guru Joined: 23/11/2011 Location: AustraliaPosts: 447 |
System80 TRS80 were very similiar and ran the same z80 software most of the time. VK4MU MicroController Units |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9083 |
[quote]According to Free TV's Commercial Advice division, this ad is unsuitable for broadcast during the normal television viewing hours due to the high levels of innuendo.[/quote] Feckin' Hell. If they are gonna start censoring things because of innuendo now, what's the point of having TV at all? (rhetorical) I thought the ad was hilarious!  Smoke makes things work. When the smoke gets out, it stops! |
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| MOBI Guru Joined: 02/12/2012 Location: AustraliaPosts: 819 |
Looks like I started a mare's nest of memories here. We'll get that home grown maximite built yet. Any suggestions welcome. PS: did anyone ever use the 16 bit TMS9900 MPU with only one register (the work place pointer)? That was an interesting concept but was limited to the speed of the system RAM as that is where the "registers" were. David M. |
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| CircuitGizmos Guru Joined: 08/09/2011 Location: United StatesPosts: 1421 |
There was at one time - perhaps a very short time - a Dick Smith's Electronics in the U.S. I had a catalog. Might have ordered something from them. Micromites and Maximites! - Beginning Maximite |
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donmck Guru Joined: 09/06/2011 Location: AustraliaPosts: 1310 |
From Dr Google: (I remember well, when he went through this stage of development) Don... United States ============= In 1985 the first branch in the United States opened at 390 Convention Way, Redwood City, California. The location served as the main office, mail-order centre, kit-assembly area and retail store. Additional stores opened on Shattuck Avenue in Berkeley, California; Stevens Creek Boulevard, San Jose, California; and in Los Angeles. Within a few years the U.S. operation was sold. https://www.32v8.com/d |
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| paceman Guru Joined: 07/10/2011 Location: AustraliaPosts: 1329 |
I tried to develope a 6800 based data logging system for temperatures, speeds and lengths on a large casting station at the Bell Bay aluminium smelter in, I think 1978. The development boards were bought from Motorola. My Assembler skills were pretty much non-existant though so I programmed it using a Basic compiler. The compiler was loaded with an audio tape, several cycles of I think 100Hz tone for a 1 and of 200Hz tone for a zero - or something like that. The compiler had some handy features, callable Assembler routines, peek/poke etc, a single line of Basic could be printed back out in Assembler, de-bug per line of Basic or Assembler. The whole hardware thing quickly got pretty un-wieldy though with limited memory and I/O capabilities - every small addition needed a new board and they were expensive and big, about 250x160mm. I'd rather attempt that job with our capabilities nowadays than with the stuff available then. |
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