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Forum Index : Microcontroller and PC projects : Growing a Maximite
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James_From_Canb Senior Member  Joined: 19/06/2011 Location: AustraliaPosts: 265 |
Just to drag the thread back off track again, I remember the first Jaycar store opening in Haymarket in Sydney. They specialised in parts and kits, and were a similar concept to the Dick Smith stores. I was chatting to a sales person there one day and he told me about a Navy bloke who had gone to their shop to get help because his audio compressor/expander kit wasn't working. The reason? He hadn't used solder, he'd used epoxy glue. MOBI - was that one of your early ones? 
I remember that kit well because I'd built it with a large capacitor the wrong way around because that was what the kit instructions said to do. Aaah. The good old days. James My mind is aglow with whirling, transient nodes of thought careening through a cosmic vapor of invention. Hedley Lamarr, Blazing Saddles (1974) |
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| MOBI Guru  Joined: 02/12/2012 Location: AustraliaPosts: 819 |
Nope, wasn't one of mine - by the time Jaycar started, I was strictly (well, almost) digital. Besides I try to stay away from Poxy stuff - for good resin. Sorry about the horrible pun. 
I live in a country town (Millicent SA) with a population of around 5000 - an auto parts business in town started up as a Jaycar agency about 2 or 3 years ago. I tried to drum up business but could get not one nibble - the agency lasted about 12 months and left as quickly as it started. David M. |
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| MOBI Guru Joined: 02/12/2012 Location: AustraliaPosts: 819 |
I mentioned that I was doing a bit of fibreglassing - making windmill caps. Here's a couple of snaps - setting on the male mould and off the mould ready for a couple of coats of yellow flocoat resin. What has that got to do with maximites? In the background is one of my tray top campers and I intend to fit a maximite car and camper monitoring and control system. Loose connection, but a connection anyway. 
David M. |
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| memberx Newbie  Joined: 20/04/2012 Location: AustraliaPosts: 24 |
Gday guys, Have been long time reader and lurker on the forum. It is great to see some of the old timers and reminiscing about the good old days and BASIC programming. 6502 VS Z80, Just a few points that I am aware of. 6502 was introduced earlier than Z80. WOZ had already designed Apple 1 based on 6502 before Z80 was released. Z80 was much more expensive when released. Commodore had bought MOS Technologies makers of 6502, rest is history. Don't compare 6502 and Z80 on clock frequency. Both operate differently internally where 6502 has advantage of about 2.2 to 1. This mainly impacted on cost or RAM in early days. 6502 had a smaller instruction set but very powerful index addressing and zero page mode. Z80 had lot more instructions and ability to use register pairs in 16 bit mode, but most people don't realize that Z80 only had 4bit ALU (Arithmetic logic unit). 6502 had good support from dedicated peripheral chips 6520, 6522, 6532. Atari even developed number of their own custom peripheral chips "Pokey", "Antic", "CTIA", "GTIA" to support their 6502 "B" CPU in 400/800 computers. Atari were inovators in graphics area back in those days particularly "sprites". They had extremely polular 2600 game console based on smaller 6507 CPU and they were very big in arcade coin operated video game machines. In terms of overall performance there wasn't all that much between 6502 and Z80 back in early days. I had the privilege to work for Atari importer in Aus. back in late 70's when 400/800 computers were developed/introduced . Visiting Silicone Valley in those days was absolutely MAGIC. |
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| MOBI Guru Joined: 02/12/2012 Location: AustraliaPosts: 819 |
Welcome aboard. Your post was very eloquently put. Hope to see more of you on the Back Shed. David M. |
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9308 |
I second the motion, and thanks for the CPU information. I used to have a pottle with about 6 each of Atari's Antic, Pokey, CITA and GITA chips along with several dozen of the RAM chips - all gone now. I did not trash them, I sent them over the ocean to CircuitGizmo's territory.  The owner/operator of atarimax.com, as he restores the old machines. Antic was the GPU(graphics processor unit) from memory, or was that the CITA or GITA?  Pokey was definitely the sound processor.
The only chip he did not mention was FREDDIE. No, not Murcury. Freddie was the memory bank manager used in the 130XE computer, that had 128KB of RAM, but the same 6502 CPU. Seeing as the 6502 could not address more then 64KB of RAM, Freddie took care of connecting the 6502 to the required memory bank. Generally speaking, from what I remember(I never owned a 130XE), the extra RAM in the 130XE was mostly configured as a RAMdrive. Smoke makes things work. When the smoke gets out, it stops! |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 3802 |
I understand IBM chose the 8088 for what became the IBM PC because Intel could deliver whereas Motorola could not deliver the 68000. The Z8000 was behind both in terms of development/production. Of course IBM "only" expected / hoped for a reasonably successful computer. No-one expected what happened! I worked for an English computer firm at the time and we could get 8086 chips (suited our needs better than 8088) but could not get more than promises from Motorola and Zilog. We liked the 8086 architecture least but reality was we needed actual chips. The Intel tech guys were REALLY good. Knew their stuff and when asked tough questions either also knew the answers or actually DID get answers. (Just trying for more thread hijack.) John |
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| MOBI Guru Joined: 02/12/2012 Location: AustraliaPosts: 819 |
That's all right, I'll try and keep it sort of on track. I do enjoy all the ot chat, it is both informative and nostalgic. I still haven't put together a 3.3v power supply - I was going to breadboard one, but I may as well do the right thing and make a module I can use with any permutation of the MM - not real professional to fit a bread board to each application.  David M. |
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| James_From_Canb Senior Member Joined: 19/06/2011 Location: AustraliaPosts: 265 |
If you don't mind waiting on the post from Hong Kong, you could get one of these for only $2.12 including postage! Link to eBay Then again, at that price you'd really have to question the quality of the components. James 
My mind is aglow with whirling, transient nodes of thought careening through a cosmic vapor of invention. Hedley Lamarr, Blazing Saddles (1974) |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9308 |
@ JohnS and others - "The CPU's an old 8088" - Runaway with Tom Selleck. And this was made in the 80's when the 8088 was actually cutting edge, but the movie was set in the not-too-distant future.
As for thread hijack - I have to offer some apologies here myself - I have posted plenty of sidetracking posts. This was not my intention, I am just in nostalgic mood these days, and that is MM's fault!!!!! Smoke makes things work. When the smoke gets out, it stops! |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9308 |
I recommend the Microchip MCP1703-33 regulator. Cheap as chips($1.15 each), 250mA output current, and uA of no-load current, dropout voltage of 0.6v. The 1703's have become my regulator of choice in practically all my designs these days. Available in a range of output voltages including 1v8, 3v3, 5v0 etc... MCP1703-33 Smoke makes things work. When the smoke gets out, it stops! |
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| MOBI Guru Joined: 02/12/2012 Location: AustraliaPosts: 819 |
Thanks for all the suggestions chaps. All appreciated. For my test unit I found a LM317 that Downwind had made up for a Nokia display experiment years ago and it is already set to 3.3v. I'll see how it goes and then see how I go with the MCP1703-33 etc. See, junk boxes DO come in handy some times. David M. |
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MicroBlocks Guru Joined: 12/05/2012 Location: ThailandPosts: 2209 |
Some have requested a schematic/pcb layout as i offered it. I have found some inconsistencies with naming pins. There are two naming systems used by microchip and others, and i mixed those two styles a few times. Let me fix that first, then i'll send it to you. Microblocks. Build with logic. |
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| MOBI Guru Joined: 02/12/2012 Location: AustraliaPosts: 819 |
Question on PIC32 internal regulator. The schematic shows on pin 85 (Vcap) a 10uF ceramic capacitor to 0 volts. Microchip data requires a low ESR cap (Cefc 1 ohm) at least 6v rating. Wondered what the Cefc stood for - is it electronic film capacitor? Must the capacitor be non-polarised? I don't have a great selection of capacitors and Jaycar is 400Km away. Is there any other cap that will work without beggaring the PIC? David M. |
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| paceman Guru Joined: 07/10/2011 Location: AustraliaPosts: 1329 |
I ordered one of those two weeks ago James - still hasn't arrived but I'm hopeful Mine was $2.69 though! When it gets here I'll load it up and do the same test I did for the other two small supplies a few months ago. It'll be worthwhile to add to that post (now that you've shown me how to do it!
Its specs are: Input: 6.5 to 12v, or USB Output: 3.3 or 5.0V Max output current: 700mA Greg |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9308 |
It is my understanding, that you MUST use a ceramic with X5R dielectric material for the cap on the Vcap pin. This appears to be mission critical. Geoff has stated that he used a tantalum one on some units, but SOME of them would not fire-up when built. The ceramic cap always works, so I read. Element14 have plenty to choose from in SMD packages of various sizes. I prefer 1210 package as it is nice and big and very easy to solder, but Geoff used an 0805 cap in his colour MM, which is tiny, and harder then you think to solder it. 10uF Ceramic SMD caps at Element14(0805's and 1210 sizes)... I am about to do an order from Element14 for other parts I need for my stock, and am probably going to get some of these 10uF ceramic caps, as I was thinking about making my own MM clone, so would need some. I would be happy to send you five or ten if you want. I would probably be ordering 100 caps at least, so would have plenty to spare. These are the ones I would be getting: 10uF Ceramic, SMD 1206, 6.3v These are 1206 size, which is smaller then 1210, but bigger then 0805's which are too small for my big fingers and shakey soldering hand!!! Smoke makes things work. When the smoke gets out, it stops! |
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bigmik Guru Joined: 20/06/2011 Location: AustraliaPosts: 2914 |
Hi All, Just a stupid question, I know I could look through the 10 gazillion pages of the Pic32 manual but what is the 100pin PIC32 pin spacing on the footprint? Is it .5mm (as in the 64pin) or .4mm as I see carriers for both. Regards, Mick 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: 9308 |
0.5mm as I unsderstood it, on page 6 million and five, paragraph 729, sub-paragraph 492.9, note #56.
Joking aside, you can always find the package dimensions right at the end of the PDF, so CTRL + END to go right to the end of the PDF, then a few presses of PAGE-UP should get you there with the least pain... EDIT: Page 219 has the 100-pin diagrams and footprints. They make the 100-pin beast in a 12mm QFP with pin spacing of 0.4mm, and a 14mm QFP with 0.5mm pin spacing. Smoke makes things work. When the smoke gets out, it stops! |
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| MOBI Guru Joined: 02/12/2012 Location: AustraliaPosts: 819 |
If you haven't ordered yet, can you include 10 for me? It would be appreciated. I know it is double handling, but I'm not desperate. The PIC32s on the MM are 14mm 0.5 spacing according to my stereo magnifiers and steel rule. (a bit agricultural) David M. |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9308 |
Okey dokey. I will PM you when they arrive, so I can get your address details. Should only be a few days - Element14 are pretty fast on delivery. Smoke makes things work. When the smoke gets out, it stops! |
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