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Forum Index : Microcontroller and PC projects : Proto Board for the uMite 28
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Zonker Guru  Joined: 18/08/2012 Location: United StatesPosts: 761 |
Good afternoon all.. Just wanted to let folks know about a board I got spun up for the 28 pin uMite. I been having a good time playing around with the new chips and thought about small plug in board for it. After bumping into the CAD program for a week, I came up with board with an edge connector to support vertical mounting in a vector board or standard IDE connector, PICkit-3 connector, USB, and Rs-485... (just couldn't stop) Anyway, I wasn't sure if anyone else would be interested in this kind of thing. I could post the gerbers if anyone wants to try and order some. Might give the 44 pinner a try... I might have a go at getting some ordered to see if they work ok.. 2014-02-01_222639_MicroMite_PCB.pdf 2014-02-01_222753_MicroMite_Scat.pdf 2014-02-01_223338_MicroMite_Silk.pdf |
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9308 |
Very impressive. 
I see you have embedded a USB-Serial converter chip so that the unit can connect DIRECTLY to a PC without any external serial-port adaptor - very nice work. 
Perhaps Geoff does not need to develop his own board - he can use yours. 
I have developed a breakout board for the QFP, but just waiting for the boards to arrive from PCB Zone - they are very quick - usually only about 3 day average from me sending files, to my having my hands on the boards. Smoke makes things work. When the smoke gets out, it stops! |
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bigmik Guru Joined: 20/06/2011 Location: AustraliaPosts: 2914 |
Gday Zonker, If you are going to produce them and want to get a few orders to keep costs down I will be interested in a couple. Regards, Mick PS. Looks great. 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 |
Is it likely that you will produce a version of this PCB for the 44-pin QFP? Smoke makes things work. When the smoke gets out, it stops! |
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| JohnL Senior Member  Joined: 10/01/2014 Location: SeychellesPosts: 128 |
I would also be interested in dozen or more PCB's. |
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| viscomjim Guru Joined: 08/01/2014 Location: United StatesPosts: 925 |
count me in also! |
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MicroBlocks Guru Joined: 12/05/2012 Location: ThailandPosts: 2209 |
Looks good and compact. I do miss something though and that is a reset pin and a 3.3v on the connector. Would be great if you can squeeze those in. Is a standard IDE connector not 40 pins? Microblocks. Build with logic. |
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jman Guru Joined: 12/06/2011 Location: New ZealandPosts: 711 |
I would be keen on a few PCB's Jman |
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| Zonker Guru Joined: 18/08/2012 Location: United StatesPosts: 761 |
Wow... I had no idea there would be a response like this.. (sweet!)... Ok, well, let's first talk of possible changes... The way I was first thinking, the silly little 100ma regulator would just be local, but it could supply maybe 30-50ma outside if need be. They will shutdown on you if the fever gets to high... Also, there is no power protection here either. Hummm.... I guess we could bump up the "IDC" connector, (thanks TZ, I really need to learn how to type), to 26 pins and include a 3v out and extra ground pin. Now, if everyone wants to, we could go for a "bigger" power system, coming in with a "dongle" source, provide protection and supply both 3&5v sources to the outside. Doing this will cost the "way to small" holes area... The reset button will squeeze in somewhere... I would like to keep the Rs-485 transceiver as this makes an excellent way to string several of these boards together in a system. Lou Cassady and I have tested this subsystem during the uMite beta-2 part of testing and seems to be working like a champ... Anyway, let me know of any mistakes found and other ideas before we spin this baby up... And yes, I would like a try at doing a 44 pinner... I just don't see any "official" pin-out data yet, but Geoff is working his fingers to the bone over this stuff...!! I'm sure we here something soon... So far I'm seeing an order of maybe 30 (or so) boards.. we'll see... Thanks Gent's for the kind response.. 
Zonk PS:.. Just thinkin... We now have 28,44,64 and 100 pin versions of this fine "funwere"... Ausome..!! Thanks everyone, what a ride..!! |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9308 |
Personally, I don't really think that the little square of holes will be missed by many. That would also give you room for the reset button that TZA requested.
Smoke makes things work. When the smoke gets out, it stops! |
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atmega8 Guru Joined: 19/11/2013 Location: GermanyPosts: 722 |
Hi Zonker, put me on the list please. I am interested in 2 boards;-) D.S.
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| atmega8 Guru Joined: 19/11/2013 Location: GermanyPosts: 722 |
I prefer a small smd power led. Maybe multicolor, to show that both Vortages are ok? And a polarity protection? |
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| MicroBlocks Guru Joined: 12/05/2012 Location: ThailandPosts: 2209 |
LED's would be nice if they are connected through a jumper or solder pad. They are using a lot of current and will drain batteries. One remark about the FT234XD chip and that is you should be aware of its "Floor life", also called "Out of bag" or MSL rating. This chip is a MSL Level 3 which means it has to be 'baked' when exposed to ambient for more than 168 hours. 'Baking' is done by putting them in a oven ramp up the temperature to 125 degrees celsius and bake them for up to 17 hours. If this is not done then a 'popcorn' effect can occur, meaning that the moisture inside the chip will boil and change to steam fracturing the chip. This is often not noticable even under a microscope but it can damage the working and lifetime of the chip. It is one of the reasons why cheap USB-RS232 converter that use FTDI chips are unreliable. Microblocks. Build with logic. |
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| paceman Guru Joined: 07/10/2011 Location: AustraliaPosts: 1329 |
You live and learn Jean - I'd never heard of that issue. Greg |
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| Zonker Guru Joined: 18/08/2012 Location: United StatesPosts: 761 |
Good evening Gents.. Ok, First round of updates Done... Let me know what everyone is thinking on this... Zonk 2014-02-06_043829_MicroMite_PCB.pdf 2014-02-06_043912_MicroMite_Scat.pdf 2014-02-06_043946_MicroMite_Silk.pdf |
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BobD Guru Joined: 07/12/2011 Location: AustraliaPosts: 935 |
Back in the 1960s and 1970s I worked at IBM maintaining their mainframes and other. I also looked after a betting terminal they developed for the NSW TAB. It had unreliable electronics which was all commercial DIP chips. Some of the chips used to explode. I saw the results of this with a crater in the top surface of some of the chips. One day I had the covers off a machine and one of the chips blew. It was like a rifle shot and a piece of the chip flew past my ear. I left the company soon after and lost contact so I never did find out what was wrong but I wonder if it was moisture in the chips. I remember now that some of the chips had a problem with differential expansion (when heated) of the layers of plastic that formed the chip. That used to rip off the interconnects to the legs. |
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| paceman Guru Joined: 07/10/2011 Location: AustraliaPosts: 1329 |
Hi Zonk, I'm not at all sure I'm reading the diagrams properly but I see you've included the ICSP pins in the scat file but I can't see them in the layout. Also, what are thinking for a socket for the micro? Greg |
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| Zonker Guru Joined: 18/08/2012 Location: United StatesPosts: 761 |
Good morning Greg.. The ICSP connector is on the left side top of the board labeled PRG. I tried to layout this board using as many through hole parts as possible to make it easy for most people to build. I was thinking of installing the SMD parts first and sending boards out and letting users build them to the way they wanted. Some wanted the LED's, one lets you know if the AUX 5v is on, the other shows the MPU has power. But, you don't have to install them if you don't want to. Likewise, the board interface let's you install an "IDC" connector for using with ribbon cable, or you can use a 26 pin header connector soldered to the edge fingers to mount the board vertically for use with a vector board. I have a few 200 center to 300 center converters from the electric-freeks website that should do the trick for this. That way, it doesn't take up much space on a push-in type vector board, allowing easier to get to wiring area. Since the board can also be used as a programmer, you could use a nice "machine pin" wire wrap socket to elevate the socket to allow the installation of a good "Zif" socket if you wanted to. I just got a hold of the 44 pin data from Geoff, so I will be looking to spin up a board for that chip also. Unlike this board, the 44 pinner will be designed more like Geoff's 64 pin Mini-Maximite board, allowing the user to install it into a finished project. Let me know if this is not wanted by everyone... Oh my, it's after 7:00 here... Time to go to work... |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9308 |
Bah! Isn't it a pain how work gets in the way of us speding time on our hobbies? (rhetorical!)
EDIT: Oh, BTW - very sexy board now. Well done. Very efficient use of available space. It would be hard to squeeze any more in there. Smoke makes things work. When the smoke gets out, it stops! |
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| Zonker Guru Joined: 18/08/2012 Location: United StatesPosts: 761 |
Evening to ya Graeme..! Yep, there be a lot a "kitchen sink" on this one... It was enjoyable laying it out. (my kind of chess game) I tried to keep it small... One question needs to be answered before we go to gerber runs is the 3.3v regulator. I was looking around and basically found two types of footprints for them. For the TO-220 parts, most have the "in-gnd-out" as pins 1,2, and 3. (like the standard 78xx stuff) But there is also a group that has the "gnd-out-in" type of footprint. So, I'm looking at several PDF files to see which way to go here. I need to check if the 3v reg has enough head room, since I am feeding it from the 5v reg... (pause in posting...) 
EDIT: Yep, we need to use a low-dropout regulator. The "in-gnd-out" types seem to be based around a PNP power pass transistor and hence, the tab and center lead are GND.. They all seem to need more than 5v to operate... The low dropout regulators, (the ones that can feed off the 5v reg) all seem to be the NPN pass transistor type and hence have the "gnd-out-in" type of footprint... Whew.. Good thing I caught this...!! (my bad).. Ok, so I will make the change... |
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