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Forum Index : Microcontroller and PC projects : Proposal for correct IDC I/O pin numbers.
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donmck Guru  Joined: 09/06/2011 Location: AustraliaPosts: 1313 |
Hi Rohan, as I said earlier, you have gone with a standard because you were the first to produce boards, and if I did the same thing, I wouldn't be changing it either. My problem is getting my head around the pin numbers as they currently appear. As soon as it gets outside the box, it doesn't match in with normal electronic design convention. The manufacturers haven't changed their header designs, it is simply a 180 degree spin of the pin numbers on the PCB, which of course affects the circuit diagram. I do believe the simplest way to over come this it to have a look up table, which I have started on. All of my new boards will be made to the standard conventional pin-out. If and when I, or anybody else, produces a new PIC32 board, these will have the corrected pin-out and the schematic to suit. I say anybody else, because I see many people manufacturing a Maximite type of device. We are just leading the charge before the "Chinese Syndrome" sets in. Chinese selling on eBay. If users elect to use currently produced boards such as the Bit Wackers, etc., they will be thinking in terms of conventional pin-outs, as they won't be tied into an original Maximite schematic. The trouble is that Maximite will expand to new horizons, and find new PIC32 platforms. These people won't be interested in matching up the I/O connections on the original schematic. They will only be interested in what pins they can drive from MM basic. I know I didn't address the header situation that Stuart spoke about, as I am having enough trouble getting my head around correcting the pins to suit me, and what I feel will be most people designing to the Maximite bus in the future. If we don't correct the mistake now, it will end up like the Gerber file drama on the Arduino foot print, that users have to live with forever. I see no problems with you doing it the way that you are right now, but bear in mind what Stuart said about possibility of thousands of boards already, that will have R/A headers supplied with the kit, and soldered into the main board. As you know, yesterday, I was ready to throw a penny into the air, and see which way it came down, but after a good night's sleep, I know Stuart is right. Geoff designed the board for a R/A header, not a straight, and yes that is really the problem. You can spin a straight, you can't spin a R/A, unless you cut out the keyway slot at the bottom, but then it won't be standard. Sorry, I am going around in circles myself, and ending up with the same problem and solution. Incidentally, I think your straight female header on the Maximite board will plug into my R/A male header with a short cable on my Arduino converter board. I'll send you a kit of parts when I get them. Either way, good luck with it Rohan, Cheers Don... A supplementary question Rohan, If you left a standard R/A header on the Maximite board, would you be able to plug it into your I/O boards with a single twist of the cable? I think you can, and if that is true, then you don't have to change the R/A to straight. You do a single twist of the cable, which can be done very neatly with 45 degree bends, or tight folds, (two) so the red wire flips from one side to the other. Then you can heat shrink wrap it or whatever, or by splitting the cable in two equal parts up the center, with a sharp blade, you can twist it easily, and use a cable tie to tidy the twist up. Very interested if this works. https://www.dontronics.com |
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| rhamer Senior Member  Joined: 06/06/2011 Location: AustraliaPosts: 174 |
If the maximite has not been assembled, then putting a straight connector on it is no problem. If it has, then you can do one of 2 things, Cut a new notch in the RA connector or Make a custom cable with one end flipped. Easily achievable by crimping the cable the other way. (this is probably the Rozetta Stone answer your looking for) The cable is no harder to make, just one end is crimped with the red line on the other side. Once one of those 3 things is done, then the pinouts at the far end of the cable match the circuit. Regards Rohan Rohan Hamer HAMFIELD Software & Hardware Solutions Makers of the Maximite Expander. http://www.hamfield.com.au |
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| donmck Guru Joined: 09/06/2011 Location: AustraliaPosts: 1313 |
Yep, OK thanks Rohan. You have obviously put a lot of time and effort into it, and can overcome any situation that is thrown at you. That includes today, and into the future. As long as the bus pattern stays the same, and Geoff has assured both of us that it will, then regardless of any bodies numbers, all is well. If you look at page 2 of the manual, the pin-out matches a straight male header with Pin 1 to the bottom left. If you rotate the header 180 degrees, it matches a R/A male header, and pin 1 is at the top right of the header. I think I have that correct. :-) I'll leave it there for now then. Cheers Don... https://www.dontronics.com |
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johnbig Newbie  Joined: 23/06/2011 Location: AustraliaPosts: 21 |
For myself as I have already purchase one of Rohan's Maximite Expansion boards and plan to buy some more, I'm going to use a straight connector and plug a cable into the header before fitting the lid to the case. I'm sure this glitch will be addressed at some stage and I'm willing that if it doesnt get done this way in the future I'll just put a crossover on the end of the cable. John Leate |
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| rhamer Senior Member Joined: 06/06/2011 Location: AustraliaPosts: 174 |
Always good to hear about future sales....... Thanks John. One last check Don, you have spotted the +5 & +3.3V pin reversal error in the original SC circuit? That one cost me a whole board run...... Cheers Rohan Rohan Hamer HAMFIELD Software & Hardware Solutions Makers of the Maximite Expander. http://www.hamfield.com.au |
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| donmck Guru Joined: 09/06/2011 Location: AustraliaPosts: 1313 |
Thanks Rohan, yes were told about it, and are working on the figure on page 2 of the manual as being gospel. Cheers Don... https://www.dontronics.com |
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| donmck Guru Joined: 09/06/2011 Location: AustraliaPosts: 1313 |
Love it or hate it, I have posted the Maximite R/A Male Connector I/O Correction, before and after table at: http://www.themaximitecomputer.com/maximite-io-ra-male-heade r-pinout-correction-table/ It had to be done sooner or later. Any comments, questions, or suggestions, please let me know. Cheers Don... https://www.dontronics.com |
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| rhamer Senior Member Joined: 06/06/2011 Location: AustraliaPosts: 174 |
Well as you say, love it or hate it..... I think you have made a big mistake going that way, one that will keep on biting you. Taking the incorrect pinouts and calling them correct is silly in my view. They now don't match the circuit diagrams and will cause confusion for ever. Anyway, opinions are like..... well you know what, everyone's got one. Regards Rohan Rohan Hamer HAMFIELD Software & Hardware Solutions Makers of the Maximite Expander. http://www.hamfield.com.au |
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| donmck Guru Joined: 09/06/2011 Location: AustraliaPosts: 1313 |
Point duly noted Rohan. I think the only way we will see a real outcome or result, will be in 6 to 12 months time when our conversation becomes a part of Maximite history. As my old boss used to say "At least we agree to disagree". I hated him saying that. But then, he may have hated it when I told him what he could do with his job. :-) Cheers Don... https://www.dontronics.com |
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| rhamer Senior Member Joined: 06/06/2011 Location: AustraliaPosts: 174 |
Yeah, well.... Que Sera Sera I kind of wished we could have argued this one out over a few beers in person (well soft drink at least, as I no longer drink). I recon I could have had you and your mates on the ropes begging for mercy..... so long as you don't mind the occasional insult about being old and stubbon..... Oh and of course wrong.... Cheers Rohan Rohan Hamer HAMFIELD Software & Hardware Solutions Makers of the Maximite Expander. http://www.hamfield.com.au |
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James_From_Canb Senior Member Joined: 19/06/2011 Location: AustraliaPosts: 265 |
I have just bought 2 of Rohan's expander boards. I'm convinced he has the technical knowledge to design a board that will make my interfacing easier. And I know Don makes good products because I bought one of his USB to Serial converters after trying many rubbishy ones off eBay. It worked perfectly. When Don's products come on the market, I know they'll work. So I'm not biased, OK? Just about all the people who bought the Altech kit will be using the right-angle connector, because that's the only connector that was was supplied with the kit. I've already assembled my Maximite and don't want to try desoldering the right-hand connector and replacing it with the straight connector. As I was reading this thread I was trying to figure out why no-one had suggested a converter box - then Rohan mentioned putting the connector on the other side of the cable. That's an elegant solution that brings it back to the way it should have been. Don, if you make your gear designed to work with the bent connector, will it work with kits that have the straight connector on the back of their Maximites? Or will they have to reverse connectors. Or did I miss something earlier in the thread? 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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| donmck Guru Joined: 09/06/2011 Location: AustraliaPosts: 1313 |
Thanks for the kind words directed towards both of us James. I am designing all of my boards to plug straight into a R/A male connector, which is how Geoff designed the kit. All that is changing are the pin numbers, not the physical layout of the board or the R/A connector. Think of it this way. If I design my boards to plug into a R/A male connector, and a 1000 other board designers do the same thing, then there are no problems. When you change the foot print of the connector, you introduce problems, but Rohan and myself, disagree on this. I believe in 6 or 12 months time, there will be a gap, or a drift in opinion, like there was between Beta and VHS. Will my board plug into a Maximite with the straight male connector? I think so, but if it doesn't then you can do what Rohan does and either twist the cable, or crimp the connector on the other side. As long as you are aware of any "funnies" and act accordingly. So all Maximites will be able to be fittd to all I/O boards. I will be designing all of my boards to plug directly into the back of a standard Maximite, no changing connectors, no twisting cables, no crimping on headers in opposite directions. Let me rephrase that slightly. My first DonDuino I/O board will have 2 male, and 2 female connectors on it, as well as an Arduino foot print, a proto area, three LEDS, a VIN and a diode for VIN input polarity protection. You will be able to plug it into the Maximite in four different ways, using any of the male or female connectors. The females will plug straight in, pin for pin. The males will need a 10cm cable to allow it to plug into the Maximite. To cater for all of these combinations, a twist in one cable is required. Two very tight 45 degree folds in the cable to allow the red wire to flip from one edge to the other. What you end up with is: Plug in via a twisted cable. Boards end up 50mm (2") apart with the I/O board sitting at the back of the Maximite board. Or you can plug in via a different male, so that the I/O board will sit on top of your Maximite case using again a 10cm cable with no twist. Or you can plug in with no cable using either of the female connectors. It is a design concept that is better explained in pictures than words. After all a word is only worth a milli-picture. :-) We are close to finishing the artwork, so as soon as I have something presentable, I'll do a complete writeup. Cheers Don... https://www.dontronics.com |
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| rhamer Senior Member Joined: 06/06/2011 Location: AustraliaPosts: 174 |
Yeah, this is a difference of opinion only, in fact I'm actually a Dontronics customer and have been for years. The short story here is the only difference between our approaches is the reversal of 1 connector, and this is easily solved with one of a few different simple approaches. I only disagree with Don because I think the pin numbering should be consistent from the circuit diagram to the board and onto any plug in board. Dons view is different (but I don't want to put words in his mouth). Regards Rohan Rohan Hamer HAMFIELD Software & Hardware Solutions Makers of the Maximite Expander. http://www.hamfield.com.au |
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stuarts Senior Member Joined: 15/06/2011 Location: AustraliaPosts: 199 |
Since its the circuit diagram that is wrong, I think it is the thing that should be corrected. There are other mistakes in that drawing that need correcting as well that Geoff is aware of. I think part of the problem with the circuit diagram is that there have been several different versions of it drawn by different people. The Silicon Chip circuit diagram is different to the one published on Geoff's site. Rather than redefining the connector, shouldn't we make the circuit diagram correct so it matches the hardware? Stuart Time is nature's way of keeping everything from happening all at once. |
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| donmck Guru Joined: 09/06/2011 Location: AustraliaPosts: 1313 |
Are you allowed to say me2 on this forum. :-) Change the circuit diagram, and the problem vanishes. Cheers Don... https://www.dontronics.com |
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| rhamer Senior Member Joined: 06/06/2011 Location: AustraliaPosts: 174 |
The circuit diagram is NOT[ wrong, it is the master document that everything else was designed from. The circuit matches the board, and everything would have been fine until installing the right angle connector, when it would have been realized the footprint was 180 degrees out. Regards Rohan Rohan Hamer HAMFIELD Software & Hardware Solutions Makers of the Maximite Expander. http://www.hamfield.com.au |
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| donmck Guru Joined: 09/06/2011 Location: AustraliaPosts: 1313 |
New I/O pin-outs as revised by Geoff Graham, are posted to: http://www.themaximitecomputer.com/maximite-io-ra-male-heade r-pinout-correction-table/ Cheers Don... https://www.dontronics.com |
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| stuarts Senior Member Joined: 15/06/2011 Location: AustraliaPosts: 199 |
Rohan, the differences in the circuit digram that I was referring too were the incorrect labelling of some of the pins in the PIC itself. Not the connections to the I/O connector. Stuart Time is nature's way of keeping everything from happening all at once. |
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| rhamer Senior Member Joined: 06/06/2011 Location: AustraliaPosts: 174 |
Yes, I have conceded defeat. I still maintain it was the wrong thing to do, and confusion will now reign supreme, but it's done. Time to move on. Regards Rohan Rohan Hamer HAMFIELD Software & Hardware Solutions Makers of the Maximite Expander. http://www.hamfield.com.au |
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sparkey Senior Member Joined: 15/06/2011 Location: AustraliaPosts: 819 |
ok i have a vertical straight hedder pin sckt with pin 1 connected straight now what i would like to be explained is the i/o pins its pretty straight foward i would guess but there is always room in my mind for confusion... sorry hereditry there ...now i gather looking down on the headder pin six of the hedder is i/o (1) so from there it jumps up and down being pin (2)i/o the opposing pin(1) have i got this right ...really any body or actully every body should have fitted a vertical straight hedder in my opp ..but thats not what the poor newbies think when they solder in the right ange headder ,,,... and they get so con fused ...no bloddy wonder... regards sparkey technicians do it with least resistance |
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