> > When you design low cost hardware, you have to make certain decisions to > get the cost down. > > 1) As few components as possible. > 2) Limit the application. Only one application, > 3) Push as much cost outside, for example the power supply. > 4) Lowest cost components. > 5) Limit the features. > 6) Cut the profit. > > Yes, there are several things I could have done different. Many of these > no one has even identified. But if I had, you would not have bought it > because it cost too much. After all hardware is supposed to be cheap. That > is where the value is, in the price. Not the value.. > > Nobody asked how I took it from $89 to $49. They just bought them up and > complained that it didn't do all the things they wanted it to do for $49. > > If anyone of you want to change the design, add more features, make it > more robust, add more cost, increase the price, manufacture it and sell it, > by all means, go ahead. I am sure there will b a few folks that value the > hardware and recognize that value, and will pay for it. > > But, I suspect the majority will complain that it is too expensive and > will stay with the BBB and instead ask how to flash the latest image in the > BBB and why does my my GPIO does not work.. >
Exactly, or close enough to what I was getting at. So Instead of me saying: "Pay no attention to John, as he tends to pontificate on others comments, and has no idea what the hell he is talking about." Let me just say that I figured Gerald had the sole purpose of designing this board to work "good enough" while remaining within a specified price range. e.g. it works, and it's cheap. On Mon, Jul 4, 2016 at 4:02 PM, Gerald Coley <[email protected]> wrote: > When you design low cost hardware, you have to make certain decisions to > get the cost down. > > 1) As few components as possible. > 2) Limit the application. Only one application, > 3) Push as much cost outside, for example the power supply. > 4) Lowest cost components. > 5) Limit the features. > 6) Cut the profit. > > Yes, there are several things I could have done different. Many of these > no one has even identified. But if I had, you would not have bought it > because it cost too much. After all hardware is supposed to be cheap. That > is where the value is, in the price. Not the value.. > > Nobody asked how I took it from $89 to $49. They just bought them up and > complained that it didn't do all the things they wanted it to do for $49. > > If anyone of you want to change the design, add more features, make it > more robust, add more cost, increase the price, manufacture it and sell it, > by all means, go ahead. I am sure there will b a few folks that value the > hardware and recognize that value, and will pay for it. > > But, I suspect the majority will complain that it is too expensive and > will stay with the BBB and instead ask how to flash the latest image in the > BBB and why does my my GPIO does not work.. > > > On Mon, Jul 4, 2016 at 5:46 PM, John Syne <[email protected]> wrote: > >> Harvey, you raised several very good points. I cannot say I disagree with >> anything you said. >> >> Regards, >> John >> >> >> >> >> > On Jul 4, 2016, at 3:36 PM, Harvey White <[email protected]> >> wrote: >> > >> > On Mon, 4 Jul 2016 15:13:00 -0700, you wrote: >> > >> >> Pay no attention to William. You comments are welcome and Gerald has >> accepted your comments as valuable input by thanking your for your >> feedback. Now, let me address your concerns: >> > >> > From my own engineering standpoint (and opinions will, of course, >> > vary): >> >> >> >> 1) The power supply used to power the BBB should be selected so that >> it does not damage the BBB, so a 2A power supply was specified. If you wish >> to change that specification, then the onus is on you to verify that a 4A >> power supply will not damage the BBB. Your conclusion that is may damage >> the BBB means that you should not use a 4A power supply. In addition, a >> power supply that is spec’d at 4A should not shutdown when it sees a 4A >> load, but rather, it should current limit at 4A. If the power supply is >> spec’d at 4A, then 4A should not be treated as a short circuit. >> > >> > I would have designed the power supply circuitry so that with a power >> > supply of appropriate minimum rating, the maximum rating would not >> > have mattered. Using a power supply with a maximum current rating to >> > avoid damaging circuitry is not (again, IMHO) the best solution. If, >> > because of economic considerations, that decision is made, then it is >> > imperative of the designer to put this information specifically in the >> > power supply recommendations. Not doing this leads to damage, doing >> > this puts the responsibility on the user. Is this a "before the >> > design/after the design"? I don't know, and I don't remember (either >> > way) if this warning was ever in the power supply requirements. >> > Hindsight is 20/20, of course. If it's that important, then perhaps >> > the documentation needs to be changed. Decision not up to me. >> > >> > >> >> 2) The TI spec for the TPS65217C is a general recommendation as they >> are unaware of how you are going to use the part. The BBB SYS_5V powers >> several subsystems, including HDMI, I/O (VDD_3V3B) and USB. Clearly you >> could move the 100uF to the other side of the TPS2051, but then you need an >> additional capacitor on the SYS_5V which increases the cost and doesn’t >> provide any clear benefit, if you choose the correct power supply. >> > >> > "correct power supply" bothers me. I'm familiar with minimum current >> > capacity, voltage limits, short circuit current limits (infrequently >> > applied). Again, "a 4 amp power supply will allow the board to damage >> > itself, so we depend on a 2 amp maximum supply to avoid damage." This >> > could be discussed a bit.... >> > >> > >> >> 3) As Gerald has pointed out, the BBB is just a reference design. It >> was designed as a low cost solution which meant that tradeoffs were >> required to keep the price low. Clearly things could have been done >> differently, but then the BBB price would have been much higher and the >> board larger. Given that most users would probably not need these extra >> features, they were not incorporated into the current design. There are >> several spinoffs of the BBB, some with wifi, some with more RAM, etc, but >> none have been as successful as the BBB. >> > >> > Hmmm, well, perhaps (although not required) it might be nice to know >> > what the engineering limitations are of the design. >> > >> > I've seen 1) the ones I know about, and 2) the ones I haven't found >> > out yet... and 3) the ones people are going to have to tell me >> > about... >> > >> > and I do like paranoid designs..... >> > >> > Harvey >> > >> > >> >> 4) While I have provided Gerald input into both the BBB and >> BeagleBoard-x15 designs, I ultimately defer to his judgement because he has >> the track record or having designed several products that are very >> successful. >> >> >> >> From my prospective, the BBB design is good, but your input was none >> the less valuable. >> >> >> >> Regards, >> >> John >> >> >> >> >> >> >> >> >> >>> On Jul 4, 2016, at 2:11 PM, William Hermans <[email protected]> >> wrote: >> >>> >> >>> kzsoltkzsolt, >> >>> >> >>> I would like to point out to you that you're talking to *the* person >> who designed the beaglebones, who also used to work for Texas Instruments >> at some point in his career. Someone who has made his designs free of >> charge to the public, which he has made perfectly clear to you in these >> post that you're free to change and use for your own personal use. >> >>> >> >>> So, telling him things, he probably already knows, in hopes of making >> yourself looks good. Actually make you look like a "know it all". e.g. it >> doesn't make you look good. >> >>> >> >>> SO perhaps you should realize that Gerald is probably well aware of >> what you're trying to discuss here, but is unwilling to change for various >> reasons. Reason, that you, I, or the next person do not need to understand. >> Because we can change to designs to our own liking if we so wish. >> >>> >> >>> On Mon, Jul 4, 2016 at 1:55 PM, Gerald Coley <[email protected] >> <mailto:[email protected]>> wrote: >> >>> Thank you for your feedback. >> >>> >> >>> Gerald >> >>> >> >>> On Mon, Jul 4, 2016 at 3:18 PM, <[email protected] <mailto: >> [email protected]>> wrote: >> >>> First of all making changes on design "tomorrow" is irresponsible, so >> I never request it. But good to know where is some "leak" in design. For >> example it is help to make workaround. >> >>> >> >>> "TI did not write that specification" >> >>> No, but use it in all reference design. See TI TPS20x1 PDS >> application information. See for example TPS2051 docu Fig 33. >> >>> >> >>> "If you put the CAP after the switch then ..." >> >>> Then why CAP placed OUT of PDS in all TI application information? >> >>> Because PDS has soft start feature which prevent overload IN (BBB SYS >> power rail). See for example TPS2051 docu Fig 4 and 8. >> >>> Fig 8 is perfect draw for this. The soft start feature limit charge >> of 100uF to 0,5A, therefore current never exceed USB1 and 2 current limit, >> therefore no dip on IN. >> >>> This is one main function of PDS. >> >>> >> >>> "I did not design the board for your application" >> >>> It is not required. But during research work to specify our problem I >> found many topic where users discover mysterious problems with power >> supply, and try to found a right one for BBB. This can be originated from >> startup current peak. >> >>> >> >>> >> >>> -- >> >>> For more options, visit http://beagleboard.org/discuss < >> http://beagleboard.org/discuss> >> >>> --- >> >>> You received this message because you are subscribed to the Google >> Groups "BeagleBoard" group. >> >>> To unsubscribe from this group and stop receiving emails from it, >> send an email to [email protected]<mailto: >> [email protected]>. >> >>> To view this discussion on the web visit >> https://groups.google.com/d/msgid/beagleboard/b974f98a-0cff-4380-af1f-9ce5db9e199f%40googlegroups.com >> < >> https://groups.google.com/d/msgid/beagleboard/b974f98a-0cff-4380-af1f-9ce5db9e199f%40googlegroups.com?utm_medium=email&utm_source=footer >> >. >> >>> >> >>> For more options, visit https://groups.google.com/d/optout < >> https://groups.google.com/d/optout>. >> >>> >> >>> >> >>> >> >>> -- >> >>> Gerald >> >>> >> >>> [email protected] <mailto:[email protected]> >> >>> http://beagleboard.org/ <http://beagleboard.org/> >> >>> [email protected] <mailto:[email protected]> >> >>> >> >>> >> >>> -- >> >>> For more options, visit http://beagleboard.org/discuss < >> http://beagleboard.org/discuss> >> >>> --- >> >>> You received this message because you are subscribed to the Google >> Groups "BeagleBoard" group. >> >>> To unsubscribe from this group and stop receiving emails from it, >> send an email to [email protected]<mailto: >> [email protected]>. >> >>> To view this discussion on the web visit >> https://groups.google.com/d/msgid/beagleboard/CAHK_S%2BcAH_U%3DVtJmLq62wrVPmRg8%2Bn27YjWM_oeorZezSTKorQ%40mail.gmail.com >> < >> https://groups.google.com/d/msgid/beagleboard/CAHK_S%2BcAH_U%3DVtJmLq62wrVPmRg8%2Bn27YjWM_oeorZezSTKorQ%40mail.gmail.com?utm_medium=email&utm_source=footer >> >. >> >>> >> >>> For more options, visit https://groups.google.com/d/optout < >> https://groups.google.com/d/optout>. >> >>> >> >>> >> >>> -- >> >>> For more options, visit http://beagleboard.org/discuss < >> http://beagleboard.org/discuss> >> >>> --- >> >>> You received this message because you are subscribed to the Google >> Groups "BeagleBoard" group. >> >>> To unsubscribe from this group and stop receiving emails from it, >> send an email to [email protected]<mailto: >> [email protected]>. >> >>> To view this discussion on the web visit >> https://groups.google.com/d/msgid/beagleboard/CALHSORo-TL2x_vUEni%2B-daiSEQXxLUU_N5p%2BEh%2Bt6tzpuuPT0g%40mail.gmail.com >> < >> https://groups.google.com/d/msgid/beagleboard/CALHSORo-TL2x_vUEni%2B-daiSEQXxLUU_N5p%2BEh%2Bt6tzpuuPT0g%40mail.gmail.com?utm_medium=email&utm_source=footer >> >. >> >>> For more options, visit https://groups.google.com/d/optout < >> https://groups.google.com/d/optout>. >> > >> > -- >> > For more options, visit http://beagleboard.org/discuss >> > --- >> > You received this message because you are subscribed to the Google >> Groups "BeagleBoard" group. >> > To unsubscribe from this group and stop receiving emails from it, send >> an email to [email protected]. >> > To view this discussion on the web visit >> https://groups.google.com/d/msgid/beagleboard/cjolnb1s1bddugkd1v6c4jeqm1a0mhmvhh%404ax.com >> . >> > For more options, visit https://groups.google.com/d/optout. >> >> -- >> For more options, visit http://beagleboard.org/discuss >> --- >> You received this message because you are subscribed to the Google Groups >> "BeagleBoard" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/beagleboard/70E6C922-DEB1-451D-A72C-AC4C2EA2DF06%40gmail.com >> . >> For more options, visit https://groups.google.com/d/optout. >> > > > > -- > Gerald > > [email protected] > http://beagleboard.org/ > [email protected] > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/beagleboard/CAHK_S%2BcSGF0gqB5yJ4EQdbYHMvS04cNOej%2B1Bw8L5y7W6AnH4A%40mail.gmail.com > <https://groups.google.com/d/msgid/beagleboard/CAHK_S%2BcSGF0gqB5yJ4EQdbYHMvS04cNOej%2B1Bw8L5y7W6AnH4A%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > > For more options, visit https://groups.google.com/d/optout. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CALHSORqsL%2BGaeLtV4AVi6yK4GYpGfKRRzhArCvuNAqC2yOpEsg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
