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Everything posted by enl

  1. I use it as a go to for similar reasons. The price is good, dev tools are decent, peripherals well designed, still pretty close to lowest power consumption for what it can do.
  2. Well, since no one else bit yet,..... I think the root of the problem is conceptual. It works when run using vis studio because you are running it on the host. The host has a file system, Python interpreter, etc, and also has a full operating system with command shell needed for the system call. Once you upload to the tiva, there is not a full OS, filesystem, etc, no Python interpreter, and no command shell to handle the system call. If you are trying to shell on your host PC, then you need to have your code on the tiva communicate to the PC (via serial, USB, TCP/IP, wifi, other
  3. Deeper issues: The structure you have is actually fine if you want a SINGLE blink per input. Change the inner 'while's to 'if's. If you want repetitive blinking, with the inputs changing the state, the structure you have isn't really ideal, but can be used.What you might try is adding an additional condition to each of the inner while loops, similar to this: while (incomingByte =='1' && Serial.available()==0) This will cause the inner loop to end when another input is available, so that the outer loop can read it. A better overall structure for the code could be se
  4. There are several ways to interpret the root issue, so I'll pick one: When the input is '1', the first inner loop is entered, but never exited, as incomingByte is never changed within the loop. I'll spend a few minutes to address some other things in another post...
  5. I have been continuing through the 3rd, and have continued to find that it is growth from the second. The only flaw (ok, confusing thing) is the references to the (forthcoming) ancillary text. The introduction makes it clear that the `x' references are to the ancillary text, but in reading, the frequent references were not as clear... they are nominally in italics, but ONLY the chapter number (for example `3x') is, and the size and form do not stand out. On the first reading, they appeared to be unresolved editorial marks, even though I had read the introduction where the form was described.
  6. After a good bit of waffling, I decided that it is more appropriate to bring back this thread than start a new one.... Looking or information about a binocular scope.... I just picked up a Nikon SMZ-U bin scope with diascopic illuminator stand, beamsplitter (for second path, primarily camera), C-mount adapter, and camera. Unforunately no co-ax illuminator (and I am NOT paying over $1000 for one), so I will be making up a ring, eventually. Right now using an old fluorescent ring bulb desk lamp. Questions I have, among others, are primarily about the camera and the stand: Techni-quio
  7. There are several ways, and which way depends on the accuracy you need in the result and how frequently you need the result. For example, if you only need the light value every few seconds, using a counter to count the output pulses for 1sec gives you the frequency directly. If you need the light value 10 time per second, counting for 1/10s, and multiply by ten If you need the value on demand, quickly, then you can use a timer to measure the length of a single, or small number, of pulses (get the period, which is 1/f), and take a reciprocal to get frequency. The longer you can
  8. Link to Nat'n'l Inst. pae with good models for PV cells and nice graphs of characteristics: http://www.ni.com/white-paper/7230/en/ Not a ton of theory, but real good for a user. Yup, the need to check myself caught up with me. Nice to see that I dodn't make any major mstakes.... I mean didn't make any major mistakes.
  9. Solar cells have a pretty high output impedance, compared to a battery. The open circuit voltage can be a good bit higher than the design (loaded) voltage. In your application, the battery is acting to stabilize and regulate. With the battery, you get an equilibrium that is set by the battery charging rate/charge state/terminal potential/temperature relationship. This provides regulation in a manner similar to how the battery in a car or motorcycle stabilize and regulates (exactly how depends on whether the system is a generator or alternator, the regulator type-mechanical or electronic- a
  10. As a side note: I grab supplies from desktop computers on a regular basis. Modern ones generally provide 12V@5 to 15A (or more), as well as 5V@10A (or more) and 3.3V@10A (or more). They are often free from machines that have some other failure, such as hard drive, or so full of dust as to overheat the processor to failure.
  11. There are a bunch of issues here. I'll address a couple. First is the issue of isolation: In general, it is a good idea to isolate derived low voltage from the high voltage source Second is regulation: if the target required reasonably well regulated voltage, then some means is needed to ensure he regulation These lead to the commonly applied options (there are others, but they really shouldn't be implemented by someone that isn't quite conversant with power supply design and safety): Transformer voltage conversion and isolation, followed by regulation. The two traditional m
  12. I have, to this time, done close review through ch2. I have submit two errata (not bad for first print). There are about a dozen alreadty listed on the H&H site I have been quite happy with the changes overall, in particular to ch2 (bipolar transistor). I will update as I continue close reading, and would encourage any other that have the text to add their to this. There is some elaboration vs 2nd ed for switching with transistors, in particular a Schmidt trigger application, as well as a few new things appropriate for low voltage (3v) drive. They open with transistor as a switch,
  13. There was a tremendous thump on my porch. The cat spun out hard, regained traction, and headed for under the couch. I opened the door to see the postman walking away and a large box sitting there. I opened it. A gold colored book. The third. has arrived. The cat reappeared, tail fur puffed out more than I have ever seen, sniffed the book, and promptly began dismemberment of the box. Then began the odyssey: reading the thing I have only done a partial look through at this time. It will take time. There are a LOT of changes. Much more a new book than a new edition, in many ways. High
  14. Ok... wow... First: the teacher will come out Use the code tag (the <> at the top of the window) to preserve formatting for code. It also helps preserve sanity.... What algorithm are you trying to implement (insertion sort? selection sort? Bubble (shudder) sort?) Also, comments help a lot to indicate what you are trying to do, and help YOU to see problems as you write the code THat said, Your loops (the jnz at the end of the inner and the outer) are both jumping to the Swap label, and you are never doing the comparison after the first time. This is the core prob
  15. 8051 (and derivatives) will not die as long as a) there are applications for it 2) it is cheap iii) there are legacy applications where there is no reason to replace it/recode -..) manufacturers keep upgrading the peripherals to meet new needs That said, I haven't touched one in maybe 20 years. Or a PIC for a good 10.... I wasn't a great PIC fan when they hit the market, and still am not. Both architectures serve a purpose, and have done so for quite a few years, tho.
  16. OK... The data sheet (http://www. omron.com/ecb/products/pdf/en-g5v_1.pdf) shows that pins 5 and 6 are both connected to the common of the switch. Either or both can be used in your application. Lots of examples for using a transistor to control a relay... They all pretty much are the same thing, since it is a basic concept that has been around since vacuum tubes, and pretty much anyone working with electronics learns it sooner or later. Method one is build it from discrete components as in the crude attachment. Preferred for a single device. 2n3404 or 2n2222 for the relay you are usin
  17. First, DO NOT directly drive it with the microcontroller without knowing more. The output of the microcontroller (any microcontroller, not just MSP430) can be damaged driving the inductive load and current demand of the relay coil if not done properly. That said, it is tough to give details without having the part number for the relay, so I will give some generalities: The recommended way to drive the relay is to use a transistor (an npn bipolar is traditional) as a switch to ground, and use a diode across the coil to shunt the inductive kickback when shut off. Directly driving is like
  18. In addition to scraping the lower trace clean, you can also solder a short bare lead to the upper pad before soldering the inductor down. The inductor will then not sit flat. I have done similar with 30ga wire. A drop of epoxy under the component after the board is tested improves durability a lot.
  19. @@zeke Short term, yup. I think over long term, some moisture will diffuse through as long as the concentration of water vapour is lower inside the enclosure. It is amazing where water molecules can get, and what they can get through.
  20. One other point: Many materials we think of as 'waterproof' are not. Many common polymers, such as styrene plastics and polyethylene films, will allow water molecules to diffuse through, over time leading to issues even without an actual leak. This isn't a short term issue, such as when using Saran wrap to keep leftovers fresh, but over longer periods, it is an issue. Tupperware, plastic boxes sealed with gaskets, etc, are not good long term environmental protection on their own for this reason. Not my specialty, by a long shot, but some of the jobs I have been involved with got me educate
  21. The options are 1) a complete sealed setup, using the appropriate sealed penetration connectors, capable of holding against the pressure inside and out due to temp changes, 2) run the containment at a slight positive pressure, 3) ensure that moisture can get out before condensing, OR 4) pot that sucker up I have been involved in option 1 a couple of times, and it is expensive to do well. An ammo can is a decent containment, as long as the gasket is good and the temp changes arn't too great. It will breathe under great enough temp change. Option 2 is what communications providers often
  22. enl

    ADC MSP430 delay(20)

    First, theory: The wikipedia page on aliasing isn't bad. ANY sample rate that is not a sub-multiple of your sine wave frequency (without considering phase) will give you data that looks like a sine wave at some frequency or another. The RMS and offset will be the same as the wave you are sampling, but the frequency will not. The original wave can be reconstructed from undersampled data in some cases IF there is other information available. This is how many oscilloscopes used to handle very high frequencies, and some still do, using low speed D/A converters. The TIMING of the samples on a 1
  23. You need to explicitly request the fuse be blown (or the flash equivalent on those without the physical fuse). I don't have a MSP-FET, and have never done it on these processors, but I have seen it in the documentation, and done it with other families. Blowing the fuse is like blowing a fuse in your electrical box: blown is blown. Once the fuse is blown, the JTAG interface is disabled on the device. Forever. It can never be re-enabled, even by reflashing the device via BSL.There is no going back. (see, for example, SLAS722g, page 36, `JTAG Fuse', note (1)-- this is for MSP430g2X12/2X52, bu
  24. enl

    ADC MSP430 delay(20)

    As @@bluehash said, to sample he input so as to get sufficient information to reproduce it, the sample rate needs to be greater than twice the maximum frequency in the signal. First, I messed up units in my post above. I intermingles 50 microseconds and 50 milliseconds. The concept still applies and content is correct otherwise... Second, we really need to know what you are trying to do for anyone to give a better response. Are you trying to synchronise to the input? Sample it like a digital oscillloscope? other? What development tools are you using (I presume from your post that the t
  25. Cutting the pin off is effective against casual tampering, but it isn't usually that hard to get contact to even a below surface stub. Then again, anyone that is going to go that far is likely to be able to dig far enough to get by most of the built in security, as well, if they have the incentive.
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