makiyang614

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http://www.componentschip.com/
1. DS18B20 temperature interpretation

I have a problem interpretting the temperature reading of a DS18B20 chip. There is a certain situation I am not abble to resolve. This is the example temp table for the chip from the datasheet: an example for reading of -0.5*C is shown as FFF8. Cutting off the 4 LSBits we get 0x0FFF. In signed data structure that is equal to -1, not 0. How am I abble to resolve the difference between 2 readings: -0.5*C and -1.5*C? If 0xFFF8 = -0.5 then what is the form of -1.5? The table then shows an example for -10.125*C. Cutting off the 4 LSBits gives 0x0FF5 which really is -10, then there is no reason to think that there is some kind of a shift for reading negative values... Then how to test DS18B20?
2. Voltage regulator doesn't seem to be working correctly

I have a very simple lm317 adjustable voltage regulator put together with a voltage display panel to monitor it. I wanted a 1.5v source to use with the flash circuitry from a camera without having to use lots of batteries. I have the terminals on the camera circuit wired to output and ground of my regulator. When I turn the camera circuit on however, it charges extremely slowly, and the display meter cuts out. If I turn the voltage up, the display comes back on and displays between 0 and 1v. lm317 has a heatsink and doesn't feel hot. Power is fine when connected to leds. I tried adding a resistor in series with the camera circuitry in case I was drawing too much current, but then nothing happens at all.
3. Power Arduino from L298N. Connect to 5v or Vin?

I'm pretty new to Arduino and I'm making my first robot. I'm having a ball. The kit in the URL below came with most of what I need. I'd like to power the Arduino from the L298N, as I've read that its 5v connection is capable of this. My question is, do I connect that to the Vin or the 5v pin on the Arduino? My gut was to use the Vin, but I've seen some pictures that seem to show people connecting it straight to the 5v pin. That's OK to do? By the way, in case anyone's considering this kit - the main parts are great but the instructions suck and you will need much more hardware (screws, standoff, etc.) than it comes with. Thanks for any help you guys can give me. TL/DR: Connect the L298N to the 5v or Vin pin of the Arduino?
4. Taking a Class on MSP430s

I'm a computer engineering student taking a class this semester on embedded systems. The course focuses on the MSP430 microcontroller. I'd like to pick your brain for a few moments on the MSP430 and embedded boards in general. As far as things go, I've only worked with Arduino products for hobbies and personal projects. I feel that I have a basic understanding of the relationship between the arduino board, and the ATmel chip on it. I like the system becuase I can remove the ATmel and -- with only a few cents in components -- breadboard it permentantly into a project without sacrificing the arduino board. So far I've heard that the MSP430 is a very power concious device, with certain models being more frugal than others. I'm also excited to work with C and real Assembly on a physical device. I'd like to go ahead and get one of my own to work with outside of the lab, especially since I need to figure out mspgcc on my own: the lab only supports Windows operating systems. I am confused, however, by the sheer number of models and the complexity of their naming scheme, I don't know what features or model numbers to look for, and then there's the launchpad line as well. My course has so far mentioned the MSP430F2013 and the MSP430FG4618, although I don't know which one we'll be using. How careful should I be while picking out a launchpad to begin on? Will the differenent models change the C or Assembly I'm able to run on them in more impactful ways than speed/memory/etc? Can the MSP430 be switched out for another model? How practical do you feel the device is for use in permanent projects (Could I start replacing Arduinos with these once I better understand Assembly)? Also, I'd like to get a MSP-FET while it's on sale, do you have any thoughts on the device? MSP430 datesheet
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