On Saturday, January 18, 2014 4:02:46 PM UTC-5, Skywise wrote:   
   > haitic1@gmail.com wrote in   
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   > news:6c657e9e-c9ead0df@googlegroups.com:   
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   > > First, what kind of ADC does it have?   
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   > > Out of curiosity, have you used the Propeller for any sensor ADC?   
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   > Well, I'm not a pro at this and have made only a few projects.   
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   > As I said, I'm a tinkerer. Haven't worked in electronics for   
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   > close to 20 years now. My electronics training was decades ago   
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   > and I was always much better at the digital side of things than   
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   > analog. But I have always done programming as a hobby as well   
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   > so that helps when playing with MCUs.   
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   > It does not have a built in ADC, but I do know that it can be   
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   > done using the counter/timers and some external R/C. There are   
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   > sample codes. Not really sure of the accuracy of that method.   
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   > However, for one of my projects I preferred instead to use some   
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   > TI ADC chips to read a joystick. I do recall having a lot of   
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   > analog noise but I cleaned it up in software by averaging results   
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   > over many samples. Of course, this was all on a breadboard so   
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   > that was probably the source of my noise.   
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   > Nothing super fancy, nor was I going for super accuracy, but I   
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   > see no reason why it's not possible with a properly designed   
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   > circuit.   
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   > The nice thing about having multiple cores is that you don't   
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   > need to muck about with interupts. In fact, there are no   
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   > interupts on the propeller.   
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   > I had one core running an assembly program to continuously read   
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   > the ADC, do the averaging, and dump the values into common memory.   
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   > There is memory for each core, and memory common to all cores.   
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   > Then the main program, running in another core, would just access   
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   > the common memory whenever it needed to 'read' the joystick. The   
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   > main program was written in propellers high level 'Spin' language.   
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   > My most recent tinkering was to drive some TI TLC5946 LED video   
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   > driver chips for full 'analog' brightness control of RGB LED's.   
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   > Again, having multiple cores helped do things simultaneously.   
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   > One core using ASM is used to drive the chips continuously. It   
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   > reads the RGB values from common memory and drives the chips   
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   > continously. It also uses the timer circuitry from the same core   
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   > to generate the grayscale clock the chips need to PWM the LEDs.   
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   > The counter/timers can be used to generate signals which run   
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   > independantly of the core (set and forget).   
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   > The fun part of that project was taking into account the   
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   > nonlinearity of the eye to perceived brightness. The ASM code   
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   > uses a lookup table to convert the 8-bit RGB values to a 12-bit   
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   > value for the driver chips. Making the lookup table was fun.   
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   > But that's pretty much the "state of the art" that I personally   
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   > have done.   
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   > There is plenty of documentation on their website so if you   
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   > get the chance, I think it'll be worth your time to at least   
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   > investigate.   
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   >   
   > Brian   
   >   
   > --   
   >   
   > http://www.earthwaves.org/forum/index.php - Earthquake prediction & Earth   
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   > Sciences   
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   > http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism   
   >   
   > Sed quis custodiet ipsos Custodes?   
      
   Thanks for application info. How fast was your ADC running? Do you remember   
   which Ti adc it was? I have seen recommendations to just put a cap to ground   
   on the ADC input, depending on input BW. Potentiometers in joy sticks, etc.   
   are also quite noisy.   
   I'm still thinking what use an 8 core 32 bit mcu is...Amazing thing.   
   jb   
      
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