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CPP_Technologist

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About CPP_Technologist

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  1. It could be some sort of noise problem, however it certainly didn't exist when I used this circuit with the arduino, (at 5V, so maybe S/N ratio was small enough or the arduino just has more hysteresis). I think the version of Energia code I'm using may have a bug: I decided to break the circuit up and have one phototransistor trigger the rising edge interrupt pin and one phototransistor trigger the falling edge interrupt pin. I've noticed that they both end up triggering their respective interrupts when I remove my finger from their light beam-- it seems that they are both triggeri
  2. Sorry this took so long, but my new code using the suggestions above still registers no difference in the time between the rising and falling edges of the pulse. Even if I generate a very long pulse, like a second or so, the time between the rising and falling edges is shown as zero. Extra Info: I am making these pulses by placing my finger between a phototransistor and a light source. The phototransistor is running in "open collector" mode with a 1K resistor. When my finger blocks the light source, I should see the phototransistor output go high, (because this is an inverting config
  3. I am trying to detect the width of a pulse signal (that should be anywhere from 1ms to 20ms wide) using two ISRs on the MSP430G2553. One ISR is triggered by the rising edge, and the other by the falling edge. The first ISR reads micros() and stores the value in a variable called Time1. The second ISR reads micros() and stores the value in a variable called Time2. The pulse width of the signal is equal to Time2-Time1. The problem is, Time1 and Time2 always end up being equal, even though they are read in two different ISRs on two separate signal edges-- this should be impossible. Any
  4. Don't know why this posted with so many @ such and such. I didn't write that. Anyway, I got this working with the code above. I rewired everything and it started working, so I must have had a bad connection somewhere.
  5. Hello All! I'm having trouble achieving I2C communication with Sparkfun's MPR121 I2C capacitive touch sensor breakout board. I've used the breakout board (and code) many times before with the Arduino, but for some reason I can't get it to work with the MSP430G2553 and Energia. I'm using an MPR121 library found at http://bildr.org/2011/05/mpr121_arduino/ to help with register configuration. My code compiles fine, but I'm trying to print the output from the touch sensor to the serial monitor and nothing is showing up, so I'm assuming the touch sensor isn't working. I kno
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