Mike P

I was breadboarding a 24 bit ADC with integral current sources. I wanted it for high resolution temperature sensing (4-wire PT100). The same device would be well suited for load cells and strain gauges(used for measuring force/weigh/pressure/stress) I was testing both the exas instruments ADS1247 or Analog device AD7794. Unfortunately the project was shelved.

I must have been half asleep when I wrote my earlier response. It was full of mistakes. I've edited it and fixed the errors. Regards, Mike Paauwe

If you look at Stefan W's oscilliscope images you will see why an "almost high enough" voltage level could cause multiple clock triggers. look at the spike at the leading edge of the clock pulse. If you looked at the signal even closer you would see a decaying oscillation that could cause several false clock pulses to be received.

If you have time I would be very interested to see if the LED strip works without the level conversion chip. I mean with the SDI , SCLK and GND connnected directly to the netduino. Regards, Mike Paauwe

What you are describing sounds very much like some false triggerring on the clock pin. Between the write transactions the MOSI line goes high. That explains why you are gettin white LEDs at the start. You are getting a number of clock pulses being detected while the clock is supposed to be low. Try increasing the thread.sleep to 500ms. You should see the LED states change instantaneously every 1/2 a second and be stable between changes. A couple more questions. The 2A @ 5V power supply, is it a Switch mode power supply or a plug-pack or wall-wart type power supply? Some of these have very little smoothing and ripple on the supply line might be causing the unwanted clock triggers You definitely need the gnd pin from the data connector connected to the netduino. The gnd pin of the power connector should already be connected to the ground pin of the data connector internally on the LED strip Perhaps if you can take a photo of the setup.