Wednesday 21 August 2013
Today I was trying to get a Netduino 2 .NET Micro Framework microcontroller board to communicate with the ADC Pi board which we build and sell for the Raspberry Pi.
Initially the boards didn't seem to communicate so I tried to monitor the I2C signals using my Agilent MSOX2024A Oscilloscope which I purchased last month using the digital inputs which allowed me to see the clock and data lines on the SCL and SDA pins. The oscilloscope has a serial locked option for "embedded serial triggering and analysis (I²C, SPI) application" which is an extra £280 to buy. Agilent offer a 30 day free trial to unlock the extra functionality so I applied for a trial license which was processed in a few minutes and was easily installed via a USB stick.
After restarting the oscilloscope the Serial button (which seems to have a LED bug) was enabled and the data from the I2C bus was decoded in real time on the display. This seems to be a much easier way to monitor changes to the data than using my USB logic analyser which only captures a few seconds of data each time.
The screen shots below show the data on channels 1 & 2 and the decoded HEX data below.
Two data packets shown on the display
Zoomed into show a single data packet on the display
Two data packets shown on the display with the Lister display active
Single data packet shown on the display with the Lister display active
Youtube video showing realtime decode