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AMD Geode/Video 1/Script
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== Probing BGA signals == A manual page is shown of the BGA pins under the Geode chip. Along the left outer edge is a series of pins: DAVdd, DAVdd, DVREF, DRSET, VAVdd, DOTREF. Voice: "I noticed that most of the signals here are on the outside of the chip." A mess of junk is shown on a desk. A lamps shines light on the board. The power supply runs cables to a molex splitter which run to the board. A contraption used to hold things has a circuit board of a webcam attached pointing at the board, with plastic to insulate the holder and a USB wire trailing away. A pair of tweezers pokes under the CPU on the board with one end and connects to an oscilloscope probe from the other end. The tweezers are held open by a plastic craft knife cap. The scope probe balances on a spool of magnet wire, with its ground wire connected to the Molex splitter too. All of this is cramped and barely holding together. Voice: "So I set up a makeshift BGA probe on my desk and scoped the available signals." A close up webcam shot of tweezers poking a ball under the chip is shown. An oscilloscope shows a line with a voltage around 3.36 volt DC, the RMS value being 3.28 volts. Voice: "The first DAVdd ball hung around 3.3 volts which is correct." The tweezers move to an adjacent ball under the chip. An oscilloscope shows a line with a voltage around 3.44 volts, the RMS value being 3.28 volts. Voice: "The second DAVdd ball did about the same." The tweezers move to the next ball. An oscilloscope shows a line with a voltage around 1.32 volts, the RMS value being 1.22 volts. Voice: "The DVREF ball hung around 1.22 volts which is about right." The tweezers move yet again. An oscilloscope shows a line with a voltage around 40 millivolts, the RMS value being 0 millivolts. Voice: "The DRSET ball was around 40 millivolts which is a bit high." The tweezers move again. An oscilloscope shows a line with a voltage around 3.36 volts, the RMS value being 3.32 volts. Voice: "The VAVdd ball hung around 3.3 volts which is fine." The tweezers move again. An oscilloscope shows a 48.08 megahertz sine wave peaking at 3.92 volts, the RMS varying being 2.40 volts and 1.92 volts. Voice: "The DOTREF ball had a 3.3 volt 48 megahertz sine wave on it. It should be a square wave I think but this might be a scope artifact." A somewhat close up shot of the board is shown with a focus on the area just inspected. Voice: "Overall though everything seems fine."
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