Editing AMD Geode/Video 1/Script

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== Molex USB adapter ==
== Molex USB adapter ==
An eBay page showing a cable with a Molex end and a USB end is visible. The item is listed as "5V USB Power to 4Pin Molex(2Pin Wired) Cable 50cm". The price is listed as $8.59 AUD. The image has arrows pointing to the USB and Molex end, subtitled "USB Power 5V" and "Molex(2Pin wired) 5V" respectively.
An eBay page showing a cable with a Molex end and a USB end is visible. The item is listed as '5V USB Power to 4Pin Molex(2Pin Wired) Cable 50cm'. The price is listed as $8.59 AUD. The image has arrows pointing to the USB and Molex end, subtitled 'USB Power 5V' and 'Molex(2Pin wired) 5V' respectively.


Voice: "As an aside I bought a USB to Molex adapter for powering the board."
Voice: "As an aside I bought a USB to Molex adapter for powering the board."


The adapter plugged in to the Molex splitter is shown. A screwdriver gestures at how when connected the 5 volts red wire of the adapter is connected to the 12 volts yellow wire of the splitter, instead of the 5V red wire on the splitter.
The adapter plugged in to the Molex splitter is shown. A screwdriver gestures at how when connected the 5V red wire of the adapter is connected to the 12V yellow wire of the splitter, instead of the 5V red wire on the splitter.


Voice: "But it connects the 5 volt USB pins to the 12 volt Molex rail."
Voice: "But it connects the 5 volt USB pins to the 12 volt Molex rail."
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Voice: "Step five: Check that it looks good."
Voice: "Step five: Check that it looks good."


A hand plugs the adapter in to the single-board computer and the USB end in to a USB power supply. It has a screen showing the current voltage of the port which is 5 volts, but quickly switches to 1 amp when the board powers on.
A hand plugs the adapter in to the single-board computer and the USB end in to a USB power supply. It has a screen showing the current voltage of the port which is 5v, but quickly switches to 1A when the board powers on.


Voice: "I connected the board to a USB power supply as a test. It seemed to boot fine to me."
Voice: "I connected the board to a USB power supply as a test. It seemed to boot fine to me."
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== USB power meter ==
== USB power meter ==
The power supply is shown upside down. A USB power meter is inserted with the adapter cable connected to it. The meter shows the voltage as 4.97 volts and amperage around 1.1 amps.
The power supply is shown upside down. A USB power meter is inserted with the adapter cable connected to it. The meter shows the voltage 4.97V and amperage around 1.1A.


Voice: "Just for fun I plugged the board in to a USB power meter."
Voice: "Just for fun I plugged the board in to a USB power meter."


The meter shows a graph of the current consumption. The graph starts at 0.9 amps and fluctuates between 1 amp and 1.4 amps before settling down to 1 amp.
The meter shows a graph of the current consumption. The graph starts at 0.9A and fluctuates between 1A and 1.4A before settling down to 1A.


Voice: "It verified the system hangs around 1 amp with 1.5 amp peaks."
Voice: "It verified the system hangs around 1 amp with 1.5 amp peaks."
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A page shows a table of signals and their types, including HSYNC, VSYNC, DVREF, DRSET, DAVdd, DAVss, RED, GREEN.
A page shows a table of signals and their types, including HSYNC, VSYNC, DVREF, DRSET, DAVdd, DAVss, RED, GREEN.


Voice: "The DAC needs a 1.235 volt voltage reference and a 1.21K ohm current setting resistor."
Voice: "The DAC needs a 1.235 voltage reference and a 1.21K ohm current setting resistor."


A page shows a download page of the file XO-1-Schematics.pdf with the description "Schematics for the C2 version of the XO-1 Laptop".
A page shows a download page of the file XO-1-Schematics.pdf with the description "Schematics for the C2 version of the XO-1 Laptop".
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Voice: "I looked up other schematics online for boards that use the Geode. I found the OLPC XO-1 board."
Voice: "I looked up other schematics online for boards that use the Geode. I found the OLPC XO-1 board."


A screenshot of schematics relating to the DVREF, DRSET and DAVdd and DAVss pins is displayed. In order to generate 1.235 volts a resistor divider is used based on the 3.3 volt rail, with various bypass capacitors smoothing out the 3.3 volt rail and feeding it to the DAV pins. The DRSET pin has a 1.21 kiloohm resistor connected between it and ground.
A screenshot of schematics relating to the DVREF, DRSET and DAVdd and DAVss pins is displayed. In order to generate 1.235V a resistor divider is used based on the 3.3v rail, with various bypass capacitors smoothing out the 3.3v rail and feeding it to the DAV pins. The DRSET pin has a 1.21K resistor connected between it and ground.


Voice: "Looking at the schematic I figure if anything's going to break it would be the voltage divider used for DVREF."
Voice: "Looking at the schematic I figure if anything's going to break it would be the voltage divider used for DVREF."


== Finding DVREF ==
== Finding VREF ==
Various shots of multimeter probes touching ends of resistors on the board are shown.
Various shots of multimeter probes touching ends of resistors on the board are shown.


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Voice: "Eventually I didn't find the divider but I did find a 1.22 volt voltage reference."
Voice: "Eventually I didn't find the divider but I did find a 1.22 volt voltage reference."


A diagram showing how the components fit together is shown. DAVdd connects to the LM4041AIM3-1.2 voltage reference. From the 1.22 volt reference a 0.25 nanofarad capacitor and 10 kiloohm resistor in parallel run to DVREF. The 1.21 kiloohm resistor follows from the DVREF capacitor and resistor to the DRSET pin.
A diagram showing how the components fit together is shown. DAVdd connects to the LM4041AIM3-1.2 voltage reference. From the 1.22v reference a 0.25nF capacitor and 10k resistor in parallel run to DVREF. The 1.21k resistor follows from the DVREF capacitor and resistor to the DRSET pin.


Voice: "I made this diagram of the general area for reference."
Voice: "I made this diagram of the general area for reference."
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Voice: "So I set up a makeshift BGA probe on my desk and scoped the available signals."
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.
A close up webcam shot of tweezers poking a ball under the chip is shown. An oscilloscope shows a line with a voltage around 3.36v DC, the RMS value being 3.28v.


Voice: "The first DAVdd ball hung around 3.3 volts which is correct."
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.
The tweezers move to an adjacent ball under the chip. An oscilloscope shows a line with a voltage around 3.44v, the RMS value being 3.28v.


Voice: "The second DAVdd ball did about the same."
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.
The tweezers move to the next ball. An oscilloscope shows a line with a voltage around 1.32v, the RMS value being 1.22v.


Voice: "The DVREF ball hung around 1.22 volts which is about right."
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.
The tweezers move yet again. An oscilloscope shows a line with a voltage around 40mV, the RMS value being 0mV.


Voice: "The DRSET ball was around 40 millivolts which is a bit high."
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.
The tweezers move again. An oscilloscope shows a line with a voltage around 3.36v, the RMS value being 3.32v.


Voice: "The VAVdd ball hung around 3.3 volts which is fine."
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.
The tweezers move again. An oscilloscope shows a 48.08mhz sine wave peaking at 3.92v, the RMS varying being 2.40v and 1.92v.


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."
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."
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== Booting Linux ==
== Booting Linux ==
A CompactFlash card is held to the camera. On one side it says "Memory Card" with space to write the description, on the other side it says "CompactFlash Digital Memory Card 16 GB Memory Card". No branding is visible aside from "Copyright 2003 Memory Technology Company" is shown.
A CompactFlash card is held to the camera. On one side it says 'Memory Card' with space to write the description, on the other side it says 'CompactFlash Digital Memory Card 16 GB Memory Card'. No branding is visible aside from 'Copyright 2003 Memory Technology Company' is shown.


Voice: "My CompactFlash card finally arrived."
Voice: "My CompactFlash card finally arrived."


A DB9 cable is shown connected to the board with the text "NULL" scribbled on it in marker.
A DB9 cable is shown connected to the board with the text 'NULL' scribble on it in marker.


A screen shows the text "Loading bzImage... ok" and <nowiki>''</nowiki>Loading initramfs-fc2+...ok"
A screen shows the text 'Loading bzImage... ok' and <nowiki>''</nowiki>Loading initramfs-fc2+...ok'


Voice: "So with the help of a null modem cable I was able to boot Linux."
Voice: "So with the help of a null modem cable I was able to boot Linux."


The screen starts to print a bunch of text, such as "Linux version 5.16.0-rc2+ (jookia@titan) (gcc (GCC) 11.1.0, GNU ld (GNU Binutils) 2.36.1) #1 SMP PREEMPT Mon Nov 29 17:34:47 AEDT 2021"
The screen starts to print a bunch of text, such as 'Linux version 5.16.0-rc2+ (jookia@titan) (gcc (GCC) 11.1.0, GNU ld (GNU Binutils) 2.36.1) #1 SMP PREEMPT Mon Nov 29 17:34:47 AEDT 2021'


Voice: "Specifically, Alpine Linux with a custom built kernel with the Geode video driver enabled."
Voice: "Specifically, Alpine Linux with a custom built kernel with the Geode video driver enabled."


Another screen is black but then blinks on, with the text lines "Welcome to Alpine Linux 3.15", "Kernel 5.16.0-rc2+ on an i586 (/dev/tty1)" and "localhost login: " visible in the bottom left, with the first few letters of each line cut off.
Another screen is black but then blinks on, with the text 'Welcome to Alpine Linux 3.15', 'Kernel 5.16.0-rc2+ on an i586 (/dev/tty1)' and 'localhost login: _' visible in the bottom left, with the first few letters of each line cut off.


Voice: "After a little white booting we get... VGA output?"
Voice: "After a little white booting we get... VGA output?"
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Voice: "It's a wrongly positioned login prompt?"
Voice: "It's a wrongly positioned login prompt?"


A shot from later shows the text barely visible against the screen's backlight black colour. The text shimmers with analog interference of some kind.
A shot from later shows the text barely visible against the screen's backlight black color. The text shimmers with analog interference of some kind.


Voice: "Thought after a few minutes it starts to fade."
Voice: "Thought after a few minutes it starts to fade."
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Voice: "I took a look at the red signal under an oscilloscope."
Voice: "I took a look at the red signal under an oscilloscope."


An oscilloscope shows a flat line with a voltage peak of 180 millivolts and RMS of 0 volts.
An oscilloscope shows a flat line with a voltage peak of 180mV and RMS of 0.


Voice: "It looked the same as before with no signal."
Voice: "It looked the same as before with no signal."
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Voice: "But zooming in shows there's something clearly there, it's just very very weak."
Voice: "But zooming in shows there's something clearly there, it's just very very weak."


The scope shows the signal has a peak voltage of 15.60 millivolts and an RMS of 6.80 millivolts. The signal regularly jumps up and down. The scope zooms out to show a larger length of the signal revealing a square wave.
The scope shows the signal has a peak voltage of 15.60mV and an RMS of 6.80mV. The signal regularly jumps up and down. The scope zooms out to show a larger length of the signal revealing a square wave.


Voice: "The signal even looks like it's bouncing but changing the time scale shows it's actually a square wave."
Voice: "The signal even looks like it's bouncing but changing the time scale shows it's actually a square wave."


The scope pauses on a snapshot of the square wave. The frequency is 51.58 hertz, with a peak of 15.20 millivolts.
The scope pauses on a snapshot of the square wave. The frequency is 51.58Hz, with a peak of 15.20mV.


Voice: "A 15 millivolt square wave that runs at 51.58 hertz. Wow."
Voice: "A 15 millivolt square wave that runs at 51.58 hertz. Wow."
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The soldering iron once again tries to solder the capacitor but manages to rip away the pad it was soldering to.
The soldering iron once again tries to solder the capacitor but manages to rip away the pad it was soldering to.


Voice: "This ended up with me ripping the only other pad I had left." followed by groaning noises.
Voice: "This ended up with me ripping the only other pad I had left." (groaning noises)


A cleaned board is shown with no soldered equipment visible.
A cleaned board is shown with no soldered equipment visible.
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