Editing AMD Geode/Video 1/Script

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Voice: "Ideally I'd use a period accurate IBM PC"
Voice: "Ideally I'd use a period accurate IBM PC"


Expensive eBay listings scrolls past. One is shown to cost $500 AUD.
A screenshot of expensive eBay listings scrolls past. One is shown to cost $500 AUD.


Voice: "But these are really expensive"
Voice: "But these are really expensive"
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The monitor is shown again with the text "No Signal" displayed.
The monitor is shown again with the text "No Signal" displayed.


The board is shown with a chip marked "V1.18" removed from its socket.
The board is shown with a chip marked 'V1.18' removed from its socket.


Voice: "I removed the BIOS chip to see if it would still beep. It didn't."
Voice: "I removed the BIOS chip to see if it would still beep. It didn't."
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Voice: "Next I looked at the clock battery."
Voice: "Next I looked at the clock battery."


A multimeter is shown with its probes touching the positive and negative sides of the battery. It displays the value 198 millivolts.
A multimeter is shown with its probes touching the positive and negative sides of the battery. It displays the value 198mV.


Voice: "My multimeter showed it was around 200 millivolts. Completely dead."
Voice: "My multimeter showed it was around 200mV. Completely dead."


A close up of the battery being held by pliers is shown. The brand name RAYOVAC and the text "LITHIUM 3V BR1632 USA" is engraved on the chip.
A close up of the battery being held by pliers is shown. The brand name RAYOVAC and the text "LITHIUM 3V BR1632 USA" is engraved on the chip.
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Voice: "Perhaps a dead battery corrupted the BIOS settings somehow?"
Voice: "Perhaps a dead battery corrupted the BIOS settings somehow?"


The second monitor is shown again, this time with an orange plastic frog glowing on the desk near it. The monitor still says "Input Not Support".
The second monitor is shown again, this time with an orange plastic frog glowing on the desk near it. The monitor still says "Input Not Support"


Voice: "Running without the battery didn't help."
Voice: "Running without the battery didn't help."
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An oscilloscope probe goes in to one of the breadboard holes.
An oscilloscope probe goes in to one of the breadboard holes.


The oscilloscope screen shows a signal at 0 volts raising to 5 volts briefly then dropping down to -5 volts.
The oscilloscope screen shows a signal at 0v raising to 5v briefly then dropping down to -5v.


Voice: "Probing it showed the serial line was initialized, but it wasn't outputting anything."
Voice: "Probing it showed the serial line was initialized, but it wasn't outputting anything."
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Voice: "At this point I figured it was time to check the VGA signals."
Voice: "At this point I figured it was time to check the VGA signals."


An oscilloscope screen shows a 0 volt signal with shorts jump between 6.80 volts and -2.56 volts.
An oscilloscope screen shows a 0v signal with shorts jump between 6.80v and -2.56v.


Voice: "I started with vertical sync, this signal pulses every frame."
Voice: "I started with vertical sync, this signal pulses every frame."


The camera zooms in to show the frequency of the signal is 60.00 hertz and the period is 16.67 milliseconds.
The camera zooms in to show the frequency of the signal is 60.00Hz and the period is 16.67ms.


Voice: "Around 60 times a second."
Voice: "Around 60 times a second."


The oscilloscope shows a a 5 volt square wave with cursors measuring the wave. The wave is around 5 volt, peaking at 5.57 volts on the leading edge and dropping down to some unknown voltage on the trailing edge. The time a pulse of the wave takes is 40 microseconds, or 24.75 kilohertz.
The oscilloscope shows a a 5V wide square wave with cursors measuring the wave. The wave is around 5v, peaking at 5.57v on the leading edge and dropping down to some unknown voltage on the trailing edge. The time a pulse of the wave takes is 40 microseconds, or 24.75KHz.


Voice: "Looking at a single pulse we can see that it's a 5 volt square wave lasting for around 40 microseconds."
Voice: "Looking at a single pulse we can see that it's a 5 volt square wave lasting for around 40 microseconds."


The oscilloscope shows the leading edge of the square wave. It peaks at 6.64 volts and takes 228 nanoseconds to settle to 4.64 volts.
The oscilloscope shows the leading edge of the square wave. It peaks at 6.64v and takes 228ns to settle to 4.64v.


Voice: "The pulse seems to peak around 6.6 volts and takes around 230 nanoseconds to settle. This all look fine to me."
Voice: "The pulse seems to peak around 6.6 volts and takes around 230 nanoseconds to settle. This all look fine to me."
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Voice: "Next is horizontal sync."
Voice: "Next is horizontal sync."


The oscilloscope shows a 0 volt signal with longer jumps between 6.64 volts and -2.40 volts. The camera zooms in to show frequency is 75.05 kilohertz and the period is 13.33 microseconds.
The oscilloscope shows a 0v signal with longer jumps between 6.64v and -2.40v. The camera zooms in to show frequency is 75.02KHz and the period is 13.33 microseconds.


Voice: "This signal pulses every row of pixels. Around 75 kilohertz in our case."
Voice: "This signal pulses every row of pixels. Around 75 kilohertz in our case."


The oscilloscope shows a 5 volt wide square wave with cursors measuring the wave. The wave peaks at 6.55 volts at the leading edge and -2.41 volts on the trailing edge. The time a pulse takes is 1.45 microseconds, or 692.0 kilohertz.
The oscilloscope shows a 5V wide square wave with cursors measuring the wave. The wave peaks at 6.55v at the leading edge and -2.41v on the trailing edge. The time a pulse takes is 1.45 microseconds, or 692.0KHz.


Voice: "Looking closer we can see the pulse is the same voltage as the vertical sync and it lasts around 1.45 microseconds."
Voice: "Looking closer we can see the pulse is the same voltage as the vertical sync and it lasts around 1.45 microseconds."


The oscilloscope shows the leading edge of the square wave. It peaks at 6.60 volts and takes 197 nanoseconds to settle to 4.86 volts.
The oscilloscope shows the leading edge of the square wave. It peaks at 6.60v and takes 197ns to settle to 4.86v.


Voice: "The pulse takes 197 nanoseconds to settle high"
Voice: "The pulse takes 197 nanoseconds to settle high"


The oscilloscope shows the trailing edge of the square wave. It drops to -2.51 volts and takes 307 nanoseconds to settle to -51.20 millivolts.
The oscilloscope shows the trailing edge of the square wave. It drops to -2.51v and takes 307ns to settle to -51.20mV.


Voice: "and 307 nanoseconds to settle low. This looks completely fine as well."
Voice: "and 307 nanoseconds to settle low. This looks completely fine as well."
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Voice: "Ok, red signal"
Voice: "Ok, red signal"


The oscilloscope shows a flat line with a max voltage of 280 millivolts and minimum of -360 millivolts.
The oscilloscope shows a flat line with a max voltage of 280mV and minimum of -360mV.


Voice: "I don't actually see any signal"
Voice: "I don't actually see any signal"


The camera zooms to show a max voltage of 200 millivolts and minimum of -120 millivolts.
The camera zooms to show a max voltage of 200mV and minimum of -120mV.


Voice: "It just stays around 200 millivolts."
Voice: "It just stays around 200 millivolts."
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Voice: "Okay, green"
Voice: "Okay, green"


The oscilloscope shows a flat line with a max voltage of 160 millivolts and minimum of -80 millivolts.
The oscilloscope shows a flat line with a max voltage of 160mV and minimum of -80mV.


Voice: "Same thing but it's around 160 millivolts this time."
Voice: "Same thing but it's around 160 millivolts this time."
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Voice: "What about blue?"
Voice: "What about blue?"


The oscilloscope shows a flat line with a max voltage of 280 millivolts and minimum of -160 millivolts.
The oscilloscope shows a flat line with a max voltage of 280mV and minimum of -160mV.


Voice: "It's the same thing as red and green. These all should be much higher."
Voice: "It's the same thing as red and green. These all should be much higher."
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== SD card adapter ==
== SD card adapter ==
An IDE to SD card adapter is shown on the table, with an SD card inserted. Its circuit board is black and yellow and the main chip on the board has a "QC Passed" sticker that changes colour based on the angle.
An IDE to SD card adapter is shown on the table, with an SD card inserted. Its circuit board is black and yellow and the main chip on the board has a 'QC Passed' sticker that changes color based on the angle.


Voice: "I did try to connect an IDE to SD card adapter so I could boot from it."
Voice: "I did try to connect an IDE to SD card adapter so I could boot from it."
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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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