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How to create a new schematic symbol in the Eagle editor
This tutorial describes how to create a custom schematic symbol in the CadSoft Eagle editor. It assumes that you have some familiarity with Eagle and just want to create a schematic (not a PCB), but...
View ArticleObama on sorting 1M integers: Bubble sort the wrong way to go
Recently StackOverflow and HackerNews discussed the question of how to sort 1 million 8-digit numbers in 1 megabyte of RAM. This reminded me of when I saw Obama in 2007 at Google - Eric Schmidt asked...
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Teardown of the mysterious KMS 4-port USB charger
In this article I tear down a 4-port USB charger of puzzling origin. This charger is a huge step above the $2 counterfeit chargers I examined earlier in design and manufacture, but considerably below...
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JavaScript on the go: Programming from your phone
Have you ever wanted to write a program when the only computer available is your phone? You can use an Android phone to write and run JavaScript programs by using a few simple tricks. While traveling...
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The 6502 overflow flag explained mathematically
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The 6502 CPU's overflow flag explained at the silicon level
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Notes on the PLA on the 8085 chip
The 8085 processor uses a PLA (programmable logic array) to control much of the activity within the processor, such as instruction decoding and controlling the data flow between components of the chip....
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Inside the ALU of the 8085 microprocessor
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Silicon reverse engineering: The 8085's undocumented flags
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View Article8085 instruction set: the octal table
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The 8085's register file reverse engineered
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Wealth distribution in the United States
Today's Forbes billionaires list inspired me to visualize the wealth inequality in the United States. Use the Forbes list and other sources, I've created a graph that shows wealth distribution in the...
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Tenma 72-7740 multimeter: review and teardown
The Tenma 72-7740 digital multimeter is a multimeter in the $70 price range. Overall, it's a nice, solidly-build meter and it has performed well for me. I received this DMM from Newark element14 for...
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Teardown and exploration of Apple's Magsafe connector
Have you ever wondered what's inside a Mac's Magsafe connector? What controls the light? How does the Mac know what kind of charger it is? This article looks inside the Magsafe connector and answers...
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The Mili universal car/wall USB charger, tested in the lab
I received a Mili universal USB charger for review from Mobile Fun. This interesting charger has some features that make it my current favorite travel charger. It runs off both wall power and car...
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Twelve tips for using the Rigol DS1052E Oscilloscope
In this article I share a few tips I've learned about using the Rigol DS1052E oscilloscope. The Rigol DS1052E digital oscilloscope. Push the knobs The knobs all have convenient actions if you push...
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Reverse-engineering the flag circuits in the 8085 processor
Processors all have status flags to keep track of conditions such as a zero value, a carry, or a negative value. Whenever you write a loop or conditional, these flags ultimately are in control. But how...
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Four Rigol oscilloscope hacks with Python
.gist { } .gist-data { height: 350px; } .gist-meta { font-size: 80% !important; } A Rigol oscilloscope has a USB output, allowing you to control it with a computer and and perform additional...
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Reverse-engineering the 8085's ALU and its hidden registers
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Simulating a TI calculator with crazy 11-bit opcodes
I've built a register-level simulator of a 1974 TI calculator chip that shows what actually happens inside a calculator when you perform operations and shows the calculator source code as it executes....
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