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Category Archives: Projects

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Fine-Grained Timing

SysTick interrupts are typically configured to occur on a 1ms boundary, but in some cases, due to clocking or power constraints, they can range from 5-20ms. If the interrupt is used merely for task scheduling, or for coarse grained delays, then the resolution is acceptable. However, sometimes finer resolution is called for. Fine Grained Blocking For example, after asserting the chip […]

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PEGMA Test0: Blinking LEDs

The PEGMA boards and parts arrived this week. I was able to successfully populate the board, compile a test project and debug it using the STLINKV2 debugger from STMicro. Here are the bullets: Microcontroller: STMicro STM32F205VC (Originally planned on VG, 1MB flash is overkill) Buck Regulator: TPS62240 Stepping down 5Vusb to 3.3V for both V0 […]

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PEGMA Rev0 Schematic

This week I sent the first revision of the PEGMA board off to Advanced Circuits for manufacture. The final features onboard are as follows: 5 input boost power supplies (1.4V – 6V, 1.5A) 3 output boost power supplies (5V – 14V, 1.5A) 8 peripheral buck power supplies (1.8V – 5.5V, 500mA) Domain 0: Microcontroller only (STM32F205VG), […]

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Biasing An Adjustable SMPS

The PEGMA project uses two types of adjustable switched mode power supplies (SMPS) in multiple configurations. The LM2623 is a boost SMPS; five are used as input power supplies and three are used for peripherals. The TPS62240 is a buck SMPS; one provides power to the STM32F205VG microcontroller and therefore needs to be adjusted between 1.8v […]

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Demultiplexers, Decoders and Addressable Latches

Recently I ran into a problem while working on the PEGMA project and the solution took me a long time to solve. I thought I would take this opportunity to do a bit of 74 series logic review. Let’s say for instance that you had a situation where you wanted to select / de-select some […]

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PEGMA Project

My PhD research involves the intelligent allocation of energy to peripherals in low power or energy harvested embedded systems. To that end, I have been designing the PEGMA (Peripheral Energy Generation Measurement and Allocation) board. This board will ultimately enable accurate monitoring and control of both the power generation and consumption of its own peripherals […]

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PHP Debugging in Eclipse

The next milestone of the chart project will require some analysis and manipulation of data sets. Seeing as how I am new to PHP, my intuition tells me that the better part of judgment is not to fly blindly into it … Unfortunately, setting up Eclipse to debug PHP code in a reasonable manner is […]

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Chart Project

I have been working behind the scenes on the site quite a bit recently. First, I established version control using SVN to a server in house. SVN helps to naturally break up large tasks into smaller chunks which is just the kind of help we need here. Next, I established Eclipse with PDT as my […]

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