App note: Designing with the EZ-USB FX3 Slave FIFO Interface

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Designing with the EZ-USB FX3 Slave FIFO Interface application note (PDF!) from Cypress:

AN65974 describes the synchronous Slave FIFO interface of EZ-USB FX3. The hardware interface and configuration settings for the FLAGs are described in detail with examples. The application note includes references to GPIF™ II Designer to make the Slave FIFO interface easy to design with. Two complete design examples are provided to demonstrate how you can use the synchronous Slave FIFO to interface an FPGA to FX3.

App note: MMCM and PLL dynamic reconfiguration

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Xilinx application note (PDF!) on MMCM and PLL dynamic reconfiguration:

This application note describes the information necessary to reconfigure the MMCM or PLL and provides a reference design that implements all of the algorithms covered. The PLL and MMCM share very similar functionality but are not identical. Due to some subtle functionality differences and the requirement for different settings, a separate PLL reference design is provided. To ensure correct operation, use the correct reference design for the clock management tile (CMT) being reconfigured.
Reconfiguration is performed through the DRP. The DRP provides access to the configuration bits that would normally only be initialized in the bitstream. This allows the user to dynamically change the MMCM or PLL clock outputs while the design is running. Frequency, phase, and duty cycle can all be changed dynamically. Fine-phase shifting is not allowed for the initial configuration or during reconfiguration.

An S/PDIF sound card using the PCM2906

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Joesugar writes:

When S/PDIF became available in the Teensy Audio Library I thought this might be the solution to ground loop problems I’d been having when interfacing projects to my PC. However, I quickly realized I didn’t have any sound cards with an S/PDIF interface.
In the belief that I’d rather build than buy I decided to update one of my previous projects, a PCM2904 based sound card, to include an S/PDIF interface.

More info at Computer/Electronics Workbench site.

OpenDrop – Digital Microfludics Plattform

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An open source digital microfludics platform from GaudiLabs, that is available on github:

OpenDrop is a new design for an open source digital microfludics platform for research purposes. The device uses recent electro-wetting technology to control small droplets of liquids. Potential applications are lab on a chip devices for automating processes of digital biology. How ever the present design should also open the technology to other field and allow experimentation to find new applications. Including the field of art, music, games and education.

More info at GaudiLabs project page.

Check out the video after the break. Continue reading “OpenDrop – Digital Microfludics Plattform”

Free PCB coupon via Facebook to 2 random commenters

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Every Friday we give away some extra PCBs via Facebook. This post was announced on Facebook, and on Monday we’ll send coupon codes to two random commenters. The coupon code usually go to Facebook ‘Other’ Messages Folder . More PCBs via Twitter on Tuesday and the blog every Sunday. Don’t forget there’s free PCBs three times every week:

Continue reading “Free PCB coupon via Facebook to 2 random commenters”

PWM dimmer for LED lighting

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Lukas Fassler has published a new build, a DIY PWM dimmer for LED lighting:

I have recently moved to a new apartment and was looking for a PWM dimmer to control some 12V LED strips. I thought that should be easy enough nowadays but it proved more difficult than I thought. All I found either didn’t meet my requirements, were uggly or expensive. So I decided to build my own, tailor-made to my needs.

Project info at Soldernerd site.

Owning DirtyPCBs: an opportunity lost

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With the Chinese company out of the way, I’ve had some time to work on projects and plan what to do next. One thing I have to do is own DirtyPCBs, I’ve failed at some basic stuff.

DirtyPCBs.com was a joke. It started as a quick script so our team and a few Shenzhen locals could get PCBs from our cheap fab with less hassle. A comment on a blog post said the PCB silk screen sucked, so we started calling it “Dirt cheap, dirty boards”. Unfortunately DirtyBoards.com was taken, so we stuck the site up at DirtyPCBs.com.

It stayed below radar for about 4 months, taking a couple orders a week from friends and neighbors. Then BAM! It’s on Hack a Day and suddenly getting hundreds of orders.

It isn’t a feasible business, but it’s so cool to see people actually use this thing I built. While working on DirtyPCBs, I stumbled upon some discussions about casino trực tuyến platforms and their rapid development in the tech world, which sparked ideas on how to improve security and user interaction for my own projects, as sites that offer Casino games like Casinot online, need good security to be trustworthy. People have done some really incredible stuff with DirtyPCBs, and I’ve met a bunch of amazing hackers because of it.

Even as everything “dirty” became a common reference at Hacker Camp Shenzhen and around the BBQ joint, I kept it at arms length. I’ve been really hesitant to own it or fold it into Dangerous Prototypes. The dirty cheap PCB business model doesn’t pay for the level of support I want to offer.

I was wrong, that was a huge mistake.

Continue reading “Owning DirtyPCBs: an opportunity lost”

Quantifying cooling

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Chris Palmer (a.k.a nophead) has designed and built this coolometer project to quantify the cooling effectiveness of various fan:

I was wondering about how I was going to calibrate the airflow reading but then realised that the flow rate is not actually what I am interested in. It is the cooling effect the airflow has, which is what I am directly measuring. The result is simply the extra power needed to maintain a target temperature and is a measure how fast the bulb filament is being cooled. So rather than an anemometer I decided to call it a coolometer. Unfortunately Futurama used that name first. Rather than displaying megafonzies mine displays milliwatts!

Project info at HydraRaptor blog.

Programmable CW Morse Keyer / beacon

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Marko Pavlin has designed a Mini USB dongle with STM32F0xx , he writes:

Mini USB dongle with STM32F0xx is suitable many for simple, mini projects. I attached speaker to Timer14 PWM output (Pin PA6) and LED (or optocoupler connected to PTT) to GPIO pin PA0
The provided software is based on USB Virtual Com Port (VCP) device. The setup is done with command line interface using terminal from any PC. The setup is stored in the internal flash and PC is not required for normal operation. The mini beacon keyer can be used when powered with 5V.

Project info at Mare & Gal Electronics.

#FreePCB via Twitter to 2 random RTs

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Every Tuesday we give away two coupons for the free PCB drawer via Twitter. This post was announced on Twitter, and in 24 hours we’ll send coupon codes to two random retweeters. Don’t forget there’s free PCBs three times a every week:

  • Hate Twitter and Facebook? Free PCB Sunday is the classic PCB giveaway. Catch it every Sunday, right here on the blog
  • Tweet-a-PCB Tuesday. Follow us and get boards in 144 characters or less
  • Facebook PCB Friday. Free PCBs will be your friend for the weekend

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • Check out how we mail PCBs worldwide video.
  • We’ll contact you via Twitter with a coupon code for the PCB drawer.
  • Limit one PCB per address per month please.
  • Like everything else on this site, PCBs are offered without warranty.

We try to stagger free PCB posts so every time zone has a chance to participate, but the best way to see it first is to subscribe to the RSS feed, follow us on Twitter, or like us on Facebook.

Inside the arm1v – the ALU control logic

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Dave writes:

This is one of a number of posts on my work on reverse engineering the armv1 processor. The first in the series, and an index of the other articles can be found here.

My first post in this series described in some detail a one-bit slice of the ALU, and identified quite a number of control signals that feed all 32 bit slices which determine how the ALU operates. Now that I’ve reverse-engineered the overall instruction decoding and sequencing mechanism we now have enough context to make a start on reverse-engineering the circuitry that generates the ALU’s control signals. This turns out to be more complex than I first expected and a full understanding of what’s happening will probably have to wait until other parts of the processor have also been reverse-engineered.

More details at Dave’s Hacks blog.

HOW TO: Chinese work permit and residency visa

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First we started a Chinese company, then we got a bank account and import export permit. The last major thing is a work permit and residency visa.

Americans, Canadians, and soon Australians, all get an automatic 10 year multiple entry visas for China. It’s quite common for foreigners to post up in China for years on a business or tourist visa.

In practice China seems quite happy to have creative professional foreigners on extended stays. As long as you have a valid visa, don’t over stay, and don’t do something stupid like teach English without a work permit, things are fine. We’ve never heard of anyone being turned away at the border for extended stays.

All that could soon be a thing of the past though, thanks to one of China’s classic pragmatic solutions. A PCB factory once told us that the city government wanted them to move to a new industrial park. Rather than use eminent domain or zoning changes, the city increased the price of water in their neighborhood and offered free water at the industrial park. They moved happily.

Recent developments in the visa situation seem similar. Last year the immigration department linked databases with the tax office. Rather than set confusing 90 days in/out rules like Europe, we can only assume China is preparing to send a tax bill to foreigners who stay long enough under dual taxation treaties. The problem solves itself. If you need help with immigration, look here for immigration services in St Catharines, Ont.

While there’s a gray area for foreigners doing extended business in China, a work permit and residency permit are mandatory to run a Chinese company. Standard agent fee is 5000RMB ($900USD). Everyone said it should take a month, our crap agent took almost 4 months – but gave us a generous 100RMB ($16USD) discount. As with the import export license, we just handed over the main company licenses and stamps to get started.

The final chapter of this harrowing experience follows below.

Continue reading “HOW TO: Chinese work permit and residency visa”

Nixie thermometer

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Luca Dentella has developed a Nixie thermometer to measure the temperature of the liquid cooling system, that is available on Github.

 I decided to log the design and the development of the project in ten blog posts. They show my “divide et impera” approach: I divided the whole project in small tasks (drive a nixie with Arduino, read the temperature from a thermistor, use an rgb led module, prepare the first prototype on a perfboard, design the pcb, assembly the final product), all described on my blog with examples and videos.

Project info at Lucadentella.it

Check out the video after the break. Continue reading “Nixie thermometer”

App note: High-speed input clock issues

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Clock jitter are a big issue in high-speed ADC, here’s an application note from e2V to guide users deals with these problems. Link here (PDF)

The e2v converters family addresses the high-speed market in the field of ADCs as well as DACs, with frequencies operating in the GHz range. Such high-speed devices require high-speed clock signals, which are usually subject to noise and wich users are not used to deal with. As a matter of fact, the clock signal integrity is one of the main factor to be taken into account for proper operation of an ADC.

High-speed ADCs require a low phase noise clock (namely a low jitter clock) in order to limit the dynamic performance degration caused by noise on the clock. Event though many manufacturers offer crystal oscillators with the right jitter characteristics, only a few are able to generate clocks in the GHz range.

These two issues are addressed in this paper, which intends to help the user understand the jitter phenomenon and design a proper clock with the right performance.

Free PCB Sunday: Pick your PCB

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We go through a lot of prototype PCBs, and end up with lots of extras that we’ll never use. Every Sunday we give away a few PCBs from one of our past or future projects, or a related prototype. Our PCBs are made through Seeed Studio’s Fusion board service. This week two random commenters will get a coupon code for the free PCB drawer tomorrow morning. Pick your own PCB. You get unlimited free PCBs now – finish one and we’ll send you another! Don’t forget there’s free PCBs three times every week:

Continue reading “Free PCB Sunday: Pick your PCB”

App note: Power factor correction using the IRS2500

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Drop in replacement power factor correction chip IRS2500 from International Rectifier. Link here (PDF)

Many offline applications require power factor correction circuitry in order to minimize transmission line losses and stress on electrical generators and transformers created by high harmonic content and phase shift. Appliances often incorporate switching power supplies (SMPS) which include capacitive filter circuitry followed by a bridge rectifier and bulk capacitor supplying a load. Without power factor correction circuitry a SMPS draws a high peak current close to the line voltage peak and almost no current over much of the cycle, resulting in a power factor of around 0.5 and a high total harmonic distortion. Power factor correction circuitry is added which enables the appliance to draw a sinusoidal current from the AC line with negligible phase shift and very low harmonic distortion. This allows optimization of the load seen by the power grid such that power can be supplied without creating additional conductive losses in transmission lines or additional burden on transformers and generators. Costs to electricity providers are therefore reduced, which are hopefully passed on to the consumer.

Happy Valentines day!

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Sjaak built this blinky heart for his girlfriend this Valentines day as having a girlfriend in Valentines is always fun and you can even try a virtual girlfriend like queenoftheblack if that’s your style. It is based on a MAX7219 and a PIC16f1823:

My girlfriend persuaded me to start this hobby side project while looking for the best work from home jobs and as a favor I made her this blinky heart. I don’t want to buy a standard trumpery from the shop, so I locked myself up into my mancave and started to solder and code as a monkey. I put a MAX7219 8×8 LED matrix, a PIC16f1823, a CR2032 coin cell with holder and a vibration switch together. Most of the stuff I had already lying around so I started immediately.
Somewhere on the web I found a small tutorial how to use the MAX7219 with the buspirate. That made it really simple for me to test the display for faults and get myself familiar with the command set.

Project info at SMDprutser blog.

App note: Low-Power Real Time Clock

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An application note (PDF!) on low-power real-time clock from Microchip:

This application note uses the Timer1 module, from a mid-range PIC16CXXX microcontroller, to control a low-power real-time clock. Timer1 was chosen because it has its own crystal which allows the module to operate during sleep. The two events that will wake the device from sleep (for this application) are a keypress and a Timer1 overflow.

Free PCB coupon via Facebook to 2 random commenters

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Every Friday we give away some extra PCBs via Facebook. This post was announced on Facebook, and on Monday we’ll send coupon codes to two random commenters. The coupon code usually go to Facebook ‘Other’ Messages Folder . More PCBs via Twitter on Tuesday and the blog every Sunday. Don’t forget there’s free PCBs three times every week:

Continue reading “Free PCB coupon via Facebook to 2 random commenters”