EEPROM with single pin interface

UNI/O bus timing example

Two years ago Microchip introduced serial EEPROMs with UNI/O. The speciality is the single pin data interface, so the memory chip needs only 3 pins including power. This can be great help for the smallest 6-pin microcontrollers like PIC10F or ATtiny10 series which doesn’t have any non-volatile memory writable from application itself. Memory densities range from 1 Kb to 16 Kb. It competes with 1-wire EEPROMs from Maxim but at significantly lower prices and lower working voltages.

UNI/O bus uses Manchester encoding to combine clock and data to single line. ACK bits at the end of each byte are similar to I2C bus, but there are always two: one from master and one from slave. Addressing and write protection is all managed by software. Currently there are no other UNI/O devices than EEPROMs but the bus manual suggest that there should be others like temperature sensors, A/D converters or port expanders. Application notes with code examples are available for several different MCUs.

$20 fuel injector tester

If you’re into DIY auto maintenance, here’s a project for you. Fuel injectors are made up of a coil of wire which opens a valve when energized, basically an electronic solenoid valve. These can wear out and to diagnose them properly requires more than just applying 12 volts and listening for a click.

Dino, a professional auto tech by day, shares his circuit for a fuel injector tester. Requiring a 555 timer, N-channel MOSFET and a handful of supporting components, the tester sends a pulse to the injector allowing you to separately measure fuel output with a pressure gauge.

Via Hack a Day.

Week in (p)review: January 16, 2011

By popular request we’re going to start the weekly review/preview posts again.

Last week was a big week for the Bus Blaster, but there was a lot of other stuff too:

This week will be busy too:

  • Bus Blaster v1 is being tested and will be available soon
  • The MCP2200 breakout board should be listed at Seeed this week too. Sjaak cut this one apart and put it back together, it’ll be fun
  • We’re into CPLDs, so look for a couple logic-replacement CPLD breakout designs and simple device tutorials. A CoolRunner-II board is nearly complete, we’ll also do a XC9500XL board. Look for a comparison of these Xilinx CPLDs later today
  • USB POV Toy, oh so hard to solder and program. Maybe someone will give you life this week
  • More Dangerous Protoboards from Sjaak
  • Will the Bus Pirate get an open source USB stack and move one step closer to production?
  • We made a USB backpack for the SparkFun color Nokia LCD knock-off. We tried to use it with the LCDs Seeed could find, but the driver is different. Now it’s kind of an orphan project. We’ll probably write up the design this week anyways
  • Less hacky stuff like advertising, site upgrades, and more are also in the works

What are you hacking this week? Our favorite project gets an SOIC protoboard.

Vsprog SWD working on STM8 and STM32VL embedded debugger

Serial Wire Debug is a new two-wire JTAG debugging protocol used by several low pin-count LPC and STM32 ARM chips. Adaptation of SWD by open source debuggers like OpenOCD has been slow.

Bingo succeeded in adapting the open source Versaloon firmware to do SWD programming on the cheap STM8S-Discovery and STM32VL-Discovery boards. Congratulations! We hope this is just the beginning of better SWD support in open source JTAG apps.

Via the contact form.

Real-Time audio spectrum analyser

Here’s an application using FFT on an PIC18F4550 8-bit microcontroller:

This project implements a real-time audio spectrum analyser using a PIC18F4550 8-bit microcontroller. The spectrum frequency analysis is performed by a highly optimised 16-bit Fast Fourier Transformation (FFT) routine coded entirely in C. The output from the FFT is displayed using a 128×64 graphical LCD to allow a real-time view of an audio signal.

Thanks sqkybeaver! Via the contact form.

Free PCB Sunday: Bus Pirate PIC programming adapter

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 we’re giving away two boards for the Bus Pirate PIC programming adapter. It provides a 13 volt source to put PIC 16F and 18F into programming mode. It is intended for the piratePICprog application, but it is still very much a work in progress. If you’d like a PCB just ask for one in the comments.

Now available to developers for $12 at Seeed Studio, read about the design on the wiki.

Continue reading “Free PCB Sunday: Bus Pirate PIC programming adapter”

Beginners guide to open source AVR dev tools

Interactive Matter has produced a detailed tutorial on developing software for the Atmel AVR with AVR-Eclipse, AVR-GCC & AVRDude. Designed for beginners, following these steps will result in the installation of a full fledged IDE, with code completion, one click building, no make files and buttons to flash the AVR.

Hacking toy RC cars

Project Lab provides the details on how to produce a wireless robotics platform using a cheap RC toy vehicle, Arduino, XBee and Processing. The vehicle is completely controlled by the code running on the remote computer which allows very rapid prototyping of the code to tell the vehicle what to do and how to react to the sensor events received from the vehicle. Complete Arduino and Processing code included.

App note: I2C controlled keypad scan IC

The TCS8418 is an I2C controlled keypad scan chip for up to 80 buttons:

• Operating Power-Supply Voltage Range of 1.65 V to 3.6 V
• Supports QWERTY Keypad Operation Plus GPIO Expansion
• 18 GPIOs Can Be Configured into Eight Inputs and Ten Outputs to Support an 8 × 10 Keypad Array (80 Buttons)
• 10 Byte FIFO to Store 10 Key Presses and Releases

TCS8418 in QFN and CSP (BGA) packages
TCA8418E in CSP (BGA) package

Thanks for the tip MichaelZ!


Xilinx free FPGA/CPLD design tutorials

The Arduino platform and bare microcontrollers are good ways to get started in developing embedded systems. But the way of the future is clearly CPLD and FPGA architecture. These devices are not simply a new type of chip, but a new and interesting design and development frontier. Their programs are developed using several methods, including schematic capture, and the Verilog and VHDL programming languages.

Each manufacturer has their own unique IDE for their chips, which is not open source. For example, if you have a Xilinx development board such as the Spartan-3A FPGA evaluation kit or the Coolrunner II CPLD board, then you would be using Xilinx’s free Webpack ISE design software.

Our soon to be released Bus Blaster v2 uses the Xilinx CoolRunner-II XC2C32A CPLD chip, as will some of our future offerings. Check out our CoolRunner-II CPLD quick start.

Xilinx has a number of free online training courses covering many aspects of FPGA circuit design and program development using their ISE software. A separate group of tutorials covers CPLD design. (Start with “Creating a New Design.”) Learning PLD development now will increase your use and development of future open source products.

Attiny2313 based LAN cable tester

Vasilis Stergiopoulos has built a RJ45 LAN cable tester. The circuit was originally designed to use a 555 and 4017 IC, but Vasilis has published the schematic and source code in assembly for using the Attiny2313 instead.

The Attiny2313 produces successive outputs at port D, where the LAN-cable is connected. If a straight cable is connected between connectors A and B, then the LEDs will glow in successive order. If a cross cable is connected, then the glow order will be as noted on the board, i.e. 1,2,7,4,5,8,3,6. If any other glow order occurs, it means that the cable is not wired correctly. If one or more LEDs don’t glow, then we have a corresponding open circuit. A remote unit with only the B connector (B2) can be used if both cable ends are not accessible in the same location.

Map proprietary connectors

Dan Reetz shows how to map proprietary connectors:

I love the Casio EX-FH100. I hate proprietary bullshit. It’s tremendously aggravating when a manufacturer arbitrarily makes up a new connector — especially when we have perfectly good standard connectors already. Proprietary bullshit stokes my rebel spirit, makes me fighty, makes me hack.

Via Makezine.

PLUNIFY: programmable logic design simplified

A new site allows you to conduct programmable logic design with Xilinx and Altera devices “in the cloud.” PLUNIFY, currently in Beta, allows you to experiment with PLD development in your web browser without downloading any software. A free account is available allowing you to 1 GB of storage space and free online development tools to create and simulate designs in Verilog and VHDL. Other features are available on a subscription basis such as online implementation and device matching.

Announcement: Open source PIC USB stack

Forum member Honken released an open source USB firmware for PIC microcontrollers. This is a major open source contribution, congratulations!

Most PIC 18F2550 and 18F4550 USB projects you see on the web use the Microchip USB source code. It’s easy to use and free. There’s one big problem: Microchip uses a license that isn’t open source compatible. Distributing the USB source with a project is against the rules.

Until now, we’ve relied on Microchip’s non-distributable driver in projects like the USB IR Toy and Logic Sniffer. We release our source code, but you have to download the USB driver from Microchip yourself. This is a pain, especially for beginners who aren’t familiar with compilers and build configurations.

Over the last few days we’ve tested the Honken USB firmware on several different PIC18F microcontrollers.  The latest version is available in SVN and the forum.

Our current goal is to get it running on the PIC 24FJ used in the Bus Pirate v4. We can begin volume manufacturing of the new Bus Pirate as soon as the driver is in place.  Can you help? Please join us in the forum.

Free SparkFun Free Day coupon code

Markus writes:

During yesterdays DDOS attack Free-day at SparkFun I was able to get through just one time during the two hours the event lasted. Therefore I managed to acquire 10$ (and got 2$ donated to charity).

Because I have no use for it, I thought I give it to you. It is worth 10$ and must be used before March 15, 2011. The code is:

2d1d13d5cd7b

Thanks Markus! Via the contact form.