Author Archives: the machinegeek

Chip note: MCP7941X I2C RTCC with EEPROM, SRAM, Unique ID and Battery Switchover

Microchip’s MCP79411 general purpose I2C™Compatible real-time clock/calendar (RTCC) is highly integrated with nonvolatile memory and advanced features including a battery switchover circuit for backup power, a timestamp to log power failures and digital trimming for accuracy. It can use a low-cost 32.768 kHz crystal or other clock source and the chip operates over a supply […]

Xilinx CPLD applications handbook

This document from Xilinx could easily be titled “Everything You Always Wanted to Know About Xilinx CPLDs But Didn’t Know Where to Look.” Its the Xilinx CPLD Applications Handbook, featuring the CoolRunner-II and XC9500XL. It’s a 422 page compendium of application notes, hardware interfacing tips and specs that any Xilinx CPLD user will want to […]

Serial EEPROM bitbang Launchpad interface

Rob from the 43oh blog has posted his method to interface a 24LC32A serial EEPROM interface to the Launchpad. The 24LC32A is a 32Kb PROM with a 2 wire serial interface or I2C compatible, and since it can be clocked @400kHz @3.6V bit banging seemed like it would be easy. External pull up should be […]

Short notice: AVR Studio 5 webinar

Atmel is presenting a free webinar on March 17, 2011 on AVR Studio 5. This one hour presentation will begin at 8:00 AM PDT and will cover the Visual Assist Solution Explorer project manager, the AVR Software Framework for AVR XMEGA and AVR UC3 and more including many example projects. You can download your copy […]

555 based FPGA/CPLD debugging oscillator

Randomgarfield from fromorbit posted the above video, depicting his use of a 555 timer as a small oscillator tο clock CPLDs whіƖе debugging a small state machine. I needed a variable slow speed clock to help me debug a design I’m creating with a bunch of CPLDs. Given the current focus on the venerable 555 […]

Control an LED with brainwaves and Arduino

Sean the Flex Guy has posted his basic experiments capturing brainwave data from the Neurosky Mindset BCI and conveying it to an Arduino. The readings are processed by the Arduino and displayed on an LED, in this case indicating the relative attention level of the participant. Sean has published the ActionScript 3.0 API he created […]

Trends: microcontrollers outsource interrupt handling

In this article, Chris Edwards highlights the reasons behind moving interrupt handling from the main microcontroller onto to low power companion chips. In order to conserve electricity and processor power, the growing practice is to have the bulk of the microcontroller powered down most of the time, only waking up for brief periods for necessary […]

Trivia: CPLD on a PDIP?

Atmel produces what are believed to be the only CPLD devices sold in PDIP form: the ATF2500C and ATF750C . These devices are priced at between $5 and $8 at Digikey and Mouser. Programming hardware and software is available from Atmel. Atmel provides free design software known as WinCUPL, which mainly supports programming in the […]

Vienna hackerspace autoposts realtime project videos

It seems like every hackerspace has their own means of communicating status messages to their members. The hackers at MetaLab in Vienna have put together a rather novel way of letting the world know they have completed a project. While some hackerspaces simply notify their members that they are open for business, they take things […]

PyMite: Python-on-a-chip

Python-on-a-Chip (p14p) is a project to develop a reduced Python virtual machine (codenamed PyMite) that runs a significant subset of the Python language on microcontrollers without an OS. The other parts of p14p are the device drivers, high-level libraries and other tools. They’ve released ports for the Microchip PIC/24dcPIC, Teensy 2.0, Arduino Mega and others. […]

App note: Intro to digital communications systems

Digital modulation techniques are seeing increasing use worldwide. In the US, the FCC is actually mandating narrowband digital mobile radio (DMR) for certain Land Mobile Radio (LMR) users as explained in this Digital Mobile Radio Association white paper. Datasheets for various chips increasingly made reference to acronyms like GMSK, FSK and others. Agilent has published […]

Radio spectrum dashboard

The FCC has a unique and authoritative reference known as the Radio Spectrum Dashboard. It provides a public means of reviewing how spectrum bands are allocated and for what uses, and who holds licenses and in what areas. This version provides basic, plain language information about frequencies generally deemed appropriate for mobile broadband (225 MHz […]