The Maxim DS2431 1K EEPROM is 1-Wire device that adds storage to a project using a single microcontroller pin. We previously interfaced a 1-wire thermometer, but this EEPROM is slightly different because it draws power directly from the 1-Wire bus. Grab the datasheet (PDF) and follow along while we read and write this simple 1-Wire memory.
Complex programmable logic devices (CPLDs) contain the building blocks for hundreds of 7400-serries logic ICs. Complete circuits can be designed on a PC and then uploaded to a CPLD for instant implementation. A microcontroller connected to a CPLD is like a microcontroller paired with a reprogrammable circuit board and a fully stocked electronics store.
At first we weren’t sure of the wide appeal and application of CPLDs in hobbyist projects, but we’ve been convinced. A custom logic device can eliminate days of reading datasheets, finding the ideal logic IC combination, and then waiting for chips to arrive. Circuit boards are simpler with CPLDs because a single chip with programmable pin placement can replace 100s of individual logic ICs. Circuit mistakes can be corrected by uploading a new design, rather than etching and stuffing a new circuit board. CPLDs are fast, with reaction times starting at 100MHz. Despite their extreme versatility, CPLDs are a mature technology with chips starting at $1.
We’ve got a home-etchable, self programming development board to get you started. Don’t worry, this board has a serial port interface for working with the CPLD, and doesn’t require a separate (usually parallel port) JTAG programmer.
Continue reading “How-to: Programmable Logic Devices (CPLD)”
Download: buspirate.v0d.zip
Dallas/Maxim’s 1-Wire protocol is the most requested addition to the Bus Pirate. We finally got some 1-Wire parts, and today we’ll demonstrate the DS1822 1-Wire digital thermometer. Grab the datasheet (PDF) and follow along.
This post is accompanied by release v.0d of the Bus Pirate firmware for hardware version 0. This includes the new 1-Wire protocol library, more configuration options, and other improvements.
Continue reading “Parts: 1-Wire Temperature Sensor (DS1822)”
Download: buspirate.v0c.zip
A few weeks ago we wrote about our Bus Pirate universal serial interface tool. We used the recent holiday to add some new features, like a JTAG programmer, macros, frequency measurement, and more. A major code reorganization makes everything easier to read and update.
Check out the a demonstration of the new features below. We’re compiling a roadmap and wish list, so share your ideas in the comments. You can also see how we used the Bus Pirate to read a smart card and test-drive an I2C crystal oscillator.
Continue reading “Bus Pirate Firmware Update (v.0c), JTAG And More”
The DS1077 is a 5volt, 133MHz to 16kHz programmable clock source. The internal frequency divider is configured over a simple I2C interface, and the chip requires no external parts. Not bad for under $2. We used the Bus Pirate to test this chip before using it in a project. Grab the datasheet (PDF) and follow along. Continue reading “Parts: 133MHz-16.2kHz Programmable Oscillator (DS1077)”
Our wallets are filling up with SIM and RFID cards that contain hidden information. Using our latest project, the Bus Pirate universal serial interface, we can dump the memory from many common smart cards. In today’s How-to, we show you how to interface common smart cards, and walk you through the data stored on a FedEx Kinko’s prepaid value card.
Continue reading “How-to: Read A FedEx Kinko’s Smart Card (SLE4442)”
UPDATE: New firmware with JTAG and more
We’re always excited to get a new chip or SIM card to interface, but our enthusiasm is often dampened by the prototyping process. Interfacing any chip usually means breadboarding a circuit, writing code, and hauling out the programmer; maybe even a prototyping PCB.
A few years ago we built the first ‘Bus Pirate’, a universal bus interface that talks to most chips from a PC serial terminal. Several standard serial protocols are supported at 3.3-5volts, including I2C, SPI, and asynchronous serial. Additional ‘raw’ 2- and 3- wire libraries can interface almost any proprietary serial protocols. Since this has been such a useful tool for us, we cleaned up the code, documented the design, and released it here with specs, schematic, and source code.
Continue reading “How-to: The Bus Pirate, Universal Serial Interface”
