It was an interface that launched a thousand hacks. Near trivial to program, enough I/O lines for useful work, and sufficiently fast for a multitude of applications: homebrew logic analyzers, chip programmers, LCD interfaces and LED light shows, to name a few.
Today the parallel printer port is on the brink of extinction (and good riddance, some would say). Largely rendered obsolete by USB, few (if any) new peripherals even include a parallel connector, and today’s shrinking computers — nettops, netbooks, media center PCs — wouldn’t have space for it anyway. That’s great for tidy desks, but not so…
Introduction to FTDI bitbang mode
Parts: 4×20 VFD character display (NA204SD02)
Futaba makes vacuum florescent character displays that can be used as a drop-in replacement for common character LCDs. VFDs have a wider viewing angle, and generally look cooler.
Futaba’s character displays can be interfaced using the standard 8-bit or 4-bit parallel LCD interface, or a simple two-wire protocol. The protocol type is set by resistors on the back of the display, so it’s not particularly easy to change without a hot-air rework station. Today we’ll demonstrate a serially-interfaced VFD using the Bus Pirate.
Futuba VFD character LCD replacement (NA204SD02, $7.00). Datasheet (PDF).
VFD (pin #)
Bus Pirate
GND (1)…
Mixed voltage interfacing with the Bus Pirate
Most of the parts we use operate at 3.3volts, but we still run into a lot of old 5volt stuff, and an occasional 2.5volt or 1.8volt part. This post explains how to use the Bus Pirate’s open collector pin mode to interface with parts at different voltages.
We’ve got more details and some example scenarios below the break. Yup, this is another Bus Pirate post. It’ll all be over soon though, because there’s a few days left to get your own Bus Pirate for $30, fully assembled and shipped worldwide.
Overview
The Bus Pirate has a normal pin mode…
Parts: SPI EEPROM (25AA/25LC)
Microchip’s 25AA/25LC EEPROMs are data storage chips with a simple 3-wire interface. The 25AA/LC is an SPI version of the common 24AA/LC I2C EEPROM. It comes in capacities of 128bytes to 128kilobytes. We looked at the smallest, the 128byte 25AA010A.
There are Bus Pirate demonstrations for most types of serial EEPROMs. Check out our previous 1-wire (DS2431) and I2C (24LC1025) EEPROM posts.
Continue below to see our test circuit and a demonstration of the 25AA010 EEPROM. We used the Bus Pirate to play with this chip from our PC. For a limited time you can get your own Bus…
Parts: ShiftBrite RGB LED module (A6281)
Macetech’s ShiftBrite is a high-power RGB LED coupled with an Allegro A6281 backpack. The A6281 uses three 10bit pulse-width modulators to mix millions of colors using the red, green, and blue elements in the RGB LED. Multiple modules can be chained together for bigger projects, like the ShiftBrite table.
Below the break we demonstrate a ShiftBrite module using the Bus Pirate. For a limited time you can get your own Bus Pirate, fully assembled and shipped worldwide, for only $30.
ShiftBrite RGB LED module (Macetech, $4.99). ShiftBrite datasheet and example code, Allegro A6281 datasheet (PDF).
The ShiftBrite module is…
Parts: I2C real-time clock calendar (PCF8563)
The PCF8563 is a real-time clock/calendar/alarm chip with an I2C interface. This would be useful in projects where the primary microcontroller doesn’t have enough resources for an interrupt driven clock.
We demonstrate the PCF8563 using the Bus Pirate after the break. For a limited time you can get your own Bus Pirate, fully assembled and shipped worldwide, for only $30.
PCF8563 real-time clock calendar (Octopart search, $1.33). Datasheet (PDF).
The schematic above shows a bare-bones circuit for the PCF8563. It requires a simple external oscillator circuit with a 32.768khz watch crystal (Q1). The oscillator input pin needs an external…