This kit permits one to directly interface either a Basic Stamp or a PIC with a parallel printer using 2400 baud serial data.
This permits the logging of alarms, temperature measurements, and hard copy data dumps directly to paper.
[Don't overlook the value of a printer in practicing the fine art of kludgemanship. I always found that a large part of my job was selling my design, even to my own management and even today, I can show my boss the most amazing design in the world, but if the only action is a scope trace, his eyes glaze over. But, show him the same design with a little chip driving an enormously clunky printer with tracter feed and I know that he knows it is an amazing design.
This is not to encourage engineers to be anything other than honest and certainly "kludgemanship" can be overdone; e.g., a design that performs an FFT with a few leads trailing off to a 20 foot motor generator. But, some of the most important lectures I had in college were those related to responsible kludgemanship.]
Old generic printers are available at ham and computer fests for the carrying away.
The kit ($10.00) consists of an 18-pin programmed 16C554, a 4.0 MHz ceramic oscillator, resistors, wire suitable for solderless breadboards and documentation. A PCB is not supplied.
An optional wire-wrap to DB25 female connector is available for $10.00 With a bit of manipulation, the wire-wrap terminals may be plugged into a solderless breadboard and a standard printer cable may be connected to the DB-25 side.
Eight of the PIC16C554 I/O terminals are used for DATA, one for /STROBE and one for INIT.
One is used for receiving the serial data from a Basic Stamp or PIC. Either TTL or EIA levels may be used.
One I/O terminal is used to indicate the unit is READY for a serial character.
The printer may be initialized by sending the character FE Hex. Upon receipt of this character, the printer's INIT lead is winked low so as to initialize the printer.
This feature may be defeated by grounding another I/O lead on the 16C554. The rationale is that you may desire to send graphical characters, including 0xFE and you really don't want the printer resetting.
Note that the design does not check to verify the printer is on-line, powered, there is paper and it is not busy. Rather, it assumes all is well, a character is received and it is sent blindly to the printer. However, printing is usually a monitored operation and a problem is obvious.
The kit includes examples of interfacing with a Basic Stamp, a PIC and a PC and this includes sample routines in Stamp Basic, PIC assembly and QBASIC, respectively.