Back in the October 2001 issue of Silicon Chip, we described an AVR ISP programmer with similar capabilities to those detailed here. The original design connects to your PC's parallel port, with just one low-cost IC providing buffering between the SPI interface and parallel port lines. The emphasis of the design was on ease of
construction and low cost.
This new design is slightly more complex but it provides a
number of useful additional features.
For a start, most PCs have a free serial port, whereas the
parallel port may already be used for a printer or scanner. Serial port interfaced devices are generally much more robust, too; there are no issues with inserting and removing the connector with power applied, and cable length is relatively unimportant.
Best of all, support for the AVR ISP Serial Programmer is
already built right into AVR Studio. This means that you can assemble, debug and then program your AVR micro, all within the same application. By contrast, the October 2001 design needs a separate application to perform the programming part of the cycle.
AVR Studio, by the way, is a complete set of PC-based development tools for use with Atmel's AVR microcontroller family. It includes a
project manager, source editor, assembler and simulator - and it's