Archive Index (1999-2012) | 2013-current at | About releases open PC/104 I/O board design

May 30, 2001 — by LinuxDevices Staff — from the LinuxDevices Archive

Huntsville, AL — (news release) — has released a new free hardware design under the GNU general public license (GPL). The Grits board is a fully programmable I/O board for embedded processor systems based on the PC/104 bus standard. All of the source files have been released, including the CAD files for the schematic and board, manufacturing files for the printed circuit board, programming… files for the complex programmable logic device (CPLD), and the source code for the GNU/Linux driver code.

The concept of a fully programmable I/O board is that it ought to be possible to build one physical board design and to program the logic on the board to perform arbitrary I/O functions, so that one board design may serve multiple functions. The function of the board is then programmed in the VHDL language, and that is compiled and fitted to the CPLD on the board. The CPLD may be programmed in-circuit, and may be reprogrammed thousands of times. This allows the board to be very versatile. The initial VHDL design provided by is for a parallel I/O port which allows three I/O ports to address up to 1 million external addresses, and to receive and route external interrupts to the bus. However, the VHDL can be changed to perform bit wise control, arbitrary serial stream generation, or other less common I/O functions. is a web site dedicated to the cooperative development of free hardware designs, and the drivers for them. Free hardware design is the design and public release of the designs of useful electronic building blocks, in the forms of documentation, schematics, printed wiring board layouts, programmable logic implementations, and software drivers for them, as both source code and more immediately usable forms. These designs are not freeware, but rather copyrighted and licensed (under the GNU GPL) in such a way that they may be improved by other volunteers and potentially incorporated into other designs, under the same rules. The term copyleft is sometimes applied to this concept, where the licensing is designed specifically to keep the original design and any descendants which flow from it available to help the common good. For a more complete explanation of the concept and its implementation, see the Free Software Foundation web site.

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