Cornbread TM Programmable IO Board

CornbreadTM – Fully programmable ISA bus I/O Board, using surface mount parts. The Cornbread design is based on the Lattice ispLSI2096A-80LQ128 CPLD, in a 128 pin Plastic Quad Flat Pack (PQFP). There is only one integrated circuit on the board. The Cornbread design is very versatile, and allows many ways to utilize it for I/O functions. In order to minimize costs, this board is built on a two-sided board (i.e. no power or ground plane layers) with 10 mil lines and spaces.

The GNU/Linux version, designed with Eagle 4.01, is updated to utilize the additional features of Eagle. In this version, all of the bypass capacitors are on top of the board. Copper pours were used to improve the signal integrity. Once again, this board is a 2 layer board to minimize cost. The same CPLD design is used in both versions.

Cornbread Board

Contents File type File name
Specification Adobe Acrobat version 3 cornbred.pdf 04-28-00, 193k
Specification html cornspec.htm
Schematics zip of HPGL plotter files 04-28-00, 178k
CAD source files – DOS/Wxx zip of Tango Schematic 1.50, Tango PCB Plus 2.30 files 03-28-00, 44k
CAD source files – GNU/Linux gzipped tar file of Eagle 4.01 files cornbred.tar.gz 05-25-01. 175k
CPLD source files zip of VHDL, pin, configuration files 04-15-00, 10k
CPLD programming files zip of JEDEC file 04-15-00, 9k
Manufacturing zip of Gerber/Excellon/text 03-28-00, 140k
GNU/Linux Drivers user space driver (c code) cb_user.tgz
Wxx 16-bit Drivers Zips of C code – test program – basic IO example

NOTE: to unpack the Eagle file in Linux, make a cornbred directory, copy the cornbred.tar.gz file into it, and then invoke tar xvcf cornbred.tar.gz

This will unpack the entire set of CAD and manufacturing files in the cornbred directory.

Hardware designer: Diehl Martin

Note: The source code for all designs shown here is released under the GNU General Public License.