FreeIO.org - Donut Board

The Donut Board works. For the latest status, look here: donutnote.htm

The first of the promised USB development boards has been released. The Donut Board is designed to be an easily expandable board on which to breadboard USB interfaces, in order to ease the development of USB-based devices. The Donut board is based on the Freescale (formerly Motorola) MC68HC908JB8 microcontroller, which has an integrated USB interface, and into which custom built firmware can be downloaded in order to customize the USB interface to user needs. GNU/Linux-based software to control the USB interface from the PC end of the USB link is also under development, based on the great articles by Greg Kroah-Hartman, published during 2004 in Linux Journal.

This project is currently under rapid development. The CAD files are available below. All files are released under the GNU General Public License. This board was developed using Eagle 4.13, running on GNU/Linux.

Firmware development is being accomplished with freely available tools from P&E Microcomputer Systems. Because the MC68HC908JB8 has internal monitor firmware, and user firmware resides in internal flash memory, the Donut Board has a port which allows the MC68HC908JB8 to be remotely programmed and debugged from a PC, using the MON08 Multilink cable from P&E.

board pix

Figure 1. Donut Board mounted in a Pac-Tec case. Large version of this picture here.

bare board pix

Figure 2. Front side of bare Donut Board pcb. Bare boards arrived 26 April 2005.
Large version of this picture is here.

bare board rear pix

Figure 3. Back side of bare Donut Board pcb. Large version of this picture is here.

donut board cad image

Figure 4. This is the CAD drawing for the Donut USB Transceiver Test Board. The right 2/3 of the board is available for breadboarding.

Contents	File type	File name
Specification	pdf file	donut.pdf
Schematic	png file of schematic	donutpix2.png 04-05-2005, 269k
PCB layout, large	png file of PCB	donutpix1.png 04-15-2005, 128k
CAD source files - DOS/Wxx	zip of Eagle 4.13 files	donut.zip 04-15-2005, 53k
CAD source files - GNU/Linux	gz of Eagle 4.13 files	donut.tar.gz 04-15-2005. 49k
Assembly source files	zip of firmware source code	donutasm.zip 05-11-2005, 26k
Object files	zip of firmware object code	donutobj.zip 04-15-2005, 0k
Manufacturing	zip of Gerber/Excellon/text	donutmfg.zip 04-15-2005, 122k
Designer's notes	html	donutnote.htm 05-11-2005, 12k

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

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

Hardware designer: Diehl Martin - freeio@hiwaay.net.

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

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