Donut Board

Donut USB Interface Development 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 theGNU 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 theMC68HC908JB8 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.zip04-15-2005, 53k
CAD source files - GNU/Linux	gz of Eagle 4.13 files	donut.tar.gz04-15-2005. 49k
Assembly source files	zip of firmware source code	donutasm.zip 05-11-2005, 26k
Object files	zip of firmware object code	donutobj.zip04-15-2005, 0k
Manufacturing	zip of Gerber/Excellon/text	donutmfg.zip04-15-2005, 122k
Designer's notes	html	donutnote.htm 05-11-2005, 12k

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.zip04-15-2005, 53k

CAD source files - GNU/Linux

gz of Eagle 4.13 files

donut.tar.gz04-15-2005. 49k

Assembly source files

zip of firmware source code

donutasm.zip 05-11-2005, 26k

Object files

zip of firmware object code

donutobj.zip04-15-2005, 0k

Manufacturing

zip of Gerber/Excellon/text

donutmfg.zip04-15-2005, 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

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