GoodThopter10
The GoodThopter10 is a sexy GoodFET CAN device based around the design of the GoodFET31. Unlike the general- purpose GoodFET boards, the purpose of this board is to be used in the exploration of Automotive communication buses, currently supporting only the CAN bus. In addition to GF31 circuitry we have added a high-speed CAN Transceiver (MCP2551) and a Stand-alone CAN Controller with a SPI Interface (MCP2515).
CAD Files
Eagle CAD 6.x files for the design can be found in /branches/goodthopter10 of the GoodFET subversion repository, or along with gerbers as goodthopter10.zip.
Bill of Materials
Resistor values can be approximated.
N.B., The BOM including Digi-Key part numbers can be found in SVN /branches/goodthopter10/bom
| Quantity | Package | |
| 1 | SSOP28 | FT232RL |
| 1 | TSSOP38 | MSP430F2274 |
| 1 | TSSOP20 | MCP2515 |
| 1 | SOIC8 | MCP2551 |
| 1 | HC49/UP** | 20MHz SMD Crystal, 15pF |
| 4 | 0603 | 0.1μF Decoupling Capacitors |
| 2 | 0603 | 15pF Capacitors* |
| 5 | 0603 | 0603 LED |
| 4 | 0603 | 330R LED Series Resistors |
| 1 | 0603 | 10K Pull-up Resistor |
| 1 | USB Type B | |
| 1 | D-SUB 9 Position Mountable Conn. - 1734351-1 |
* These should match the required capacitance of the crystal.
** The /US SMD package works as an alternative.
Construction
Place the components as shown in the comments of this Flickr image. As this is a surface-mount design, be sure that you are familiar with such techniques or have assistance before beginning assembly.
See the GoodFET Tutorial for more detailed explanations.
Usage
Build and flash firmware with the following commands. This board self-flashes over USB through a masked-ROM bootloader, so there is no need for an external programmer.
export board=goodthopter10 make clean install goodfet.can info
See the GoodFET Tutorial for more detailed explanations.
Errata
OBD2 Cable
TODO: Fix this broken image.
The pinout of the GoodThopter1x series is above and since CANH and CANL is located on pins 7 and 2 (respectively) the cable you will want to choose is something like this one and not the Sparkfun model which has a different pinout for CANH,CANL. Apologies, I think in the future, if it makes sense we will design to the cheaper option after we test both.
MCP2551 Voltage
The worst errata is the MCP2551 needs operating voltage between 4.5-5.5V. Right now it is connected to a 3.3V bus.
TODO: Replace this broken image.
The remaining layout issues don't seem to affect performance, but a board cleanup is suggested for the GoodThopter11.