Hardware Overview
We came up with the design of having 5 boards sitting on a CAN bus talking to each other. To make the control easier we decided it would be a good idea to allow data to be transfered to and from a laptop that could be sitting in the kart. This laptop communicates over a usb CDC-serial link.
This shows a rough drawing of the kart and where each PCB is located. It also shows where the power enters the system from the battery into the brake board. This is important as the power is passed to the other boards over the Ethernet cables along side CAN_H and CAN_L.
These are nodes that sit on the CAN bus and control various parts of the kart. Currently there will be at least three boards, one for each of the acceleration, breaking and steering controls.
Each board consists of a SAM7x and the required other circuitry. A note about these chips, they are no longer produced, but we are using them as they are the only Atmel chip that have both the USB and CAN Bus functionality we want
##Mistakes in original design
The pinout for the LS8073 quadrature clock converter used on the steering board is incorrect and the following pins need to be swapped. PIN 8 and PIN 5 are in each others place and PIN 7 and PIN 6 are in each others place. This was fixed in the Altium schematic.
No ground pin on the USART connectors. This was worked around by using them as UART and pulling the SCK low to make a ground pin. This was also done in trace.h
ADVREFF has a cap (C8) between it and V_3.3. I suspect was a mistake and should have been a de-coupling capacitor. To fix this C8 should be removed and replaced with a 0 ohm resistor. Currently this has only been fixed on the brake board.