BeagleBone CANBus Cape
System Reference Manual
Revision A1
Page 17 of 21
side is connected to UART port of AM335X; these signals are required to be at 3.3V
voltage level.
The CANBus Cape provides an option to install a terminal resistor for CAN bus signals.
The CAN High and CAN Low signals are connected to pin 7 and pin 2 of D-Sub
connector J1. The ground signal for CAN is isolated and connected to pin 3 of J1. Figure
4 shows the transceiver circuit on the CANBus Cape.
Figure 4. CAN Transceiver Circuit
5.3
Isolated Power and Ground
The CANBus Cape uses an isolated DC-DC converter RSZ-3.305HP to convert 3.3V to
5.0V for the CAN transceiver. RSZ-3.305HP features a transformer driver, an isolation
transformer, a rectifier network as well as a linear regulator. The supply and ground leads
on the input and output sides are isolated. This isolation prevents noise currents from
entering local ground and damage sensitive circuitry.
5.4
Controller Signals
The controller side of the ISO1050 is connected to UART1 port of AM335X, which can
also be pin-muxed as DCAN1. A noise filter is applied between the transceiver and the
controller.
