Phytec phyCORE-PXA255, Hardware Manual

Page: 63 / 106

CAN Interface

PHYTEC Meßtechnik GmbH 2004 L-657e_0
55
11 CAN Interface
An industry-standard CAN interface is populated on the PXA255
Development Board for integration into networked machines and
systems. The CAN controller is located on the phyCORE module.
Ethernet
2 * USB
Host
USB
Client
Power
Socket
AC97
IN
MIC
OUT
Expansion Board
FF-UART BT-UART
Touch Connect
LCD
Touch Panel
RESET
Button
CAN
Figure 29: CAN Connector
The signals CAN-RxD and CAN-TxD are optically isolated from the
phyCORE module over an ADU1402 opto-coupler (U45) and are
converted over an 82C251 CAN transceiver (U46) to CANH and
CANL. A switching voltage regulator converts the exernal CAN
supply voltage in a range from 8-24V to a 5V/0.5A CANVCC. This
enables galvanic separation of the CAN circuitry from the potential of
the Development Board. Jumpers JP7 and JP10 must be closed at
position 2+3 in order to support galvanic separation, when closed at
position 1+2 the CAN interface is powered by the internal 5 V supply
from the Development Board.