Freescale Semiconductor Demonstration Board for Freescale MC9S12XHY256 Microcontroller DEMO9S12XHY256 DEMO9S12XHY256 用户手册
产品代码
DEMO9S12XHY256
D E M O 9 S 1 2 X H Y 2 5 6
J U L Y 1 5 , 2 0 1 0
U S E R G U I D E
15
Differential input CAN signals, for both CAN channels, are terminated with 120 ohms. Option
headers, JP13 and JP15 allow the user to optionally disconnect signal termination. Avalanche
diodes protect the CAN PHY from voltage surges on the input differential signal lines. Figure
13 below shows the CAN connector pin-out.
headers, JP13 and JP15 allow the user to optionally disconnect signal termination. Avalanche
diodes protect the CAN PHY from voltage surges on the input differential signal lines. Figure
13 below shows the CAN connector pin-out.
Figure 13: CAN_PORT
J7
C
A
NL_
0
CANH
_
0
CANL
_
1
CANH
_
1
4
3
2
1
Front View
–
Looking into
Connector
NOTE: CAN Port Connector
– Molex 39-30-3045
Mates with; Housing
– Molex 39-01-4040, Pin – Molex 39-00-0036
CAN Termination Enable
CAN bus termination of 120 ohm with virtual ground is applied to the differential CAN signals
on both channels. The SPLIT output from each PHY is connected to the virtual ground
providing common-mode stabilization. The differential CAN bus signal termination may be
removed using option header JP13 or JP15. To prevent signal corruption, both option jumpers
must be installed or both option jumpers must be removed. The CAN bus should not be
operated with only 1 signal termination applied.
on both channels. The SPLIT output from each PHY is connected to the virtual ground
providing common-mode stabilization. The differential CAN bus signal termination may be
removed using option header JP13 or JP15. To prevent signal corruption, both option jumpers
must be installed or both option jumpers must be removed. The CAN bus should not be
operated with only 1 signal termination applied.
NOTE:
To prevent signal corruption both shunts should be either ON or OFF
Figure 14: CAN Termination Enable
2
Connects CANL termination
4
Connects CANH termination
JP13
NOTE: JP13 applies termination to CAN0 while JP15 applies termination to CAN1. JP15 is
similar to JP13.