T WR- 9 S 1 2 G 1 2 8 J U N E 2 , 2 0 1 0
U S E R G U I D E
14
NOTE: CAN Port Connector – Molex 39-30-3045
Mates with; Housing – Molex 39-01-4040, Pin – Molex 39-00-0217
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. Figure 11 below details the option header
shunt positions.
Figure 11: CAN Termination Enable
Standby Mode
The CAN PHY is configured for normal mode by default. To enable standby (STB) mode,
apply a high logic level at test point TP1. Refer to the TJA1040T Reference Manual for use
and capabilities of the Standby Mode.
USER PERIPHERALS
User I/O includes 1 potentiometer, 4 push button switches, and 4 green LEDs for user I/O.
The USER (JP14) option header enables or disables each User I/O function individually. The
sections below provide details on user I/O. Figure 12 below shows the USER jumper settings.
Potentiometer
The TWR-S12G128 target board applies a single-turn, 5K, ohm potentiometer (POT) to
simulate analog input. The POT is connected to an ATD input on the target MCU and is
decoupled to minimize noise transients during adjustment. Figure 12 below shows the USER
jumper settings.
