TLE9263QX
High Speed CAN Transceiver
Rearming the Transceiver for Wake Capability
After a BUS wake-up event, the transceiver is woken. However, the CAN transceiver mode bits will still show wake
capable (=‘01’) so that the RXD signal will be pulled low. There are two possibilities how the CAN transceiver’s
wake capable mode is enabled again after a wake event:
•
The CAN transceiver mode must be toggled, i.e. switched from Wake Capable Mode to CAN Normal Mode,
CAN Receive Only Mode or CAN Off, before switching to CAN Wake Capable Mode again.
•
Rearming is done automatically when the SBC is changed to SBC Stop, SBC Sleep, or SBC Fail-Safe Mode
to ensure wake-up capability.
Note:It is not necessary to clear the CAN wake-up bit CAN_WU to become wake capable again. It is sufficient to
toggle the CAN mode.
Note:The CAN module is supplied by an internal voltage when in CAN Wake Capable Mode, i.e. the module must
not be supplied through the VCAN pin during this time. Before changing the CAN Mode to Normal Mode, the
supply of VCAN has to be activated first.
Wake-Up in SBC Stop and Normal Mode
In SBC Stop Mode, if a wake-up is detected, it is always signaled by the INT output and in the WK_STAT_1 SPI
register. It is also signaled by RXDCAN pulled to low. The same applies for the SBC Normal Mode. The
microcontroller should set the device from SBC Stop Mode to SBC Normal Mode, there is no automatic transition
to Normal Mode.
For functional safety reasons, the watchdog will be automatically enabled in SBC Stop Mode after a Bus wake
event in case it was disabled before (if bit WD_EN_ WK_BUS was configured to HIGH before).
Wake-Up in SBC Sleep Mode
Wake-up is possible via a CAN message (filter time t > tWake1). The wake-up automatically transfers the SBC into
the SBC Restart Mode and from there to Normal Mode the corresponding RXD pin in set to LOW. The
microcontroller is able to detect the low signal on RXD and to read the wake source out of the WK_STAT_1
register via SPI. No interrupt is generated when coming out of Sleep Mode. The microcontroller can now for
example switch the CAN transceiver into CAN Normal Mode via SPI to start communication.
Table 16
Action due to CAN Bus Wake-Up
SBC Mode after Wake
SBC Mode
VCC1
INT
RXD
LOW
LOW
LOW
LOW
LOW
Normal Mode
Stop Mode
Normal Mode
Stop Mode
ON
LOW
LOW
HIGH
HIGH
HIGH
ON
Sleep Mode
Restart Mode
Fail-Safe Mode
Restart Mode
Restart Mode
Restart Mode
Ramping Up
ON
Ramping up
Data Sheet
67
Rev. 1.1, 2014-09-26
INFINEON [ Infineon ]
