TLE9263QX
High Speed CAN Transceiver
10.2.1
CAN OFF Mode
The CAN OFF Mode is the default mode after power-up of the SBC. It is available in all SBC Modes and is intended
to completely stop CAN activities or when CAN communication is not needed. The CANH/L bus interface acts as
a high impedance input with a very small leakage current. In CAN OFF Mode, a wake-up event on the bus will be
ignored.
10.2.2
CAN Normal Mode
The CAN Transceiver is enabled via SPI in SBC Normal Mode. CAN Normal Mode is designed for normal data
transmission/reception within the HS-CAN network. The Mode is available in SBC Normal Mode and in SBC Stop
Mode. The bus biasing is set to VCAN/2.
Transmission
The signal from the microcontroller is applied to the TXDCAN input of the SBC. The bus driver switches the
CANH/L output stages to transfer this input signal to the CAN bus lines.
Enabling sequence
The CAN transceiver requires an enabling time tCAN,EN before a message can be sent on the bus. This means that
the TXDCAN signal can only be pulled LOW after the enabling time. If this is not ensured, then the TXDCAN needs
to be set back to HIGH (=recessive) until the enabling time is completed.
Only the next dominant bit will be transmitted on the bus.
Figure 28 shows different scenarios and explanations for CAN enabling.
V
TXDCAN
t
CAN
Mode
t CAN,EN
tCAN,EN
t CAN,EN
CAN
NORMAL
CAN
OFF
t
t
V
CANDIFF
Dominant
Recessive
recessive TXD level
required bevor start of
transmission
Correct sequence ,
Bus is enabled after tCAN, EN
t
CAN, EN not ensured , no
transmission on bus
tCAN, EN not ensured ,
no transmission on bus
recessive TXD
level required
Figure 28 CAN Transceiver Enabling Sequence
Reduced Electromagnetic Emission
To reduce electromagnetic emissions (EME), the bus driver controls CANH/L slopes symmetrically.
Reception
Analog CAN bus signals are converted into digital signals at RXD via the differential input receiver.
Data Sheet
65
Rev. 1.1, 2014-09-26
INFINEON [ Infineon ]
