TLE8262E Datasheet, PDF (12/93 Pages) Infineon Technologies AG – Universal System Basis Chip HERMES Rev. 1.0

TLE8262E
State Machine
4.2.4 SBC Normal Mode
SBC Normal Mode is used to transmit and receive CAN and LIN messages. In this mode, V_cc1µC is always “ON”
V_cc2 and V_cc3 can be turned-on or off by SPI command. In Normal Mode the watchdog needs to be triggered. It can
be configured via SPI, window watchdog and time-out watchdog is possible (default value is time-out 256 ms). All
the wake-up sources can be inhibited in this mode. The Limp Home output can be enabled or disabled via SPI
command. Via SPI command, the SBC can enter Sleep, Stop or Software Flash Mode. A reset is triggered by the
SBC when entering the Software Flash Mode. It is recommended to send at first SPI command the watchdog
setting. Please refer to Chapter 13.4.
4.2.5 SBC Sleep Mode
During SBC Sleep Mode, the lowest power consumption is achieved by having the main and external voltage
regulators switched-off. As the microcontroller is not supplied, the integrated Watchdog is disabled in Sleep Mode.
The last Watchdog configuration is not stored. The CAN and LIN modules are in their respective Wake-capable
or OFF modes and the Limp Home output is unchanged, as before entering the Sleep Mode. If a wake-up appears
in this mode, the SBC goes into Restart Mode automatically. In Sleep Mode, not all wake-up sources should be
inhibited, this is required to not program the device in a mode where it can not wake up. If all wake sources are
inhibited when sending the SBC to Sleep Mode, the SBC does not go to Sleep Mode, the microcontroller is
informed via the INT output, and the SPI bit “Fail SPI” is set. The first SPI output data when going to SBC Normal
Mode will always indicate the wake up source, as well as the SBC Sleep Mode to indicate where the device comes
from and why it left the state.
Note: Do not change the transceiver settings in the same SPI command that sends the SBC to Sleep Mode.
4.2.6 SBC Stop Mode
The Stop Mode is used as low power mode where the µC is supplied. In this mode the voltage regulator V_cc1µC
remains active. The other voltage regulator (V_cc2/3) can be switched on or off.
The watchdog can be used or switched off. If the watchdog is used the settings made in Normal Mode are also
valid in Stop Mode and can not be changed.
The CAN and LIN modules are not active. They can be selected to be off or used as wake-up source. If all wake
up sources are disabled, (CAN, LIN, WK, cyclic wake) the watchdog can not be disabled, the SBC stays in Normal
Mode and the watchdog continues with the old settings.
If a wake-up event occurs the INT pin is set to low. The µC can react on the interrupt and set the device into Normal
Mode via SPI. There is no automatic transition to SBC Normal Mode.
There are 4 Options for SBC Stop Mode
• WD on (the watchdog needs to be served as in Normal Mode
• WD off (special sequence required see Chapter 11.2.4)
• Cyclic Wake up with acknowledge (interrupt is sent after set time and needs to be acknowledged by SPI read)
• Cyclic Wake-up, Watchdog off (interrupt is sent after set time)
Cyclic Wake-Up Feature
SBC Stop Mode supports the cyclic wake-up feature. By default, the function is OFF. It is possible to activate the
cyclic wake-up via “Cyclic WK on/off” SPI bit. This feature is useful to monitor battery voltage, for example, during
parking of the vehicle or for tracking RF data coming via the RF receiver. The Cyclic Wake-up feature sends an
interrupt via the pin INT to the µC after the set time. The cyclic wake-up feature shares the same clock as the
Watchdog. The time base set in the SPI for the Watchdog will be used for the cyclic wake-up. The timer has to be
set before activating the function. With the cyclic wake-up feature the watchdog is not working as known from the
other modes. In the case that both functions (Watchdog and cyclic wake-up) are selected, the cyclic wake-up is
activated and each interrupt has to be acknowledged by reading the SPI Wake register before the next Cyclic
Wake-Up comes. Otherwise, the SBC goes to SBC Restart Mode.
Data Sheet
12
Rev. 1.0, 2009-03-31