Application Note
9 of 19
002-27376 Rev. *A
2021-06-15
Getting Started with CXPI Transceiver S6BT112A
Software configuration
By controlling the NSLP pin, it is possible to transition between the three modes. To suppress the power
consumption of nodes that are constantly supplied with power, it is possible to transition to the power-saving
Sleep mode. In systems where power is supplied only when needed, you can choose not to use the
Wakeup/Sleep function.
Sleep mode is a power-saving mode in which each node stops sending and receiving data. All nodes transition
to Sleep mode after the power is turned on. Ensure that you turn on the power with NSLP = LOW. During Sleep
mode, the BUS signal is received without being decoded, and will be transmitted out from the RXD terminal at
the master node and from the CLK terminal at the slave node.
Standby mode is a transient mode during the transition from Sleep mode to Normal mode. During Standby
mode, transmission and reception output are suspended. When setting NSLP to HIGH, S6BT112A first
transitions to Standby mode. After the T
MODE_CHG
time, S6BT112A transitions to Normal mode automatically.
Normal mode is a mode in which communication is possible. During Normal mode, the transmission data,
which is input to the TXD terminal is encoded and output to the BUS line. The received BUS data is decoded
and output to the RXD terminal.
In addition to the operating modes, there are ThermalShutdown mode and WP_ThermalShutdown mode as
failsafe functions to prevent malfunctions at abnormally high device temperature. In Thermal Shutdown mode,
the clock or data from the MCU to the BUS will be stopped, but the decoded BUS signal can be monitored by
the output of the CLK terminal or RXD terminal. In WP_ThermalShutdown mode, the non-decoded BUS signal
can be monitored by the output of CLK terminal. When the temperature falls to the normal range, S6BT112A
transitions from WP_ThermalShutdown mode to Sleep mode.
4.1.2
Transition from Normal mode to Sleep mode
When the Sleep condition is met, the master node can transmit a Sleep frame.
The master node stops the clock output at T
clock_stop_m
time after receiving the Sleep frame. When the slave node
receives the Sleep frame, it prepares for Sleep and sleeps at T
sleep_s
time (see JASO D015-3 for T
clock_stop_m
time
and T
sleep_s
time).
S6BT112A transitions to Sleep mode by changing the NSLP pin from HIGH to LOW. Set the master node CLK pin
to HIGH in Sleep mode. Also, set the TXD pin to HIGH when not communicating according to the UART protocol.
The transition flow chart and timing chart from Normal mode to Sleep mode are shown in
respectively.
Figure 5
Transition flow from Normal mode to Sleep mode
