The TCAN1162x-Q1 implements a low-power wake receiver in the standby and sleep mode that uses the multiple filtered dominant wake-up pattern (WUP) defined in the ISO11898-2:2016 standard.

The wake-up pattern (WUP) consists of a filtered dominant bus, then a filtered recessive bus time followed by a second filtered bus time. The first filtered dominant initiates the WUP and the bus monitor is now waiting on a filtered recessive, other bus traffic do not reset the bus monitor. Once a filtered recessive is received, the bus monitor is now waiting on a filtered dominant. The other bus traffic do not reset the bus monitor. Immediately upon receiving of the second filtered dominant, the bus monitor recognizes the WUP and drives the RXD terminal low, if a valid V_IO is present signaling to the controller the wake-up request. If a valid V_IO is not present when the wake-up pattern is received the device drives the RXD output pin low once V_IO > UV_IOR.

The WUP consists of:

• A filtered dominant bus of at least t_{WK_FILTER} followed by
• A filtered recessive bus time of at least t_{WK_FILTER} followed by
• A second filtered dominant bus time of at least t_{WK_FILTER}

For a dominant or recessive to be considered “filtered”, the bus must be in that state for more than t_{WK_FILTER} time. Due to variability in the t_{WK_FILTER} the following scenarios are applicable. Bus state times less than t_{WK_FILTER(MIN)} are never detected as part of a WUP, and thus no wake request is generated. Bus state times between t_{WK_FILTER(MIN)} and t_{WK_FILTER(MAX)} may be detected as part of a WUP, and a wake request may be generated. Bus state times more than t_{WK_FILTER(MAX)} are always detected as part of a WUP, and thus a wake request is generated. See Figure 10-7 for the timing diagram of the WUP.

The pattern and t_{WK_FILTER} time used for the WUP and wake request prevents noise and bus stuck dominant faults from causing false wake requests while allowing any CAN or CAN FD message to initiate a wake request.

ISO11898-2:2016 has two sets of times for a short and long wake-up filter times. The t_{WK_FILTER} timing for the TCAN1162x-Q1 has been picked to be within the min and max values of both filter ranges. This timing has been chosen such that a single bit time at 500 kbps, or two back to back bit times at 1 Mbps triggers the filter in either bus state.

For an additional layer of robustness and to prevent false wake-ups, the device implements the t_{WK_TIMEOUT} timer. For a remote wake-up event to successfully occur, the entire wake-up pattern must be received within the timeout value. If a the full wake-up pattern is notreceived before the t_{WK_TIMEOUT} expires, then the internal logic is reset and the device remains in sleep mode without waking up. The full pattern must then be transmitted again within the t_{WK_TIMEOUT} window. See Figure 10-7.

*The RXD pin is only driven once V_IO is present.

Figure 10-7 Wake-Up Pattern (WUP) From Sleep Mode To Standby Mode