SLLSFE8B November 2024 – November 2025 TCAN2845-Q1 , TCAN2847-Q1
PRODUCTION DATA
During debug or development this pin can be used to disable the watchdog actions. When the pin is active, the device expects normal WD triggers, but ignores any mode changes or actions outside of setting the watchdog failure interrupt flag and incrementing and decrementing the watchdog counter. When the pin is released, the flags self-clears, and the watchdog counter either goes back to default or programmed value. The pin is default active high but can be configured active low by using register 8'h0E[0] = 0b.
When the device is in sleep or fail-safe mode, this pin can be used as a digital wake up pin by enabling this feature using register 8'h0E[1] = 1b and 8'h0E[2] = 1b. When the device wakes up due to a SW pin state change, SWPIN interrupt at 8'h51[1] is set. If VCC1 is present in sleep mode, the thresholds are based on VCC1 levels. If VCC1 is not present, the levels are based off an internal voltage rail, VIHSWINT and VILSWINT. This pin can then be used to wake up when an external CAN FD or LIN transceiver is wake capable or MCU to wake up the device. This can be accomplished in several ways. If the external transceiver has an inhibit pin, external circuitry can be used to provide a wake input to this pin. The processor can connect directly to this pin and initiate the wake up without using a SPI command.
Figure 8-18 provides a state diagram on how the SW pin behaves.