SPRUJ53C April 2024 – February 2025 TMS320F28P550SG , TMS320F28P550SJ , TMS320F28P559SG-Q1 , TMS320F28P559SJ-Q1
The wakeup interrupt is used to allow the LIN module to automatically exit a low-power mode. A LIN wakeup is triggered when a low level is detected on the receive RX pin, and this clears the POWERDOWN bit.
In LIN mode, any node can terminate sleep mode by sending a wakeup signal, see Figure 29-26. A responder node that detects the bus in sleep mode, and with a wakeup request pending, sends a wakeup signal. The wakeup signal is a dominant value on the LIN bus for TWUSIG; this is at least 5 Tbits for the LIN bus baud rates. The wakeup signal is generated by sending a 0xF0 byte containing 5 dominant Tbits and 5 recessive Tbits.

Assuming a bus with no noise or loading effects, a write of 0xF0 to TD0 loads the transmitter to meet the wakeup signal timing requirement for TWUSIG. Then, setting the SCIGCR2.GENWU bit transmits the preloaded value in TD0 for a wakeup signal transmission.