This application use case shows MCU (microcontroller) to communication bus transceiver with bi-directional wake-up from the MCU side or the communication bus side.

Figure 2-1 example shows MCU to communication bus transceiver with bi-directional wake-up. When both the MCU and bus communication are idle and return both INC and IND to HIGH, the isolator transitions to STANDBY state and turns off the high-speed data channels after the STANDBY state enable delay time, t_{LP_EN}. When the MCU wants to communicates, the MCU pulls INC LOW (nCS) and the isolator wakes-up, turns on the high-speed channels and pulls OUTC LOW waking up the SPI to Bus Transceiver device preparing for communication with other nodes of the network. The SPI to Bus Transceiver uses the input from OUTC as a wake-up request to prepare for the high-speed communication. Similarly, if the system is in low-power mode and the communication bus issues a wake-up request, the SPI to Bus Transceiver processes the request and pulls IND (nWAKE) LOW. The isolator wakes-up, and turns on the high-speed channels and asserts OUTD LOW. The MCU uses an interrupt IO or equivalent on OUTD to wake-up and prepare for the high-speed communication.