TCAN1042 wake-up function

Jeffrey,

1. The TCAN1042-Q1 device is placed into Standby mode, which is a low power mode, by placing a logic high on the STB pin. Once in this state, the driver (TXD) is disabled, the CAN bus defaults to the common mode level, and the RXD is a low power monitoring mode. To wake the device from this state, a specific pattern needs to be sent to the bus (this pattern is detailed on pages 22 and 23 of the datasheet). Once the bus receives this correct pattern, the RXD pin outputs a logic low level pulse. This pulse is meant to be used to notify the microcontroller that a wake-up message has been received, the microcontroller sends a logic low to the STB pin, and the TCAN1042-Q1 is awakened.

2. In the method described in (1), the TCAN1042-Q1 responds to a wake-up request, but does not fully wake-up itself. The only way to fully wake-up the TCAN1042-Q1 itself is to manipulate and control the STB pin. With that in mind, you could have some sort of power supply (LDO, buck/boost converter) that responds to a low pulse to power up when the TCAN1042-Q1 RXD responds to a wake-up request, but this would be the same result as having a microcontroller wake the TCAN1042-Q1 up.

3. I'm not exactly sure what you are asking. If both the TCAN1042 and the MCU are in a low power state, yes, they will still work and respond to a wake-up request on the TCAN1042-Q1 bus.

Please let me know if you need any more clarification, or have anymore questions.

Regards,