SLLSFE8B November 2024 – November 2025 TCAN2845-Q1 , TCAN2847-Q1
PRODUCTION DATA
The device automatically enters standby mode from restart mode. Upon initial power up, this transition happens when VCC1 > UVCC1 and tRSTN_act time has expired. VCC2 is turned on at power up but is not required to by greater than UVCC2 to transition to standby mode. The device can enter standby mode by writing a 00b to register 8'h0B[7:6] from normal mode. The watchdog function is default on in standby mode. Standby mode only supports timeout watchdog and automatically changes to this when entered. When WD_STBY_DIS, register 8'h14[0] = 0b (default value) entrance to standby mode has a long timeout window, tINITWD, that a WD trigger event must take place when entered from restart mode. The watchdog can be disabled for standby mode by setting 8'h14[0] = 1b. In standby mode, the transceiver can be programmed to meet the applications requirements. There are several blocks that are active in this mode. In standby mode, the CAN FD transceiver can be configured as listen, wake capable or off. The LIN transceiver can be configured as listen, wake capable or off. If programmed as wake capable, the low power CAN and LIN receivers are actively monitoring the bus for the wake up pattern (WUP). The WAKEx pins monitor is active. The SPI is active so that the microprocessor can read and write registers in the memory for status and configuration. The device goes from sleep mode to restart mode to standby mode automatically upon a bus WUP event, WUF (if selective wake is enabled), or a local wake up from the WAKEx pins and when VCC1 > UVCC1R. If VCC1 is disabled, the device enters standby mode after tRSTN_act timer times out.
Upon entering standby mode, the SWE timer (if enabled), tINACTIVE, starts and any SPI command from the processor clears the SWE timer. This feature makes sure the node is in the lowest power mode if the processor does not come up properly. To enable this feature register 8'h1C[7] (SWE_EN) must be set to 1b.
The following provides the description on how selective wake interacts between sleep and standby modes.