SLLSFE8B November 2024 – November 2025 TCAN2845-Q1 , TCAN2847-Q1
PRODUCTION DATA
The sleep wake error (SWE) timer (tINACTIVE) is a timer used to determine if specific functions are not working or if communication between the device and processor is present. This feature is disabled by default. The SWE timer can be enabled by setting SWE_EN; 8'h1C[7] = 1b. See Figure 8-42 for information on which modes the SWE timer start in and when. When enabled, at power up with VCC1_CFG = 10b for SBC mode control, if the device has not had the PWRON flag cleared or been placed into normal mode, the device enters sleep mode when tINACTIVE times out. If VREG_CONFIG1 register 8'h0D[7:6], VCC1_CFG, has been set to 01b for always on and the SWE timer times out while the device is in normal or standby modes, the device transitions to restart mode.
The device wakes up if the CAN or LIN bus provides a WUP or a local wake event takes place thus entering standby mode. Once in standby mode, the tSILENCE and tINACTIVE timers start. If the tINACTIVE expires the device re-enter sleep mode. When the device receives a CANINT, LWU or FRAME_OVF such that the device leaves sleep mode, entering restart mode and then enters standby mode, the processor has the programmed SWE timer time to clear the flags or place the device into normal mode. If this does not happen, the device enters either restart mode or sleep mode depending upon the programmed value of VCC1_CFG. When in standby or normal mode and the CANSLNT flag persists for tINACTIVE, the device enters sleep mode. Examples of events are the processor is no longer working and not able to exercise the SPI bus. A go to sleep command comes in, and the processor is not able to receive or respond to the command. See Figure 8-43 .
The restart timer can be either tRSTTO or tINACTIVE (SWE timer), and is selected using register 8'h4F[0], RSTRT_TMR_SEL. The SWE timer is default disabled and must be enabled if tINACTIVE is to be used.