SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
Entering Power Down mode is controlled via the input clock stop request signal (mcanss_clkstp_clkstop_req) or MCAN_CCCR[4] CSR bit. As long as the clock stop request signal is active, the MCAN_CCCR[4] CSR bit is read as 1. When all pending transmission requests have completed, the MCAN module waits until bus idle state is detected. Then the MCAN module sets the MCAN_CCCR[1] INIT to 1 to prevent any further CAN transfers. The MCAN module acknowledges that it is ready for power down by setting the output clock stop acknowledge signal (mcanss_clkstop_clkstop_ack) to 1 and the MCAN_CCCR[3] CSA bit to 1. In this state, before the clocks are switched off, further register accesses can be made. A write access to the MCAN_CCCR[1] INIT bit will have no effect. Now the module clock inputs MCAN_ICLK and MCAN_FCLK may be switched off.
To leave power down mode, the application has to turn on the module clocks before resetting the input clock stop request signal respectively the MCAN_CCCR[4] CSR flag bit. The MCAN will acknowledge this by resetting the output clock stop acknowledge signal respectively the MCAN_CCCR[3] CSA flag bit. Afterwards, the application can restart CAN communication by resetting MCAN_CCCR[1] INIT bit.