BAT32G1x9 user manual | Chapter 22 CAN control
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Rev.1.02
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The state of the CAN sleep mode
The CAN module is in the following state after entering CAN sleep mode
-
The internal operating clock has stopped with minimal power consumption
-
The CAN acceptance pin (CRxD) of the detected falling edge function remains active to wake up the
CAN module from the CAN bus.
-
To wake up the CAN module from the CPU, data can be written to the PSMODE [1:0] of the CAN
Module Control Register (CnCTRL), but no other CAN module registers or bits can be written.
-
In addition to CnLIPT, CnRGPT, CnLOPT and CnTGPT, the other registers of the CAN module can
be read.
-
The CAN packet cache register cannot be written or read
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The MBON bit of the CAN0 Global Control Register (CnGMCTRL) is cleared.
-
Requests for transition to initialization mode were not Acknolwdgeed and were ignored.
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CAN sleep mode release
THE CAN sleep mode is released by the following events:
- When the CPU
writes
00B to the PSMODE [1:0] bit of the CnCTRL register
- The CAN receive pin (CRxD) detects the falling edge (i.e. the CAN bus level goes from recessive to dominant).
Note 1
Even if the falling edge appears in the SOF of the received message, it will not be received and stored.
If the CPU turns off the CAN clock while in CAN sleep mode. Even then, the CAN sleep mode will not
be released and the PSMODE [1:0] will continue to be 01B unless the clock for CAN is provided again.
In addition to this, received messages will not be received afterwards.
2. If the falling edge on the CAN receive pin (CRxD) is detected in the state where the CAN clock is
provided, the PSMODE0 bit needs to be cleared by software (for details, see
processing in
After the sleep mode is released, the CAN module returns to the operating mode when the CAN
sleep mode was requested, and the PSMODE [1:0] bit of the CnCTRL register is reset to 00B. If the
CAN sleep mode is released by a change in the STATE of the CAN bus, the CINTS5 bit of the
CnINTS register is set to 1, regardless of the CIE bit of the CnIE register. After the CAN module is
released from CAN sleep mode, it enters the CAN bus again by automatically detecting 11
consecutive recessive level bits on the CAN bus. The user application must wait until MBON=1
before accessing the packet buffer. When the CAN module is in CAN sleep mode, a transition
request to initialization mode is issued, and the request is ignored. Before entering initialization mode,
the CPU releases sleep mode through software
Note: Please note if the CAN sleep mode is released by the CAN bus event; Therefore, if a CAN bus event
occurs, a wake-up interrupt can occur even after the sleep mode is requested.
Note m= 0
to
15