NEC V850ES/F 3-L Series User Manual page 619

CAN Controller (CAN)
(2)
the operation modes, immediate transition to the CAN sleep mode is not
possible. In this case, the CAN sleep mode transition request has to be held
pending until the CAN bus state becomes bus idle (the 4th bit in the
interframe space is recessive). In the time from the CAN sleep mode
request to successful transition, the PSMODE[1:0] bits remain 00
the module has entered the CAN sleep mode, the PSMODE[1:0] bits are set
to 01 .
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• If a request for transition to the initialization mode and a request for
transition to the CAN sleep mode are made at the same time while the CAN
module is in one of the operation modes, the request for the initialization
mode is enabled. The CAN module enters the initialization mode at a
predetermined timing. At this time, the CAN sleep mode request is not held
pending and is ignored.
• Even when initialization mode and sleep mode are not requested
simultaneously (i.e the first request has not been granted while the second
request is made), the request for initialization has priority over the sleep
mode request. The sleep mode request is cancelled when the initialization
mode is requested. When a pending request for initialization mode is
present, a subsequent request for Sleep mode request is cancelled right at
the point in time where it was submitted.
Status in CAN sleep mode
The CAN module is in the following state after it enters the CAN sleep mode:
• The internal operating clock is stopped and the power consumption is
minimized.
• The function to detect the falling edge of the CAN reception pin (CRXDn)
remains in effect 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] bits of the CAN module control register (CnCTRL), but
nothing can be written to other CAN module registers or bits.
• The CAN module registers can be read, except for the CnLIPT, CnRGPT,
CnLOPT, and CnTGPT registers.
• The CAN message buffer registers cannot be written or read.
• MBON bit of the CAN Global Control register (CnGMCTRL) is cleared.
• A request for transition to the initialization mode is not acknowledged and is
ignored.
User's Manual U18743EE1V2UM00
Chapter 18
. When
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