NEC V850E/RS1 User Manual page 643

(c) No transmission request is pending
If any one of the conditions mentioned above is not met, the CAN module will operate as follows.
• If the CAN sleep mode is requested from the initialization mode, the CAN sleep mode transition
• If the CAN bus state is not bus idle (i.e., the CAN bus state is either transmitting or receiving)
• If a request for transition to the initialization mode and a request for transition to the CAN sleep
• If a CAN sleep mode request is pending waiting for the CAN bus state to become bus idle while
• If the CAN sleep mode transition request is made while a initialization mode transition request is
Even when the initialization mode and sleep mode are not requested simultaneously (i.ethe first
request was not granted when a second request was made), the request for initialization has prior-
ity over the CAN sleep mode request. The CAN sleep mode request is cancelled when the initiali-
zation mode is requested. When a pending request for the initialization mode is present, a
subsequent request for the CAN sleep mode request is cancelled right at the point in time when it
was submitted.
(2) Status in CAN sleep mode
• The CAN module is in one of the following states 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
• To wake up the CAN module from the CPU, data can be written to PSMODE[1:0] of the CAN
• The CAN module registers can be read, except for CnLIPT, CnRGPT, CnLOPT, and CnTGPT.
• The CAN message buffer registers cannot be written or read.
• A request for transition to the initialization mode is not acknowledged and is ignored.
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Chapter 16 FCAN Controller
request is ignored and the CAN module remains in the initialization mode.
when the CAN sleep mode is requested in one of 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 00B. When the module has entered the CAN sleep mode,
PSMODE[1:0] are set to 01B.
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.
the CAN module is in one of the operation modes, and if a request for transition to the
initialization mode is made, the pending CAN sleep mode request becomes disabled, and only
the initialization mode request is enabled (in this case, the CAN sleep mode request continues
to be held pending).
held pending waiting for completion of communication in one of the operation modes, the CAN
sleep mode transition request is ignored and only the initialization mode transition request
remains valid (in this case, the CAN sleep mode request continues to be held pending).
wake up the CAN module from the CAN bus.
module control register (CnCTRL), but nothing can be written to other CAN module registers or
bits.
User's Manual U16702EE3V2UD00 643