SH7137 Datasheet, PDF (766/1160 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperH™ RISC engine Family

Section 19 Controller Area Network (RCAN-ET)
Bit 5 — Sleep Mode (MCR5): Enables or disables Sleep mode transition. If this bit is set, while
RCAN-ET is in halt mode, the transition to sleep mode is enabled. Setting MCR5 is allowed after
entering Halt mode. The two Error Counters (REC, TEC) will remain the same during Sleep
mode. This mode will be exited in two ways:
1. by writing a '0' to this bit position.
2. or, if MCR[7] is enabled, after detecting a dominant bit on the CAN bus.
If Auto wake up mode is disabled, RCAN-ET will ignore all CAN bus activities until the sleep
mode is terminated. When leaving this mode the RCAN-ET will synchronise to the CAN bus (by
checking for 11 recessive bits) before joining CAN Bus activity. This means that, when the No.2
method is used, RCAN-ET will miss the first message to receive. CAN transceivers stand-by
mode will also be unable to cope with the first message when exiting stand by mode, and the S/W
needs to be designed in this manner.
In sleep mode only the following registers can be accessed: MCR, GSR, IRR and IMR.
Important: RCAN-ET is required to be in Halt mode before requesting to enter in Sleep mode.
That allows the CPU to clear all pending interrupts before entering sleep mode. Once all interrupts
are cleared RCAN-ET must leave the Halt mode and enter Sleep mode simultaneously (by writing
MCR[5]=1 and MCR[1]=0 at the same time).
Bit 5 : MCR5
0
1
Description
RCAN-ET sleep mode released (Initial value)
Transition to RCAN-ET sleep mode enabled
Bit 4 — Reserved. The written value should always be '0' and the returned value is '0'.
Bit 3 — Reserved. The written value should always be '0' and the returned value is '0'.
Bit 2 — Message Transmission Priority (MCR2): MCR2 selects the order of transmission for
pending transmit data. If this bit is set, pending transmit data are sent in order of the bit position in
the Transmission Pending Register (TXPR). The order of transmission starts from Mailbox-15 as
the highest priority, and then down to Mailbox-1 (if those mailboxes are configured for
transmission).
Rev. 2.00 Sep. 10, 2008 Page 740 of 1130
REJ09B0402-0200