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Section 20 Controller Area Network
Page 1008 of 2108 R01UH0134EJ0400 Rev. 4.00
Sep 24, 2014
SH7262 Group, SH7264 Group
way as the arbitration on the CAN Bus between two CAN nodes starting transmission at the same
time).
This bit can be modified only in Reset or Halt mode.
Bit 2: MCR2 Description
0 Transmission order determined by message identifier priority (Initial value)
1 Transmission order determined by mailbox number priority (Mailbox-31
Mailbox-1)
Bit 1—Halt Request (MCR1): Setting the MCR1 bit causes the CAN controller to complete its
current operation and then enter Halt mode (where it is cut off from the CAN bus). This module
remains in Halt Mode until the MCR1 is cleared. During the Halt mode, the CAN Interface does
not join the CAN bus activity and does not store messages or transmit messages. All the user
registers (including Mailbox contents and TEC/REC) remain unchanged with the exception of
IRR0 and GSR4 which are used to notify the halt status itself. If the CAN bus is in idle or
intermission state regardless of MCR6, this module will enter Halt Mode within one Bit Time. If
MCR6 is set, a halt request during Bus Off will be also processed within one Bit Time. Otherwise
the full Bus Off recovery sequence will be performed beforehand. Entering the Halt Mode can be
notified by IRR0 and GSR4.
If both MCR14 and MCR6 are set, MCR1 is automatically set as soon as this module enters
BusOff.
In the Halt mode, this module configuration can be modified with the exception of the Bit Timing
setting, as it does not join the bus activity. MCR[1] has to be cleared by writing a '0' in order to re-
join the CAN bus. After this bit has been cleared, this module waits until it detects 11 recessive
bits, and then joins the CAN bus.
Notes: 1. After issuing a Halt request the CPU is not allowed to set TXPR or TXCR or clear
MCR1 until the transition to Halt mode is completed (notified by IRR0 and GSR4).
After MCR1 is set this can be cleared only after entering Halt mode or through a reset
operation (SW or HW).
2. Transition into or recovery from HALT mode, is only possible if the BCR1 and BCR0
registers are configured to a proper Baud Rate.
Bit 1: MCR1 Description
0 Clear Halt request (Initial value)
1 Halt mode transition request