M16C29 Datasheet, PDF (325/499 Pages) Renesas Technology Corp – RENESAS MCU M16C FAMILY / M16C/Tiny SERIES

M16C/29 Group
17. CAN Module
17.2.2 CAN Operating Mode
The CAN operating mode is activated by setting the Reset bit in the C0CTLR register to 0. If the Reset bit
is set to 0, check that the State_Reset bit in the C0STR register is set to 0.
If 11 consecutive recessive bits are detected after entering the CAN operating mode, the module initiates
the following functions:
• The module's communication functions are released and it becomes an active node on the network
and may transmit and receive CAN messages.
• Release the internal fault confinement logic including receive and transmit error counters. The
module may leave the CAN operating mode depending on the error counts.
Within the CAN operating mode, the module may be in three different sub modes, depending on which
type of communication functions are performed:
• Module idle : The modules receive and transmit sections are inactive.
• Module receives : The module receives a CAN message sent by another node.
• Module transmits : The module transmits a CAN message. The module may receive its own
message simultaneously when the LoopBack bit in the C0CTLR register = 1
(Loop back mode enabled).
Figure 17.18 shows sub modes of the CAN operating mode.
Start
transmission
Module idle
TrmState = 0
RecState = 0
Finish
transmission
Finish
reception
Detect
an SOF
Module transmits
TrmState = 1
RecState = 0
Module receives
TrmState = 0
RecState = 1
Lost in arbitration
TrmState, RecState: Bits in the C0STR register
Figure 17.18 Sub Modes of CAN Operating Mode
17.2.3 CAN Sleep Mode
The CAN sleep mode is activated by setting the Sleep bit in the C0CTLR register to 1. It should never be
activated from the CAN operating mode but only via the CAN reset/initialization mode.
Entering the CAN sleep mode instantly stops the clock supply to the module and thereby reduces power
dissipation.
Rev. 1.12 Mar.30, 2007 ^{page 301} of 458
REJ09B0101-0112