Renesas M32R/ECU Series, User Manual

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32180 Group User’s Manual (Rev.1.0)
CAN MODULE
Synchronization
Segment
Propagation Segment Phase Segment1 Phase Segment2
(1) (2) (3)
Sampling Point
• This diagram shows the bit timing in cases where one bit consists of 8 Tq's.
• If one-time sampling is selected, the value sampled at Sampling Point (1) is assumed to be the
value of the bit.
• If three-time sampling is selected, the value of the bit is determined by majority from CAN bus
values sampled at Sampling Points (1), (2) and (3).
1Tq
1 Bit
13.4 Initializing the CAN Module
Figure 13.4.1 Example of Bit Timing
(5) Setting the ID mask registers
Set the values of ID mask registers (Global Mask Register, Local Mask Register A and Local Mask Register
B) that are used in acceptance filtering of received messages.
(6) Settings for use in BasicCAN mode
• Set the CAN Extended ID Register IDE14 and IDE15 bits. (We recommend setting the same value in these bits.)
• Set IDs in message slots 14 and 15.
• Set the Message Control Registers 14 and 15 for data frame reception (H’40).
(7) Settings for use in single-shot mode
Using the CAN Mode Register (CANnMODE) and CAN Control Register (CANnCNT), select CAN module
operation mode (BasicCAN, loopback mode) and the clock source for the timestamp counter.
(8) Setting CAN module operation mode
In the CAN Single-Shot Mode Control Register, set the slot that is to be operated in single-shot mode.
(9) Releasing the CAN module from reset
When settings (1) through (7) above are finished, clear the CAN Control Register (CANnCNT)’s forcible reset
(FRST) and reset (RST) bits to "0". Then, after detecting 11 consecutive recessive bits on the CAN bus, the
CAN module becomes ready to communicate.