Mitsubishi Electric M32R Series User Manual page 624

Mitsubishi 32-bit risc single-chip microcomputers

Table of Contents

By using the same ID and setting the same value in mask registers for the two slots, the

possibility of a message-lost trouble when, for example, receiving frames which have many

IDs can be reduced.

Procedure for entering BasicCAN mode

Follow the procedure below during initialization:

Set the IDs for slots 14 and 15 and local mask registers A and B. (We recommend

setting the same value.)

Set the frame types handled by slots 14 and 15 (standard or extended) in the CAN

Extended ID Register. (We recommend setting the same type.)

Set the Message Slot Control Register for slots 14 and 15 to for data frame reception.

Set the BCM bit to 1.

Note 1:Do not change settings of BCM bit when CAN is operating (CAN Status Register CRS bit

Note 2:The first slot that is active after clearing the RST bit is slot 14.

Note 3:Even during BasicCAN mode, slots 0 to 13 can be used as in normal operation.

(6) LBM (Loopback Mode) bit (D14)

When the LBM bit is set to 1, if a receive slot exists whose ID matches that of the frame sent by

the CAN module itself, then the frame can be received.

Note 1:No ACK is returned for the transmit frame.

Note 2:Do not change settings of LBM bit when CAN is operating (CAN Status Register CRS bit

(7) RST (CAN Reset) bit (D15)

When the RST bit is cleared to 0, the CAN module is connected to the CAN bus and becomes

possible to communicate after detecting 11 consecutive recessive bits. Also, the CAN Time

Stamp Count Register thereby starts counting.

When the RST bit is set to 1, the CAN module is reset so that after sending a frame from the slot

which has had a transmit request set, the protocol control unit is reset and the CAN module is

disconnected from the CAN bus. Frames received during this time are processed normally.

Note 1:It is inhibited to set a new transmit request for a while from when the CAN Status

Note 2:When the protocol control unit is reset by setting the RST bit to 1, the CAN Time Stamp

Count Register and CAN Transmit/Receive Error Count Registers are initialized to 0.

Note 3:To restart CAN communication, the FRST and RST bits must be cleared to 0.

13.2 CAN Module Related Registers