HD6417750RF240V Datasheet, PDF (458/606 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2600 Series

Section 15 Controller Area Network (HCAN)
CPU Interrupt Source Settings: CPU interrupt source settings are made in the interrupt mask
register (IMR) and mailbox interrupt register (MBIMR). The message to be received is also
specified. Data frame and remote frame receive wait interrupt requests can be generated for
individual mailboxes in the MBIMR.
Arbitration Field Setting: To receive a message, the message identifier must be set in advance in
the message control registers (MCx[1] to MCx[8]) for the receiving mailbox. When a message is
received, all the bits in the receive message identifier are compared with those in each message
control register identifier, and if a 100% match is found, the message is stored in the matching
mailbox. Mailbox 0 has a local acceptance filter mask (LAFM) that allows Don't care settings to
be made. The LAFM setting can be made only for mailbox 0. By making the Don't care setting for
all the bits in the receive message identifier, messages of multiple identifiers can be received.
Examples:
• When the identifier of mailbox 1 is 010_1010_1010 (standard format), only one kind of
message identifier can be received by mailbox 1:
Identifier 1:
010_1010_1010
• When the identifier of mailbox 0 is 010_1010_1010 (standard format) and the LAFM setting is
000_0000_0011 (0: Care, 1: Don't care), a total of four kinds of message identifiers can be
received by mailbox 0:
Identifier 1:
010_1010_1000
Identifier 2:
010_1010_1001
Identifier 3:
010_1010_1010
Identifier 4:
010_1010_1011
Message Reception: When a message is received, a CRC check is performed automatically. If the
result of the CRC check is normal, ACK is transmitted in the ACK field irrespective of whether
the message can be received or not.
• Data frame reception
If the received message is confirmed to be error-free by the CRC check, the identifier in the
mailbox (and also LAFM in the case of mailbox 0 only) and the identifier of the receive
message, are compared. If a complete match is found, the message is stored in the mailbox.
The message identifier comparison is carried out on each mailbox in turn, starting with
mailbox 0 and ending with mailbox 15. If a complete match is found, the comparison ends at
that point, the message is stored in the matching mailbox, and the corresponding receive
complete bit (RXPR0 to RXPR15) is set in the receive complete register (RXPR). However,
when a mailbox 0 LAFM comparison is carried out, even if the identifier matches, the mailbox
comparison sequence does not end at that point, but continues with mailbox 1 and then the
Rev. 7.00 Sep. 11, 2009 Page 422 of 566
REJ09B0211-0700