h8s-2628 Renesas Electronics Corporation., h8s-2628 Datasheet - Page 450

• Manufacturer Part Number: h8s-2628
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2600 Series
• Manufacturer: Renesas Electronics Corporation.

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[8] to MCx[1]) 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 complete 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.
The LAFM setting can be made only for mailbox 0. By setting the Don’t Care for all the bits in the
receive message identifier, messages of multiple identifiers can be received.
Examples:
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.
Rev. 3.00 Oct 04, 2005 page 410 of 598
REJ09B0155-0300
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:
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:
Identifier 2:
Identifier 3:
Identifier 4:
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 matching
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 (RXPR15 to RXPR0) in the receive complete register (RXPR) is set.
However, if the identifier matches that of mailbox 0 LAFM, the mailbox comparison sequence
does not end at that point, but continues from mailbox 1. Therefore, the message for mailbox 0
010_1010_1010
010_1010_1000
010_1010_1001
010_1010_1010
010_1010_1011