h8s-2649 Renesas Electronics Corporation., h8s-2649 Datasheet - Page 496

• Manufacturer Part Number: h8s-2649
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2600 Series
• Manufacturer: Renesas Electronics Corporation.

Section 14 Controller Area Network (HCAN)
CPU interrupt source settings: The CPU interrupt source is set by the interrupt mask register
(IMR) and mailbox interrupt mask register (MBIMR). Transmission acknowledge and
transmission abort acknowledge interrupts can be generated for individual mailboxes in the
mailbox interrupt mask register (MBIMR).
Arbitration field setting: The arbitration field is set by the message control registers MCx[5] to
MCx[8] in a transmit mailbox. For a standard format, an 11-bit identifier (ID-28 to ID-18) and the
RTR bit are set, and the IDE bit is cleared to 0. For an extended format, a 29-bit identifier (ID-28
to ID-0) and the RTR bit are set, and the IDE bit is set to 1.
Control field setting: In the control field, the byte length of the data to be transmitted is set within
the range of zero to eight bytes. The register to be set is the message control register MCx[1] in a
transmit mailbox.
Data field setting: In the data field, the data to be transmitted is set within the range zero to eight.
The registers to be set are the message data registers MDx[1] to MDx[8]. The byte length of the
data to be transmitted is determined by the data length code in the control field. Even if data
exceeding the value set in the control field is set in the data field, up to the byte length set in the
control field will actually be transmitted.
Message transmission: If the corresponding mailbox transmit wait bit (TXPR1 to TXPR15) in
the transmit wait register (TXPR) is set to 1 after message control and message data registers have
been set, the message enters transmit wait state. If the message is transmitted error-free, the
corresponding acknowledge bit (TXACK1 to TXACK15) in the transmit acknowledge register
(TXACK) is set to 1, and the corresponding transmit wait bit (TXPR1 to TXPR15) in the transmit
wait register (TXPR) is automatically cleared to 0. Also, if the corresponding bit (MBIMR1 to
MBIMR15) in the mailbox interrupt mask register (MBIMR) and the mailbox empty interrupt bit
(IRR8) in the interrupt mask register (IMR) are both simultaneously set to enable interrupts,
interrupts may be sent to the CPU.
If transmission of a transmit message is aborted in the following cases, the message is
retransmitted automatically:
• CAN bus arbitration failure (failure to acquire the bus)
• Error during transmission (bit error, stuff error, CRC error, frame error, or ACK error)
Rev. 2.00 Dec. 05, 2005 Page 458 of 724
REJ09B0200-0200