HD64F2638F20J Datasheet, PDF (718/1512 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2600 Series

Section 16 Controller Area Network (HCAN)
H8S/2639, H8S/2638, H8S/2636,
H8S/2630, H8S/2635 Group
Figure 16-9 Reception Flowchart
Interrupt and Receive Message Settings: When mailbox initialization is finished, CPU interrupt
source settings and receive message specifications must be made. Interrupt source settings are
made in the mailbox interrupt register (MBIMR) and interrupt mask register (IMR). To receive a
message, the identifier must be set in advance in the message control (MCx[1] to MCx[8]) for the
receiving mailbox. When a message is received, all the bits in the receive message identifier are
compared, and if a 100% match is found, the message is stored in the matching mailbox. Mailbox
0 (MB0) has a local acceptance filter mask (LAFM) that allows Don’t care settings to be made.
• CPU interrupt source settings
When transmitting, transmission acknowledge and transmission abort acknowledge interrupts
can be masked for individual mailboxes in the mailbox interrupt mask register (MBIMR).
When receiving, data frame and remote frame receive wait interrupts can be masked. Interrupt
register (IRR) interrupts can be masked in the interrupt mask register (IMR).
• Arbitration field setting
In the arbitration field, the identifier (STD_ID0 to STD_ID10, EXT_ID0 to EXT_ID17) of the
message to be received is set. If all the bits in the set identifier do not match, the message is not
stored in a mailbox.
Example: Mailbox 1 010_1010_1010 (standard identifier)
Only one kind of message identifier can be received by MB1
Identifier 1: 010_1010_1010
• Local acceptance filter mask (LAFM) setting
The local acceptance filter mask is provided for mailbox 0 (MB0) only, enabling a Don’t care
specification to be made for all bits in the received identifier. This allows various kinds of
messages to be received.
Example: Mailbox 0
LAFM
010_1010_1010 (standard identifier)
000_0000_0011 (0: Care, 1: Don’t care)
A total of four kinds of message identifiers can be received by MB0
Identifier 1: 010_1010_1000
Identifier 2: 010_1010_1001
Identifier 3: 010_1010_1010
Identifier 4: 010_1010_1011
Page 668 of 1458
REJ09B0103-0800 Rev. 8.00
May 28, 2010