SH7205 Datasheet, PDF (1063/1904 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7200 Series

Section 20 Controller Area Network (RCAN-TL1)
20.9 Usage Notes
20.9.1 Notes on Port Setting for Multiple Channels Used as Single Channel
The RCAN-TL1 in this LSI has two channels and some of these channels can be used as a single
channel. When using multiple channels as a single channel, keep the following in mind.
RCAN0
(32 Mailboxes)
CTx0
CRx0
CTx1
PF4
RCAN1
(32 Mailboxes)
CRx1
PF3
Figure 20.30 Connection Example when Using RCAN-TL1 as 1-Channel Module
(64 Mailboxes × 1 Channel)
1. No ACK error is detected even when any other nodes are not connected to the CAN bus. This
occurs when channel 1 transmits an ACK in the ACK field in response to a message channel 0
has transmitted.
Channel 1 receives a message which channel 0 has transmitted on the CAN bus and then
transmits an ACK in the ACK field. After that, channel 0 receives the ACK.
To avoid this, make channel 1 which is not currently used for transmission the listen-only
mode (TST[2:0] = B'001) or the reset state (MCR0 = 1). With this setting, only a channel
which transmits a message transmits an ACK.
2. Internal arbitration for channels 0 and 1 is independently controlled to determine the order of
transmission.
Although the internal arbitration is performed on 31 Mailboxes at a time, it is not performed on
64 Mailboxes at a time even though multiple channels function as a single channel.
3. Do not set the same transmission message ID in both channels 0 and 1.
Two messages may be transmitted from the two channels after arbitration on the CAN bus.
Rev. 1.00 Mar. 25, 2008 Page 1031 of 1868
REJ09B0372-0100