SH7058 Datasheet, PDF (657/1130 Pages) Renesas Technology Corp – Renesas SuperHTM RISC engine

16.8.7 Notes on Port Settings for 64-Buffer HCAN-II with One Channel
The SH7058 has the HCAN-II with two channels. When using the HCAN-II as a 64-buffer with
one channel, the following notice should be taken at port settings.
HTxD0
HCAN0
(HCAN-II: 32 buffers) _HRxD0
HCAN1
(HCAN-II: 32 buffers)
HTxD1
HRxD1
PL10
PL11
1. When a message is transmitted to the CAN bus without connecting to other nodes, an ACK
error will not occur. For example, when a message is transmitted from HCAN0 in the above
figure, HCAN1 transmits ACK in the ACK field.
HCAN1 which already received the message on the CAN bus transmits ACK in the ACK field
according to the CAN protocol and HCAN0 receives the ACK.
For a countermeasure, please set the channel that will not transmit the message to the reset
state (MCR0 = 1). Accordingly, a channel that will not transmit the message does not transmit
ACK.
2. Internal arbitration which determines the transmission order is independently carried out by
HCAN0 and HCAN1, respectively. The HCAN-II has 31 transmission buffers per channel.
However, internal arbitration cannot be carried out in the range of the 62 transmission buffers.
3. Please do not set the same transmit message ID to HCAN0 and HCAN1.
Otherwise, the same message will be transmitted from the two channels after arbitration on the
CAN bus.
Rev. 3.0, 09/04, page 616 of 1086