R5S72011 RENESAS [Renesas Technology Corp], R5S72011 Datasheet - Page 888

• Manufacturer Part Number: R5S72011
• Description: 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7200 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

Section 19 Controller Area Network (RCAN-ET)
The RCAN-ET has two state machines. One is for transmission, and the other is for reception.
1-1: When a TXPR bit(s) is set while the CAN bus is idle, the internal arbitration starts running
1-2: Operations for both transmission and reception starts at SOF. Since there is no reception
2-1: At crc delimiter, internal arbitration to search next message transmitted starts.
2-2: Operations for both transmission and reception starts at SOF. Because of a reception frame
3-1: At crc delimiter, internal arbitration to search next message transmitted starts.
3-2: Operations for both transmission and reception starts at SOF. Since a transmission frame has
Internal arbitration for the next transmission is also performed at the beginning of each error
delimiter in case of an error is detected on the CAN Bus. It is also performed at the beginning of
error delimiters following overload frame.
As the arbitration for transmission is performed at CRC delimiter, in case a remote frame request
is received into a Mailbox with ATX = 1 the answer can join the arbitration for transmission only
at the following Bus Idle, CRC delimiter or Error Delimiter.
Depending on the status of the CAN bus, following the assertion of the TXCR, the corresponding
Message abortion can be handled with a delay of maximum 1 CAN Frame.
Rev. 2.00 Sep. 07, 2007 Page 860 of 1164
REJ09B0321-0200
CAN bus
state
RCAN-ET
scheduler state
Scheduler
start point
TXPR/TXCR/
Error/Arb-Lost
Set Point
immediately and the transmission is started.
frame, RCAN-ET becomes transmitter.
with higher priority, RCAN-ET becomes receiver. Therefore, Reception is carried out instead
of transmitting Frame-3.
higher priority than reception one, RCAN-ET becomes transmitter.
Bus Idle
CTx Arb for
1-1
Interm:
SOF:
EOF:
Message:
Frame-1
Figure 19.10 Internal Arbitration for transmission
SOF
CTx/CRx Arb for
Intermission Field
Start Of Frame
End Of Frame
Arbitration + Control + Data + CRC + Ack Field
Frame-1
1-2
Transmission
Message
Frame-1
CTx Arb for
Frame-3
2-1
EOF Interm
CTx/CRx Arb for
SOF
Frame-3/2
2-2
Reception
Message
Frame-2
CTx Arb for
Frame-3
3-1
EOF Interm
Transmission
CTx/CRx Arb for
SOF
Frame-3
Frame-3
3-2