SH7205 Datasheet, PDF (1047/1904 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7200 Series

Section 20 Controller Area Network (RCAN-TL1)
Slave
<Configuration> Cycle Time varies between L and Time_Ref + L
Cycle Time = 0
=L
= Time_Ref
= Time_Ref + L
Time_Mark 1 Time_Mark 2 Time_Mark 3 Time_Mark 4 Time_Mark 5 Time_Mark 6 Time_Ref
TTT in MB24 TTT in MB25 TTT in MB26 TTT in MB27 TTT in MB28 TTT in MB29 TTT in MB30
Watch_Trigger
TCMR2
copy CCR from received time reference
CCR isn't incremented unlike time master
<Normal Operation>
CCR = 0
capture timestamp
at SOF of reception
Time_Mark 1 Time_Mark 2 Time_Mark 3 Time_Mark 4 Time_Mark 5 Time_Mark 6 Time_Ref
TTT in MB24 TTT in MB25 TTT in MB26 TTT in MB27 TTT in MB28 TTT in MB29 TTT in MB30
CCR = 0
Ref_Mark and CCR are updated
at successful end of time reference reception
CCR = 1
L
Time_Mark 1 Time_Mark 2 Time_Mark 3 Time_Mark 4 Time_Mark 5 Time_Mark 6 Time_Ref
TTT in MB24 TTT in MB25 TTT in MB26 TTT in MB27 TTT in MB28 TTT in MB29 TTT in MB30
Cycle Time
= Time_Ref
= Time_Ref + L
Figure 20.20 Time Slave
• Function to be implemented by software
Some of the TTCAN functions need to be implemented in software. The main details are reported
hereafter. Please refer to ISO-11898-4 for more details.
 Change from Init_Watch_Trigger to Watch_Trigger
RCAN-TL1 offers the two registers TCMR0 and TCMR2 as H/W support for
Init_Watch_Trigger and Watch_Trigger respectively. The SW is requested to enable
TCMR0 and disable TCMR2 up to the first reference message is detected on the CAN Bus
and then disable TCMR0 and enable TCMR2.- Schedule Synchronization state machine.
Only reception of Next_is_Gap interrupt is supported. The application needs to take care of
stopping all transmission at the end of the current basic cycle by setting the related TXCR
flags.Master-Slave Mode control.
Only automatic cycle time synchronization and CCR increment is supported.
 Message status count
Software has to count scheduling errors for periodic messages in exclusive windows.
Rev. 1.00 Mar. 25, 2008 Page 1015 of 1868
REJ09B0372-0100