Section 12 16-Bit Free-Running Timer (FRT)
Rev. 2.00 Mar 09, 2006 page 540 of 906
REJ09B0292-0200
12.7.4
Internal Clock Switching and Counter Operation
FRC will sometimes begin incrementing because of the timing of switching between internal
clocks. Table 12.4 shows the relationship between internal clock switching timing (CKS1 and
CKS0 bit rewrites) and FRC operation.
When an internal clock is used, the FRC clock is generated when the falling edge of an internal
clock (created by dividing the system clock (
φ
)) is detected. When a clock is switched to high
before the switching and to low after switching, as shown in case 3 in table 12.4, the switchover is
considered a falling edge and an FRC clock pulse is generated, causing FRC to increment. FRC
may also increment when switching between an internal clock and an external clock.
Table 12.4 Internal Clock Switching and FRC Operation
No.
Timing of Rewrite of
CKS1 and CKS0 Bits
FRC Operation
1
Low-to-low switch
Clock before
switching
Clock after
switching
FRC clock
FRC
N
N + 1
Rewrite of CKS bit
2
Low-to-high switch
N
N + 1
N + 2
Clock before
switching
Clock after
switching
FRC clock
FRC
Rewrite of CKS bit
Summary of Contents for SH7616
Page 10: ...Rev 2 00 Mar 09 2006 page x of xxvi ...
Page 132: ...Section 2 CPU Rev 2 00 Mar 09 2006 page 106 of 906 REJ09B0292 0200 ...
Page 568: ...Section 12 16 Bit Free Running Timer FRT Rev 2 00 Mar 09 2006 page 542 of 906 REJ09B0292 0200 ...
Page 582: ...Section 13 Watchdog Timer WDT Rev 2 00 Mar 09 2006 page 556 of 906 REJ09B0292 0200 ...
Page 706: ...Section 16 Serial I O SIO Rev 2 00 Mar 09 2006 page 680 of 906 REJ09B0292 0200 ...
Page 820: ...Section 19 Pin Function Controller PFC Rev 2 00 Mar 09 2006 page 794 of 906 REJ09B0292 0200 ...
Page 932: ...Appendix D Package Dimensions Rev 2 00 Mar 09 2006 page 906 of 906 REJ09B0292 0200 ...
Page 935: ...SH7616 Hardware Manual ...