HD64F3642AHV Datasheet, PDF (236/551 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 9 Timers
Auto-Reload Timer Operation: Setting bit TMB17 in TMB1 to 1 causes timer B1 to function as
an 8-bit auto-reload timer. When a reload value is set in TLB1, the same value is loaded into
TCB1, becoming the value from which TCB1 starts its count.
After the count value in TCB1 reaches H'FF, the next clock signal input causes timer B1 to
overflow. The TLB1 value is then loaded into TCB1, and the count continues from that value. The
overflow period can be set within a range from 1 to 256 input clocks, depending on the TLB1
value.
The clock sources and interrupts in auto-reload mode are the same as in interval mode.
In auto-reload mode (TMB17 = 1), when a new value is set in TLB1, the TLB1 value is also set in
TCB1.
Event Counter Operation: Timer B1 can operate as an event counter, counting rising or falling
edges of an external event signal input at pin TMIB. External event counting is selected by setting
bits TMB12 to TMB10 in timer mode register B1 (TMB1) to all 1s (111).
When timer B1 is used to count external event input, bit INTEN6 in IENR3 should be cleared to 0
to disable INT₆ interrupt requests.
9.3.4 Timer B1 Operation States
Table 9.7 summarizes the timer B1 operation states.
Table 9.7 Timer B1 Operation States
Operation Mode Reset
TCB1 Interval
Reset
Auto reload Reset
TMB1
Reset
Active
Functions
Functions
Functions
Sleep
Functions
Functions
Retained
Watch
Halted
Halted
Retained
Sub-
active
Sub-
sleep
Standby
Halted Halted Halted
Halted Halted Halted
Retained Retained Retained
Rev. 6.00 Sep 12, 2006 page 214 of 526
REJ09B0326-0600