Timer B1 Operation States - Renesas H8 Series Hardware Manual

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 INT interrupt requests.
6
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
TCB1 Interval
Auto reload
TMB1
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Reset Active
Reset Functions
Reset Functions
Reset Functions
Sleep Watch
Functions Halted
Functions Halted
Retained Retained
Sub- Sub-
active sleep
Halted Halted
Halted Halted
Retained Retained Retained
Standby
Halted
Halted