Chapter 8
8-bit Timer
VIII - 32 Interval Timer
8.4 Interval Timer
8.4.1 Interval Timer Operation
Interval timer function is the function that can constantly generate interrupts at regular time intervals.
■ Clock Source Selection
The generation cycle of timer interrupts is set in advance by the clock source selection and the setting value of the
base register (TMnBR). The clock source can be selected by the timer as below.
Table:8.4.1 The Clock Source at the Timer Operating and 1 Count Time‘
Clock source 1 count time Timer 0 Time 1 Timer 2 Timer 3
IOCLK 33ns OOOO
IOCLK/8 267ns OOOO
IOCLK/32 1.07µsOOOO
IOCLK/128 4.27µsO- O-
Timer 0 underflow - - O O O
Timer 1 underflow - O - O O
Timer 2 underflow - O O - O
1 count time is calculated with 10MHz, 6 multiplication and IOCLK=MCLK/2.
Clock source 1 count time Timer 4 Timer 5 Timer 6 Timer 7
IOCLK 33ns OOOO
IOCLK/8 267ns OOOO
IOCLK/32 1.07µsOOOO
IOCLK/128 4.27µsO- O-
Timer 4 underflow - - O O O
Timer 5 underflow - O - O O
Timer 6 underflow - O O - O
1 count time is calculated with 10MHz, 6 multiplication and IOCLK=MCLK/2.
Clock source 1 count time Timer 14 Timer 15 Timer 16 Timer 17
IOCLK 33ns OOOO
IOCLK/8 267ns OOOO
IOCLK/32 1.07µsOOOO
IOCLK/128 4.27µsO- O-
Timer 14 underflow - - O O O
Timer 15 underflow - O - O O
Timer 16 underflow - O O - O
1 count time is calculated with 10MHz, 6 multiplication and IOCLK=MCLK/2.
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