Overview Of 8/16-Bit Timer/Counter; Table 7.1-1 Interval Time And Square Wave Output Ranges Of Timer 1 In 8-Bit Mode - Fujitsu F2MC-8L Series Hardware Manual

CHAPTER 7 8/16-BIT TIMER/COUNTER
7.1

Overview of 8/16-bit Timer/Counter

The 8/16-bit timer/counter consists of two 8-bit counters (timer 1 and timer 2) that can
be used either separately (in 8-bit mode) or in series (in 16-bit mode).
Timer 1 selectively provides either the interval timer function for incrementing the
count in synchronization with one of three different internal count clocks or the
counter function for incrementing the count in synchronization with the clock input
through an external pin. The output from timer 1 can be used to output a square wave
at an arbitrary frequency. Timer 2 has only the interval timer function using one of
three different internal count clocks. In 16-bit mode, timer 2 is connected to timer 1.
Interval Timer Function
The interval timer function generates interrupts repeated at variable time intervals.
The interval timer function can also output a square wave at an arbitrary frequency while
inverting the output level of the pin (TO pin) at the same time intervals (by timer 1 in 8-bit mode
or by the 16-bit timer).
• In 8-bit -mode, timers 1 and 2 operate separately as independent interval timers each
operating in a cycle between 1 and 2
• In 16-bit mode, the two timers operate as a single 16-bit timer with timer 1 as the high-order
timer and timer 2 as the low-order one. The 16-bit timer can serve as an interval timer
operating in a cycle between 1 and 2
• The count clock can be selected from among three different internal count clocks. (When
the external clock is selected for timer 1, it functions as a counter.)
• The output cycle of timer 1 can be used as the clock cycle for continuous activation of the A/
D converter.
Tables 7.1-1 to 7.1-3 list the interval time and square wave output ranges in each operating
mode.

Table 7.1-1 Interval Time and Square Wave Output Ranges of Timer 1 in 8-bit Mode

Count clock cycle
Internal count clock
External clock
158
Interval time
2 t 2 t
inst inst
5
32 t 2 t
inst inst
9
512 t 2 t
inst inst
1 t 1 t
ext ext
8
times the count clock cycle.
16
times the count clock cycle.
Square wave output range (Hz)
9
to 2 t
inst
13
to 2 t
inst
17
to 2 t
inst
8
to 2 t
ext
2 10
1/(2 t ) to 1/(2 t
inst inst
6 14
1/(2 t ) to 1/(2 t
inst inst
10 18
1/(2 t ) to 1/(2 t
inst inst
9
1/(2 t ) to 1/(2 t )
ext ext
)
)
)