Fujitsu F2MC-8L Series Hardware Manual page 189

CHAPTER 7 8/16-BIT TIMER/COUNTER
Count clock selectors 1 and 2
Count clock selectors 1 and 2 are circuits for selecting an input clock. For timer 1 in 8-bit mode
or the 16-bit timer, the input can be selected from among three different internal clocks and one
external clock as well. For timer 2 in 8-bit mode, it can be selected only from among three
different internal clocks.
Counter circuits 1 and 2
Counter circuits 1 and 2 each consist of an 8-bit counter, comparator, comparate data latch, and
timer data register (T1DR or T2DR).
The 8-bit counter increments the count in synchronization with the selected count clock. The
comparator compares the counter and comparate data latch values. When they match, the
counter is cleared and the data register value is set in (loaded to) the comparate data latch.
In 8-bit mode, counter circuits 1 and 2 operate separately as timers 1 and 2. In 16-bit mode, the
two counter circuits operate as a single 16-bit counter with counter circuit 1 serving as its lower
eight bits and counter circuit 2 as the upper eight bits.
Square wave output controller
The square wave output controller generates an interrupt request when the comparator detects
a match either in timer 1 in 8-bit mode or in the 16-bit timer. If square wave output has been
enabled, the output controller inverts the TO pin output.
The square wave output can be initialized to "L" or "H" level.
Timer data registers (T1DR, T2DR)
When read, the timer data registers are used to set data to be compared with the value in each
8-bit counter. When read, the registers return the current value in each counter.
Timer control registers (T1DR, T2DR)
The timer control registers are used to select functions, enable or disable operation, control
interrupts, and to check the state of the 8/16-bit timer/counter.
8/16-bit timer/counter interrupt IRQ3:
An interrupt request of IRQ3 is generated if interrupt request output has been enabled (T1CR: T
"1"IE = "1" for timer 1 in 8-bit mode or for 16-bit timer, or T2CR: T2IE = "1" for timer 2 in 8-bit
mode) when the interval timer or counter value reaches the value set in the data register.
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