FUJITSU F2MC-8L F202RA - Manual (Page 134)

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CHAPTER 5 TIME-BASE TIMER
5.2 Configuration of Time-base Timer
The time-base timer consists of the following four function blocks.
• Time-base counter
• Counter clear circuit
• Interval timer selector
• Time-base timer control register (TBTC)
■ Block Diagram of Time-base Timer
Figure 5.2-1 Block Diagram of Time-base Timer
●
Time-base timer counter
A 21-bit up counter that accepts the oscillation frequency divided by two as the count clock and stops
operating when oscillation stops.
●
Counter clear circuit
Clears the counter when the TBTC register is set (TBR = 0), stop mode is entered (STBC: STP = 1), or a
power-on reset occurs.
●
Interval timer selector
Selects 1 bit for the interval timer from four bits in the time-base counter. When the specified bit overflows,
an interrupt occurs.
● Time-base timer control register (TBTC)
Selects a time interval, clears the counter, controls interrupts, or checks the status.
TB0F TBIE TBC1 TBC0 TBR
OF
OF
OF
OF
F
CH : O s cill a tion fre qu ency
X2 1
Time- bas e timer co u nter
X2 2 X2 3 X2 6 X2 7 X2 8 X2 9 X2 10 X2 11 X2 12 X2 1 3 X2 14 X2 15 X2 16 X2 17 X2 20 X2 21
To A/D converter
To w a tchdog timer
F CH
divided
b y two
Cle a ring co u nter To clock control
s ection o s cill a tion
s t ab iliz a tion time
s elector
Cle a ring w a tchdog timer
Power-on re s et
S t a rting s top mode
(in norm a l mode)
Co u nter
cle a r
circ u it
Interv a l timer
s elector
IRQ7 (time- bas e timer interr u pt)
OF: Overflow
Time- bas e timer control regi s ter (TBTC)