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7540 Group User’s Manual
APPLICATION
2-29
2.2 Timer A
Fig. 2.2.20 Example of control procedure
(Timer A setting value “FFFF16”) – (Timer A count
value)
← event in1ms
Timer X interrupt processing routine (1ms interrupt)
“FF16”
1 0
CLI
0
RESET
SEI
CLD
CLT
CPUM(Address 3B16)
←10000X002
f(XIN) until f(XIN) oscillation is stabilized (Note 1)
CPUM(Address 3B16)
←00000X002
Processing
“FF16”
1 0
1 1
1
Set timer X mode register
TXM(Address 2B16)
Timer mode
Timer X count stop
10 0
“0116”
“F916”
Set timer count source set register
TCSS(Address 2E16)
Timer X count source:
f(XIN)/16 selected
00 0
TXM(Address 2B16)
00 0
TXM(Address 2B16)
10 0
TAM(Address 1D16)
TXM(Address 2B16)
0
1
0
00
RTI
TAM(Address 1D16)
0
1
“0116”
“1816”
Set timer A mode register
TAM(Address 1D16)
Timer A count start
TAM(Address 1D16)
Event count mode
Count at falling edge
Timer A count stop
Set timer A mode register
Set port P00 to the input mode.
PULL(Address 1616)
P00 pull-up control bit
0: Pull-up Off
1: Pull-up On
Set pull-up control register
INTEDGE(Address 3A16)
Key-on wakeup disabled
Set “0” to the CNTR1 interrupt enable bit.
(CNTR1 interrupt disabled)
Set “0” to the timer A interrupt enable bit.
(Timer A interrupt disabled)
Set “0” to the timer X interrupt enable bit
(Timer X interrupt disabled)
Initialization
X: This bit is not used here. Set it to “0” or “1” arbitrary.
Notes 1: For the concrete time, ask the oscillator manufacture.
2: When setting the value to timer, set in order of low-order byte and
high-order byte following.
3: 1 ms detection = 1/8 MHz 16 (0116 + 1) (F916 + 1)
Timer A (low-order) (Address 1E16)
Set value to timer A (Note 2)
Timer A (high-order) (Address 1F16)
Set interrupt edge selection register
Set “1” to the timer X interrupt enable bit.
(Timer X interrupt enabled)
Set “0” to the timer X interrupt request bit.
Prescaler X (Address 2C16)
Set value to timer X (Note 3)
Timer X (Address 2D16)
Set timer X mode register
Timer X count start
Set timer A mode register
Timer A count start
Set timer X mode register
Timer X count start
Set timer A mode register
Timer A count stop
Set timer X mode register
Timer X count stop
Timer A (low-order) (Address 1E16)
Set value to timer A (Note 2)
Timer A (high-order) (Address 1F16)
Prescaler X (Address 2C16)
Set value to timer X (Note 3)
Timer X (Address 2D16)
Timer X
division ratio
Timer X
setting value
Prescaler X
setting value