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7540 Group User’s Manual
2-90
APPLICATION
2.5 Timer Y and timer Z
Fig. 2.5.34 Example of control procedure
Timer Z primary (Address 2716)
Prescaler Z (Address 2516)
0
1
00
CLI
RESET
1
0
1
0
1
Set pull-up control register
Set port P1P3 control register
1
TYZM(Address 2016)
Timer Z count start (Note 7)
Set the standby state to accept one-shot start
trigger
0
10
INTEDGE(Address 3A16)
INT0 rising edge active
Set the interrupt edge selection register
1
Phase control processing
q Period measurement of feedback signal
q Analyze of measured value
(determination of timer Z setting value)
INT0 interrupt processing routine
Change of timer Z
RTI
Timer Z primary waveform generation
extended (Note 3)
Initial state: “L”, TZP: “H” interval, TZS:
“L” interval, stop at “L” after underflow
INT0 pin one-shot trigger valid (Note 4)
INT0 pin rising edge trigger (Note 4)
PUM(Address 2416)
TCSS(Address 2E16)
Timer Z count source:
f(XIN)/16 selected
Set port P02 to the output mode.
Set “0” to the timer Z interrupt enable bit.
(Timer Z interrupt disabled)
Set value to timer Z (Notes 3, 5, 6)
Set timer count source set register (Note 3)
TYZM(Address 2016)
Set timer Y, Z mode register
Programmable one-shot
generation mode
Writing to only latch (Note 2)
Timer Z count stop
Set “1” to the INT0 interrupt enable bit.
(INT0 interrupt enabled)
Set “0” to the INT0 interrupt request bit.
Initialization
SEI
CLD
CLT
CPUM(Address 3B16)
← 10000X002
Wait until f(XIN) oscillation is stabilized (Note 1)
CPUM(Address 3B16)
← 00000X002
Set timer Y, Z waveform output control register
X: This bit is not used here. Set it to “0” or “1” arbitrary.
Set port P37 to the input mode.
Notes 1: For the concrete time, ask the oscillator manufacture.
2: When using this mode, be sure to select “write to latch
only”.
3: The waveform extension function by the timer Z waveform
extension control bits can be used only when “0016” is set
to prescaler Z.
When the value other than “0016” is set to prescaler Z, be
sure to set “0” to EXPZP. Also, when the timer Y underflow
is selected as the timer Z count source, the waveform
extension function cannot be used.
4: Stop timer Z to change the INT0 pin one-shot trigger
control bit and INT0 one-shot trigger active edge selection
bit.
5: In the programmable one-shot generation mode, the value
of EXPZP is valid by writing to TZP. Even when changing
TZP is not required, write the same value again.
6: In the programmable one-shot generation mode, when the
setting value is changed while the waveform is output, set
by software in order not to execute the writing to TZP and
the timing of timer Z underflow simultanesously.
7: In this state, timer count is not started.