7540 datasheet(166/366 Pages) RENESAS

166 / 366 page

2-90

REJ09B0018-0200Z

Rev.2.00

Jun 21, 2004

APPLICATION

7540 Group

2.5 Timer Y and timer Z

Fig. 2.5.34 Example of control procedure

Timer Z primary (Address 2716)

Prescaler Z (Address 2516)

CLI

RESET

Set pull-up control register

Set port P1P3 control register

TYZM(Address 2016)

Timer Z count start (Note 7)

Set the standby state to accept one-shot start

trigger

INTEDGE(Address 3A16)

INT0 rising edge active

Set the interrupt edge selection register

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.

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