7540 datasheet(154/366 Pages) RENESAS

154 / 366 page

2-78

REJ09B0018-0200Z

Rev.2.00

Jun 21, 2004

APPLICATION

7540 Group

2.5 Timer Y and timer Z

Notes 1: In the programmable waveform generation mode, values of TYS, EXPYP, and EXPYS are

valid by writing to TYP because the setting to them is executed all at once by writing to

TYP. Even when changing TYP is not required, write the same value again.

2: In the programmable waveform generation mode, when the setting value is changed while

the waveform is output, set by software in order not to execute the writing to TYP and the

timing of timer underflow during the secondary interval simultaneously.

An example of a measurement is shown below.

ex.) The underflow by the primary and the underflow by secondary are stored by polling

etc. using timer Y interrupt.

Writing is performed in by judging that there is no problem if the underflow by secondary

is completed with reference to primary write operation before.

(Depending on a primary and a secondary setting values, and primary write timing, it

may be impossible.)

3: The waveform extension function by the timer Y waveform extension control bits can be

used only when “0016” is set to Prescaler Y.

When the value other than “0016” is set to Prescaler Y, be sure to set “0” to EXPYP and

EXPYS.

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 and EXPZS. Also, when the timer Y underflow

is selected as the timer Z count source, the waveform extension function cannot be used.

4: When using this mode, be sure to set “1” to the timer Y write control bit to select “write

to latch only”.

5: When TYS is read out, the undefined value is read out. However, while timer Y counts the

setting value of TYS, the count value during the secondary interval can be obtained by

reading the timer Y primary.

6: In order to use TYOUT pin, set “1” to bit 1 of the port P0 direction register (output mode).

Figure 2.5.23 shows the timing diagram of the programmable waveform generation mode.

7540 Datasheet(PDF) 154 Page - Renesas Technology Corp