UPD17062 datasheet(142/298 Pages) RENESAS

142 / 298 page

140

µPD17062

As shown in Fig. 12-5, if the timer carry FF setting time interval is switched, the timer error that occurs before

the BTM0CY flag is set for the first time is as follows:

-tSET < error < tCHECK

where tSET

: Newly selected timer carry FF setting time interval

tCHECK : Time interval at which the BTM0CY flag is checked

The internal pulses, 4 Hz, 10 Hz, 200 Hz, and 1 kHz, have a phase difference. However, this phase difference

is less than a newly selected set pulse interval, and included in the timer error described above.

See Section 12.6 for details about the phase difference of each pulse.

Fig. 12-5

Timer Error That Occurs When the Timer Carry FF Setting Time Interval Is Switched from A to B

(a) Timer error of -tSET

(b) Timer error of tCHECK

tSET

= 0

SKT1

BTM0CY

Internal pulse A

Internal pulse B

Timer carry FF set pulse

BTM0CY flag

True timer interval

Actual timer interval

Time interval switched here

If the BTM0CY flag is checked right

after the timer setting time interval is

switched, it appears to be 1, and therefore,

the timer error is -tSET.

Actual timer interval

True timer interval

Time interval switched here

If the timer setting time interval is

switched right after the BTM0CY flag

is checked, the BTM0CY flag remains

reset for one cycle, and therefore, the

timer error is tCHECK.

= 0

tCHECK

UPD17062 Datasheet(PDF) 142 Page - Renesas Technology Corp