Table of Contents
Advertisement
MB90335 Series
9.6
Precautions when Using Time-base Timer
Cautions about influences on peripheral functions due to interrupt request and time-
base timer clearances.
■ Precautions when Using Time-base Timer
●
Clearing Interrupt request
When clearing the interrupt request flag bit (TBOF) in the time-base timer control register (TBTC),
perform while the time-base timer interrupt is masked by the setting of the interrupt level mask register
(ILM) of the interrupt request permission bit (TBIE) or the processor status (PS).
●
Effect from time-base timer clear
By clearing the time-base timer counter, the following operations are affected.
• When using the interval timer function (interval interrupt) in the time-base timer
• When using the watchdog timer
●
Using time-base timer as oscillation stabilization wait time
After power on, since the oscillation clock halts in the main stop mode, oscillation stabilization wait time of
the oscillation clock will be needed using the operation clock supplied from the time-base timer after the
oscillator starts operating. Selection of suitable oscillation stabilization wait time is necessary depending on
the types of resonators connected to the high-speed oscillation pin. For details, see section "5.5 Oscillation
Stabilization Wait Time".
●
Notes on peripheral functions the time-base timer supplies to the clock
The mode that stops the main clock clears the counter, and then the time-base timer stops operation. The
clock supplied from the time-base timer may shorten the "H" level or lengthen the "L" level for up to 1/2
cycle because the clock is supplied from the initial state when the counter of the time-base timer is cleared.
The clock for the watchdog timer is also supplied from the initial status, however, the watchdog timer
operates in the normal cycles because the counter of the watchdog timer is cleared at the same time.
CM44-10137-6E
FUJITSU MICROELECTRONICS LIMITED
CHAPTER 9 TIME-BASE TIMER
9.6 Precautions when Using Time-base Timer
179
Advertisement
Table of Contents
