Usage Notes On The Multi-Functional Timer - Fujitsu MB90460 Series Hardware Manual

14.7

Usage Notes on the Multi-functional Timer

Notes on using the multi-functional timer are given below.
■ Usage Notes on the 16-bit Free-run Timer
●
Notes about using a program for setting
• After reset, the timer value is "0000
after timer enable (TCCSL:STOP=0).
• Since the timer mode bit (TCCSL:MODE) has a buffer, changing timer mode will take effect in next
count cycle. Zero detect interrupt is always generated when timer mode is changed from up-count to up-
down count mode.
• Software clear timer (TCCSL:SCLR=1) will initialize the timer but not generate zero detect interrupt.
●
Notes about interrupts
• When the IRQZF bit of the timer control status register (TCCSH) is set to "1" and an interrupt request is
enabled (TCCSH:IRQZE=1), control cannot be returned from interrupt processing. Always clear the
IRQZF bit.
• When the ICLR bit of the timer control status register (TCCSH) is set to "1" and an interrupt request is
enabled (TCCSH:ICRE=1), control cannot be returned from interrupt processing. Always clear the
ICLR bit.
• Since the 16-bit free-run timer shares an interrupt vector with other resource, interrupt causes must be
checked carefully by the interrupt processing routine when interrupts are used.
Also, when EI
■ Usage Notes on the 16-bit Output Compare
●
Notes about interrupts
• When the IOP bit of the compare control register (OCS0/OCS2/OCS4) is set to "1" and an interrupt
request is enabled (OCS0/OCS2/OCS4:IOE=1), control cannot be returned from interrupt processing.
Always clear the IOP bit.
• Since the 16-bit output compare shares an interrupt vector with other resource, interrupt causes must be
checked carefully by the interrupt processing routine when interrupts are used.
Also, when EI
", zero detect interrupt flag will be set to "1" in next count clock
H
2
OS is used by the 16-bit free-run timer, shared resource interrupts must be disabled.
2
OS is used by the 16-bit output compare, shared resource interrupts must be disabled.
CHAPTER 14 MULTI-FUNCTIONAL TIMER
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