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CHAPTER 7 16-bit I/O timer
7.7
Precautions when Using 16-bit Input/Output Timer
This section explains the precautions when using the 16-bit input/output timer.
I Precautions when Using 16-bit Input/Output Timer
G
Precautions when setting 16-bit free-run timer
• Do not change the count clock select bits (TCCS: CLK2, CLK1, CLK0) during the count operation
(TCCS: STOP = 0).
• The counter value of the 16-bit free-run timer is cleared to "0000
can be set by writing any count value to the timer counter data register (TCDT) while the count
operation is stopped (TCCS: STOP = 1).
• Always use a word instruction (MOVW) to set the timer counter data register (TCDT).
G
Precautions on interrupts
• When an overflow interrupt or an input capture interrupt is enabled, clear only the set bit of the overflow
generation flag bit or the input capture valid edge detection flag bit.When clearing the flag bit for an
event that caused an interrupt to be accepted, for example, avoid unconditional clearing of the interrupt
request flag bits for other interrupt trigger events because another input capture interrupt may have been
generated.
• If the interrupt request flag bits in the 16-bit input/output timer (TCCS: IVF, ICS01, ICS23: ICP1, ICP0)
are set to "1" and interrupts corresponding to the set interrupt request flag bits are enabled (TCCS: IVFE
= 1, ICS01, ICS23: ICE1 = 1, ICE0 = 1), it is impossible to return from interrupt processing. Always
clear the interrupt request flag bits.When using the EI
automatically when the EI
242
2
OS is started.
" by reset.The 16-bit free-run timer
H
2
OS, the set interrupt request flag bits are cleared
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