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Will the next interrupt be delay if timer & latch are written together?

Latest Updated:12/07/2004

Question:

(Timer)   If the timer and latch are written to simultaneously using the timer interrupt routine in order to change the timer interrupt period, will the next interrupt be slightly delayed? [2004/12/07]

Answer:

Timer count continues even during the period after an interrupt is generated to when the interrupt routine is set by the timer value. If the timer and timer latch are simultaneously written to, the timer count in progress will be overwritten. Consequently, interrupt delay time (from interrupt request generation to interrupt routine commencement) and software processing time (from interrupt routine commencement until timer value is set) will be delayed.
To minimize delay when writing simultaneously to the latch and timer, write within the timer interrupt routine as quickly as possible.
In addition, a delay will not be generated when writing to the latch only.
However, the value written when writing to the latch only will not be reflected until the next timer underflow. (#104915)
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