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MC68HC05T16 Datasheet, PDF (49/128 Pages) Motorola, Inc – High-density complementary metal oxide semiconductor (HCMOS) microcontroller unit | |||
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TOF - Timer Overï¬ow Flag
1 (set) â Timer Overï¬ow has occurred.
0 (clear) â No timer overï¬ow has occurred.
This bit is set when the free-running counter overï¬ows from $FFFF to $0000; a timer overï¬ow
interrupt will occur, if TOIE (bit 5 in Timer Control register $10) is set. TOF is cleared by reading
the TSR and the counter low register ($19).
When using the timer overï¬ow function and reading the free-running counter at random times to
measure an elapsed time, a problem may occur whereby the timer overï¬ow ï¬ag is unintentionally
cleared if:
1) the timer status register is read or written when the TOF is set, and
2) the LSB of the free-running counter is read, but not for the purpose of
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servicing the ï¬ag.
Reading the alternate counter register instead of the counter register will avoid this potential
problem.
TCAPS - Timer Capture State
1 (set) â TCAP pin is a logic high.
0 (clear) â TCAP pin is a logic low.
This bit reï¬ects the logic level at the TCAP pin.
5.1.6 Programmable Timer Timing Diagrams
The relationships between the internal clock signals, the counter contents and the status of the
ï¬ag bits are shown in the following diagrams. It should be noted that the signals labelled âinternalâ
(processor clock, timer clocks and Reset) are not available to the user.
MC68HC05T16
TIMERS
TPG
MOTOROLA
5-7
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