Datasheet

9 - CAPTURE/COMPARE (CAPCOM) UNITS ST10F269
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* The CAPCOM2 unit provides 16 capture inputs, but only 12 compare outputs. CC24I to CC27I are inputs only.
Figure 13 : Block Diagram of CAPCOM Timers T0 and T7
Figure 14 : Block Diagram of CAPCOM Timers T1 and T8
Note: When an external input signal is
connected to the input lines of both T0 and
T7, these timers count the input signal
synchronously. Thus the two timers can be
regarded as one timer whose contents can
be compared with 32 capture registers.
When a capture/compare register has been
selected for capture mode, the current contents of
the allocated timer will be latched (captured) into
the capture/compare register in response to an
external event at the port pin which is associated
with this register. In addition, a specific interrupt
request for this capture/compare register is
generated.
Either a positive, a negative, or both a positive and
a negative external signal transition at the pin can
be selected as the triggering event. The contents
of all registers which have been selected for one
of the five compare modes are continuously
compared with the contents of the allocated
timers.
When a match occurs between the timer value
and the value in a capture /compare register,
specific actions will be taken based on the
selected compare mode (see Table 9).
The input frequencies f
Tx
, for the timer input
selector Tx, are determined as a function of the
CPU clocks. The timer input frequencies,
resolution and periods which result from the
selected pre-scaler option in TxI when using a
40MHz CPU clock on PQFP144 devices (or a
32MHz CPU clock on TQFP144 devices) are
listed in Table 10 and Table 11 .
The numbers for the timer periods are based on a
reload value of 0000h. Note that some numbers
may be rounded to 3 significant figures.
Pin
X
Txl
CPU
Clock
TxR
MUX
GPT2 Timer T6
Over / Underflow
Edge Select
TxIN
Txl
Txl TxM
Input
Control
Reload Register TxREL
CAPCOM Timer Tx TxIR
Interrupt
Request
x = 0, 7
X
Txl
CPU
Clock
TxR
MUX
GPT2 Timer T6
Over / Underflow
TxM
Reload Register TxREL
CAPCOM Timer Tx TxIR
Interrupt
Request
x = 1, 8