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18
MITSUBISHI MICROCOMPUTERS
M37735MHBXXXFP
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
PRELIMINAR
Y
Notice:
This
is not
a final
specification.
Some
parametric
limits
are
subject
to change.
When bit 2 of the timer Ai mode register is “1”, the output is generated
from TAiOUT pin. The output is toggled each time the contents of the
counter reaches to 000016. When the contents of the count start flag
is “0”, “L” is output from TAiOUT pin.
When bit 2 is “0”, TAiOUT can be used as a normal port pin.
When bit 4 is “0”, TAiIN can be used as a normal port pin.
When bit 4 is “1”, counting is performed only while the input signal
from the TAiIN pin is “H” or “L” as shown in Figure 16. Therefore, this
can be used to measure the pulse width of the TAiIN input signal.
Whether to count while the input signal is “H” or while it is “L” is
determined by bit 3. If bit 3 is “1”, counting is performed while the
TAiIN pin input signal is “H” and if bit 3 is “0”, counting is performed
while it is “L”.
Note that the duration of “H” or “L” on the TAiIN pin must be two or
more cycles of the timer count sourse.
When data is written to the timer Ai register with timer Ai halted, the
same data is also written to the reload register and the counter. When
data is written to timer Ai which is busy, the data is written to the
reload register, but not to the counter. The counter is reloaded with
new data from the reload register at the next reload time. The contents
of the counter can be read at any time.
When the value set in the timer Ai register is n, the timer frequency
dividing ratio is 1/(n + 1).
Fig. 14 Timer Ai mode register bit configuration during timer mode
70
0 0 : Always “00” in timer mode
0
0 : No pulse output (TAiOUT is normal port pin)
1 : Pulse output
0 ! : No gate function (TAiIN is normal port pin)
1 0 : Count only while TAiIN input is “L”
1 1 : Count only while TAiIN input is “H”
62
3
4
51
00
0 : Always “0” in timer mode
Clock source selection bit
0 0 : Select f2
0 1 : Select f16
1 0 : Select f64
1 1 : Select f512
Timer A0 mode register
5616
Timer A1 mode register
5716
Timer A2 mode register
5816
Timer A3 mode register
5916
Timer A4 mode register
5A16
Addresses