Unde
Usage precaution
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Mitsubishi microcomputers
M30201 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
108
Timer B (timer mode, event counter mode)
(1) Reading the timer Bi register while a count is in progress allows reading , with arbitrary timing, the
value of the counter. Reading the timer Bi register with the reload timing gets “FFFF
16
”. Reading the
timer Bi register after setting a value in the timer Bi register with a count halted but before the counter
starts counting gets a proper value.
Timer B (pulse period/pulse width measurement mode)
(1) If changing the measurement mode select bit is set after a count is started, the timer Bi interrupt
request bit goes to “1”.
(2) When the first effective edge is input after a count is started, an indeterminate value is transferred to
the reload register. At this time, timer Bi interrupt request is not generated.
Timer X (timer mode)
(1) Reading the timer Xi register while a count is in progress allows reading, with arbitrary timing, the
value of the counter. Reading the timer Xi register with the reload timing gets “FFFF
16
”. Reading the
timer A0 register after setting a value in the timer Xi register with a count halted but before the counter
starts counting gets a proper value.
Timer X (event counter mode)
(1) Reading the timer Xi register while a count is in progress allows reading, with arbitrary timing, the
value of the counter. Reading the timer Xi register with the reload timing gets “FFFF
16
” by underflow
or “0000
16
” by overflow. Reading the timer Xi register after setting a value in the timer Xi register with
a count halted but before the counter starts counting gets a proper value.
(2) When stop counting in free run type, set timer again.
Timer X (one-shot timer mode)
(1) Setting the count start flag to “0” while a count is in progress causes as follows:
The counter stops counting and a content of reload register is reloaded.
The TXi
INOUT
pin outputs “L” level.
The interrupt request generated and the timer Xi interrupt request bit goes to “1”.
(2) The timer Xi interrupt request bit goes to “1” if the timer's operation mode is set using any of the
following procedures:
Selecting one-shot timer mode after reset.
Changing operation mode from timer mode to one-shot timer mode.
Changing operation mode from event counter mode to one-shot timer mode.
Therefore, to use timer Xi interrupt (interrupt request bit), set timer Xi interrupt request bit to “0” after
the above listed changes have been made.