Usage precaution
deeopmen
Preliminary Specifications REV.E
Specifications in this manual are tentative and subject to change.
Mitsubishi microcomputers
M30220 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
152
Timer A (timer mode)
Usage Precaution
Timer A (event counter mode)
(1) Reading the timer Ai register while a count is in progress allows reading, with arbitrary timing, the
value of the counter. Reading the timer Ai register with the reload timing gets “FFFF
16
” by underflow
or “0000
16
” by overflow. Reading the timer Ai register after setting a value in the timer Ai 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.
(1) Reading the timer Ai register while a count is in progress allows reading, with arbitrary timing, the
value of the counter. Reading the timer Ai register with the reload timing gets “FFFF
16
”. Reading the
timer Ai register after setting a value in the timer Ai register with a count halted but before the counter
starts counting gets a proper value.
(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 TAi
OUT
pin outputs “L” level.
The interrupt request generated and the timer Ai interrupt request bit goes to “1”.
(2) The timer Ai 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 Ai interrupt (interrupt request bit), set timer Ai interrupt request bit to “0”
after the above listed changes have been made.
Timer A (one-shot timer mode)
(1) The timer Ai interrupt request bit becomes “1” if setting operation mode of the timer in compliance with
any of the following procedures:
Selecting PWM mode after reset.
Changing operation mode from timer mode to PWM mode.
Changing operation mode from event counter mode to PWM mode.
Therefore, to use timer Ai interrupt (interrupt request bit), set timer Ai interrupt request bit to “0”
after the above listed changes have been made.
(2) Setting the count start flag to “0” while PWM pulses are being output causes the counter to stop
counting. If the TAi
OUT
pin is outputting an “H” level in this instance, the output level goes to “L”, and
the timer Ai interrupt request bit goes to “1”. If the TAi
OUT
pin is outputting an “L” level in this instance,
the level does not change, and the timer Ai interrupt request bit does not becomes “1”.
Timer A (pulse width modulation mode)
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.