M16C6K9 Datasheet, PDF (242/292 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

M16C/6K9 Group
Usage precaution
Usage Precaution
Timer A (timer mode)
(1) Reading the timer Ai register while a count is in progress allows reading, with arbitrary timing, the value of
the counter. But, reading the timer Ai register with the reload timing gets “FFFF16”. 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 setting value to the timer.
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. But, reading the timer Ai register with the reload timing gets “FFFF16” by underflow or “000016”
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 setting value to the timer.
(2) When stop counting in free run type, set timer again.
Timer A (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 TAiOUT 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 (pulse width modulation 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 TAiOUT 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 TAiOUT 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”.
Rev.1.00 Jun 06, 2003 page 242 of 290