M16C80 Datasheet, PDF (220/358 Pages) Renesas Technology Corp – RENESAS 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/80 SERIES

M16C/80 Group
27. Usage Precaution
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 output from the one-shot timer synchronizes with the count source generated internally. There-
fore, when an external trigger has been selected, a delay of one cycle of count source as maximum
occurs between the trigger input to the TAiIN pin and the one-shot timer output.
(3) 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.
(4) If a trigger occurs while a count is in progress, after the counter performs one down count following the
reoccurrence of a trigger, the reload register contents are reloaded, and the count continues. To
generate a trigger while a count is in progress, generate the second trigger after an elapse longer than
one cycle of the timer's count source after the previous trigger occurred.
(5) If an external trigger input is used to start counting, the next external trigger input must be avoided
within 300ns before the timer A reaches "0000h".
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 Aug. 02, 2005 ^{Page 209} of 329
REJ09B0187-0100