RL78/G13 CHAPTER 6 TIMER ARRAY UNIT
R01UH0146EJ0100 Rev.1.00 380
Sep 22, 2011
6.7 Independent Channel Operation Function of Timer Array Unit
6.7.1 Operation as interval timer/square wave output
(1) Interval timer
The timer array unit can be used as a reference timer that generates INTTMmn (timer interrupt) at fixed intervals.
The interrupt generation period can be calculated by the following expression.
Generation period of INTTMmn (timer interrupt) = Period of count clock × (Set value of TDRmn + 1)
(2) Operation as square wave output
TOmn performs a toggle operation as soon as INTTMmn has been generated, and outputs a square wave with a
duty factor of 50%.
The period and frequency for outputting a square wave from TOmn can be calculated by the following expressions.
• Period of square wave output from TOmn = Period of count clock × (Set value of TDRmn + 1) × 2
• Frequency of square wave output from TOmn = Frequency of count clock/{(Set value of TDRmn + 1) × 2}
Timer count register mn (TCRmn) operates as a down counter in the interval timer mode.
The TCRmn register loads the value of timer data register mn (TDRmn) at the first count clock after the channel
start trigger bit (TSmn, TSHm1, TSHm3) of timer channel start register m (TSm) is set to 1. If the MDmn0 bit of
timer mode register mn (TMRmn) is 0 at this time, INTTMmn is not output and TOmn is not toggled. If the MDmn0
bit of the TMRmn register is 1, INTTMmn is output and TOmn is toggled.
After that, the TCRmn register count down in synchronization with the count clock.
When TCRmn = 0000H, INTTMmn is output and TOmn is toggled at the next count clock. At the same time, the
TCRmn register loads the value of the TDRmn register again. After that, the same operation is repeated.
The TDRmn register can be rewritten at any time. The new value of the TDRmn register becomes valid from the
next period.
Remark m: Unit number (m = 0, 1), n: Channel number (n = 0 to 7)
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