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CHAPTER 9 8-BIT TIMER/EVENT COUNTERS 1, 2
User’s Manual U12697EJ3V0UM
9.4.4 Operation as 8-bit PWM output
By setting bit 6 (TMC16, TMC26) of 8-bit timer mode control registers 1 and 2 (TMC1, TMC2) to 1, the timer operates
as a PWM output.
Pulses with the duty cycle determined by the value set in 8-bit compare registers 10 and 20 (CR10, CR20) is output
from TO1, TO2.
Set the width of the active level of the PWM pulse in CR10, CR20. The active level can be selected by bit 1 (TMC11,
TMC12) in TMC1, TMC2.
The count clock can be selected by bits 0 to 2 (TCLn0 to TCLn2) of prescaler mode registers 1 and 2 (PRM1,
PRM2).
The PWM output can be enabled and disabled by bit 0 (TOE1, TOE2) of TMC1, TMC2.
(1) Basic operation of the PWM output
<Setting method>
<1> Set the port latch, which also functions as timer output pin and the port mode register to 0.
<2> Set the active level width in 8-bit compare register n (CRn0).
<3> Select the count clock in prescaler mode register n (PRMn).
<4> Set the active level in bit 1 (TMCn1) of TMCn.
<5> Set bit 0 of TMCn (TOEn) to 1 to enable timer output.
<6> If bit 7 (TCEn) of TMCn is set to 1, counting starts. When counting stops, set TCEn to 0.
<PWM output operation>
<1> When counting starts, the PWM output (output from TOn) outputs the inactive level until an overflow occurs.
<2> When the overflow occurs, the active level is output. The active level is output until CRn0 and the count of 8-
bit timer counter n (TMn) match.
<3> The PWM output after CRn and the count match is the inactive level until an overflow occurs again.
<4> Steps <2> and <3> repeat until counting stops.
<5> If counting is stopped by TCEn = 0, the PWM output goes to the inactive level.
Remark
n = 1, 2
