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M
1
6
C
2 /
6
A
G
o r
u
p
(
M
1
6
12.1.4. Pulse Width Modulation (PWM) Mode
In PWM mode, the timer outputs pulses of a given width in succession (see Table 12.1.4.1). The counter
functions as either 16-bit pulse width modulator or 8-bit pulse width modulator. Figure 12.1.4.1 shows
TAiMR register in pulse width modulation mode. Figures 12.1.4.2 and 12.1.4.3 show examples of how a
16-bit pulse width modulator operates and how an 8-bit pulse width modulator operates.
Table 12.1.4.1. Specifications in Pulse Width Modulation Mode
Item
Count source
Count operation
16-bit PWM
8-bit PWM
Count start condition
Count stop condition
Interrupt request generation timing
TAi
pin function
IN
TAi
pin function
OUT
Read from timer
Write to timer
R
e
. v
2
0 .
0
F
e
b
1 .
, 5
2
0
0
7
R
E
J
0
9
B
0
2
0
2
0 -
2
0
0
C
2 /
6
, A
M
1
6
C
2 /
6
, B
M
1
6
f
, f
, f
, f
, f
1
2
8
32
C32
• Down-count (operating as an 8-bit or a 16-bit pulse width modulator)
• The timer reloads a new value at a rising edge of PWM pulse and continues counting
• The timer is not affected by a trigger that occurs during counting
• High level width
• Cycle time (2
• High level width n x (m+1) / fj n : set value of TAi register high-order address
• Cycle time
(2
• TAiS bit in theTABSR register is set to "1" (= start counting)
• The TAiS bit is set to "1" and external trigger input from the TAi
• The TAiS bit is set to "1" and one of the following external triggers occurs
Timer B2 overflow or underflow,
timer Aj (j=i-1, except j=4 if i=0) overflow or underflow,
timer Ak (k=i+1, except k=0 if i=4) overflow or underflow
TAiS bit is set to "0" (= stop counting)
PWM pulse goes "L"
I/O port or trigger input
Pulse output
An indeterminate value is read by reading TAi register
• When not counting and until the 1st count source is input after counting start
Value written to TAi register is written to both reload register and counter
• When counting (after 1st count source input)
Value written to TAi register is written to only reload register
(Transferred to counter when reloaded next)
page 105
f o
3
2
9
C
2 /
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) T
Specification
n / fj
n : set value of TAi register (i=o to 4)
16
-1) / fj fixed
fj: count source frequency (f
8
-1) x (m+1) / fj m : set value of TAi register low-order address
12. Timer
, f
, f
, f
, f
)
1
2
8
32
C32
pin
IN
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