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■ 8/16-bit PPG Output Operation
In this block, the ch.0 PPG is activated to start counting when "1" is written to bit7 (PEN0) of the PPGC0
(PWM operation mode control) register. Similarly, the ch.1 PPG is activated to start counting when "1" is
written to bit15 (PEN1) of the PPGC1 register. Once the operation has started, counting is terminated by
writing "0" to bit7 (PEN0) of PPGC0 or in bit15 (PEN1) of PPGC1. Once the counting is terminated, the
output is maintained at the L level.
In 8-bit prescaler + 8-bit PPG mode, do not set ch.1 to be in operation while ch.0 operation is stopped.
In 16-bit PPG mode, ensure that bit7 (PEN0) of PPGC0 register and bit15 (PEN1) of PPGC1 register are
started or stopped simultaneously. The figure below is a diagram of PPG output operation. During PPG
operation, a pulse wave is continuously output at a frequency and duty ratio (the ratio of the "H" level
period of the pulse wave to the "L" level period). PPG continues operation until stop is specified explicitly.
PEN
Output pin
PPG
■ Relationship between 8/16-bit PPG Reload Value and Pulse Width
The width of the output pulse is determined by adding 1 to the reload register value and multiplying it by
the count clock cycle. Note that when the reload register value is "00
"0000
" during 16-bit PPG operation, the pulse width is equivalent to one count clock cycle. In addition,
H
note that when the reload register value is "FF
256 count clock cycles. When the reload register value is "FFFF
width is equivalent to 65536 count clock cycles.
Figure 16.4-1 PPG Output Operation, Output Waveform
Starts operation based on PEN (from "L" side).
T
(L+1)
T
(Start)
Pl =T
(L+1)
Ph=T
(H+1)
L : PRLL value
(H+1)
H : PRLH value
T : Input from peripheral clock (φ, φ/4, φ/16)
or time base counter (depending on th e
clock selection by PPG01)
" during 8-PPG operation, the pulse width is equivalent to
H
H
L
: PRLL value
H
: PRLH value
T
: Input clock cycle
Ph : "H" pulse width
Pl : "L" pulse width
CHAPTER 16 8/16-BIT PPG
" during 8-bit PPG operation or
H
" during 16-bit PPG operation, the pulse
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