Chapter 19 Pulse-Width Modulator (S12PWM8B8CV1)
MC9S12XE-Family Reference Manual Rev. 1.19
Freescale Semiconductor
711
Figure 19-18. PWM Clock Select Block Diagram
Clock A is used as an input to an 8-bit down counter. This down counter loads a user programmable scale
value from the scale register (PWMSCLA). When the down counter reaches one, a pulse is output and the
128
2
4
8
16
32
64
PCKB2
PCKB1
PCKB0
M
U
X
Clock A
Clock B
Clock SA
Clock A/2, A/4, A/6,....A/512
Prescale
Scale
Divide b
y
PFRZ
F
reez
e Mode Signal
Bus Cloc
k
Clock Select
M
U
X
PCLK0
Clock to
PWM Ch 0
M
U
X
PCLK2
Clock to
PWM Ch 2
M
U
X
PCLK1
Clock to
PWM Ch 1
M
U
X
PCLK4
Clock to
PWM Ch 4
M
U
X
PCLK5
Clock to
PWM Ch 5
M
U
X
PCLK6
Clock to
PWM Ch 6
M
U
X
PCLK7
Clock to
PWM Ch 7
M
U
X
PCLK3
Clock to
PWM Ch 3
Load
DIV 2
PWMSCLB
Clock SB
Clock B/2, B/4, B/6,....B/512
M
U
X
PCKA2
PCKA1
PCKA0
PWME7-0
Count = 1
Load
DIV 2
PWMSCLA
Count = 1
8-Bit Down
Counter
8-Bit Down
Counter
Prescaler T
aps:
Because
of
an
order
from
the
United
States
International
Trade
Commission,
BGA-packaged
product
lines
and
part
numbers
indicated
here
currently
are
not
available
from
Freescale
for
import
or
sale
in
the
United
States
prior
to
September
2010:
S12XE
products
in
208
MAPBGA
packages
