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Pulse-Width Modulation (PWM) Module
Freescale Semiconductor
29-10
MCF52235 ColdFire® Integrated Microcontroller Reference Manual, Rev. 6
(PWME
n
=0), the PWMCNT
n
register does not count. When a channel is enabled (PWME
n
=1), the
associated PWM counter starts at the count in the PWMCNT
n
register. For more detailed information on
the operation of the counters, refer to
Section 29.3.2.4, “PWM Timer Counters.”
29.2.10 PWM Channel Period Registers (PWMPERn)
The PWM period registers determine the period of the associated PWM channel. Refer to
for more information.
Calculating the output period depends on the output mode (center-aligned has twice the period as
left-aligned mode) as well as PWMPER
n
. See the below equation:
Eqn. 29-3
For boundary case programming values (e.g. PWMPER
n
= 0x00), please refer to
.
IPSBAR
Offset:
0x1B_000C (PWMCNT0)
0x1B_000D (PWMCNT1)
0x1B_000E (PWMCNT2)
0x1B_000F (PWMCNT3)
0x1B_0010 (PWMCNT4)
0x1B_0011 (PWMCNT5)
0x1B_0012 (PWMCNT6)
0x1B_0013 (PWMCNT7)
Access:
SupervisorRead/Write
7
6
5
4
3
2
1
0
R
COUNT
W
Reset:
0
0
0
0
0
0
0
0
Figure 29-10. PWM Counter Registers (PWMCNTn)
Table 29-10. PWMCNTn Field Descriptions
Field
Description
7–0
COUNT
Current value of the PWM up counter. Resets to zero when written.
PWM
n
period
Channel clock period
PWMCAE CAE
n
[
]
1
+
(
)
PWMPER
n
×
×
=
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:MCF52234CVM60,
MCF52235CVM60