Pulse-Width Modulation (PWM) Module
29-11
Freescale Semiconductor
MCF52235 ColdFire® Integrated Microcontroller Reference Manual, Rev. 6
29.2.11 PWM Channel Duty Registers (PWMDTYn)
The PWM duty registers determine the duty cycle of the associated PWM channel. To calculate the output
duty cycle (high time as a percentage of period) for a particular channel:
Eqn. 29-4
For boundary case programming values (e.g. PWMDTY
n
= 0x00 or PWMDTY
n
> PWMPER
n
), refer to
Section 29.3.2.8, “PWM Boundary Cases”
.
IPSBAR
Offset:
0x1B_0014 (PWMPER0)
0x1B_0015 (PWMPER1)
0x1B_0016 (PWMPER2)
0x1B_0017 (PWMPER3)
0x1B_0018 (PWMPER4)
0x1B_0019 (PWMPER5)
0x1B_001A (PWMPER6)
0x1B_001B (PWMPER7)
Access:
SupervisorRead/Write
7
6
5
4
3
2
1
0
R
PERIOD
W
Reset:
1
1
1
1
1
1
1
1
Figure 29-11. PWM Period Registers (PWMPERn)
Table 29-11. PWMPERn Field Descriptions
Field
Description
7–0
PERIOD
Period counter for the output PWM signal.
If PERIOD equals 0x00, the PWMn output is always high (PPOLn=1) or always low (PPOLn=0). See
Section 29.3.2.8, “PWM Boundary Cases”
for other special cases.
IPSBAR
Offset:
0x1B_001C (PWMDTY0)
0x1B_001D (PWMDTY1)
0x1B_001E (PWMDTY2)
0x1B_001F (PWMDTY3)
0x1B_0020 (PWMDTY4)
0x1B_0021 (PWMDTY5)
0x1B_0022 (PWMDTY6)
0x1B_0023 (PWMDTY7)
Access:
SupervisorRead/Write
7
6
5
4
3
2
1
0
R
DUTY
W
Reset:
1
1
1
1
1
1
1
1
Figure 29-12. PWM Duty Registers (PWMDTYn)
Duty Cycle
1
PWMPOL PPOL
n
[
]
PWMDTY
n
PWMPER
n
------------------------------
–
–
⎝
⎠
⎛
⎞
100%
×
=
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