REGISTER SUMMARY
M68HC16 Z SERIES
D-76
USER’S MANUAL
F1A/B — Force Logic Level One on PWMA/B
0 = Force logic level zero output on PWMA/B pin.
1 = Force logic level one output on PWMA/B pin.
D.8.15 PWM Registers A/B
PWMA — PWM Register A
$YFF926
PWMB — PWM Register B
$YFF927
The value in these registers determines pulse width of the corresponding PWM output.
A value of $00 corresponds to continuously low output; a value of $80 to 50% duty cy-
cle. Maximum value ($FF) selects an output that is high for 255/256 of the period.
Writes to these registers are buffered by PWMBUFA and PWMBUFB.
D.8.16 PWM Count Register
PWMCNT — PWM Count Register
$YFF928
PWMCNT is the 16-bit free-running counter used for GPT PWM functions.
D.8.17 PWM Buffer Registers A/B
PWMBUFA — PWM Buffer Register A
$YFF92A
PWMBUFB — PWM Buffer Register B
$YFF92B
To prevent glitches when PWM duty cycle is changed, the contents of PWMA and
PWMB are transferred to these read-only registers at the end of each duty cycle. Re-
set state is $0000.
Table D-50 PWM Frequency Ranges
PPR
[2:0]
Prescaler Tap
SFA/B = 0
SFA/B = 1
16.78 MHz
20.97 MHz
25.17 MHz
16.78
MHz
20.97
MHz
25.17
MHz
16.78 MHz
20.97 MHz
25.17 MHz
000
Div 2 = 8.39 MHz
Div 2 = 10.5 MHz
Div 2 = 12.6 MHz
32.8 kHz
41 kHz
49.2 kHz
256 Hz
320 Hz
384 Hz
001
Div 4 = 4.19 MHz
Div 4 = 5.25 MHz
Div 4 = 6.29 MHz
16.4 kHz
20.5 kHz
24.6 kHz
128 Hz
160 Hz
192 Hz
010
Div 8 = 2.10 MHz
Div 8 = 2.62 MHz
Div 8 = 3.15 MHz
8.19 kHz
10.2 kHz
12.3 kHz
64.0 Hz
80.0 Hz
96 Hz
011
Div 16 = 1.05 MHz
Div 16 = 1.31 MHz
Div 16 = 1.57 MHz
4.09 kHz
5.15 kHz
6.13 kHz
32.0 Hz
40.0 Hz
48 Hz
100
Div 32 = 524 kHz
Div 32 = 655 kHz
Div 32 = 787 kHz
2.05 kHz
2.56 kHz
3.07 kHz
16.0 Hz
20.0 Hz
24 Hz
101
Div 64 = 262 kHz
Div 64 = 328 kHz
Div 64 = 393 kHz
1.02 kHz
1.28 kHz
1.54 kHz
8.0 Hz
10.0 Hz
12 Hz
110
Div 128 = 131 kHz
Div 128 = 164 kHz
Div 128 = 197 kHz
512 Hz
641 Hz
770 Hz
4.0 Hz
5.0 Hz
6 Hz
111
PCLK
PCLK
PCLK
PCLK/256
PCLK/256
PCLK/256
PCLK/32768
PCLK/32768
PCLK/32768
F
re
e
sc
a
le
S
e
m
ic
o
n
d
u
c
to
r,
I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
n
c
.
..