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Chapter 14 Pulse Width Modulator with Fault Protection (PMF15B6CV3)
MC9S12ZVM Family Reference Manual Rev. 1.3
512
Freescale Semiconductor
Table 14-25. PMFFQCA Field Descriptions
Field
Description
7–4
LDFQA[3:0]
Load Frequency A — This field selects the PWM load frequency according to
. See
Section 14.4.12.3, “Load Frequency”
for more details.
Note: The LDFQA field takes effect when the current load cycle is complete, regardless of the state of the
LDOKA bit or global load OK. Reading the LDFQA field reads the buffered value and not necessarily the
value currently in effect.
3
HALFA
Half Cycle Reload A — This bit enables half-cycle reloads in center-aligned PWM mode. This bit has no effect
on edge-aligned PWMs. It takes effect immediately. When set, reload opportunities occur also when the counter
matches the modulus in addition to the start of the PWM period at count zero. See
for more details.
0 Half-cycle reloads disabled
1 Half-cycle reloads enabled
2–1
PRSCA[1:0]
Prescaler A — This buffered field selects the PWM clock frequency illustrated in
Note: Reading the PRSCA field reads the buffered value and not necessarily the value currently in effect. The
PRSCA field takes effect at the beginning of the next PWM cycle and only when the LDOKA bit or global
load OK is set.
0
PWMRFA
PWM Reload Flag A — This flag is set at the beginning of every reload cycle regardless of the state of the
LDOKA bit or global load OK. Clear PWMRFA by reading PMFFQCA with PWMRFA set and then writing a logic
one to the PWMRFA bit. If another reload occurs before the clearing sequence is complete, writing logic one to
PWMRFA has no effect.
0 No new reload cycle since last PWMRFA clearing
1 New reload cycle since last PWMRFA clearing
Note: Clearing PWMRFA satisfies pending PWMRFA CPU interrupt requests.
Table 14-26. PWM Reload Frequency A
LDFQA[3:0]
PWM Reload Frequency
LDFQ[3:0]
PWM Reload Frequency
0000
Every PWM opportunity
1000
Every 9 PWM opportunities
0001
Every 2 PWM opportunities
1001
Every 10 PWM opportunities
0010
Every 3 PWM opportunities
1010
Every 11 PWM opportunities
0011
Every 4 PWM opportunities
1011
Every 12 PWM opportunities
0100
Every 5 PWM opportunities
1100
Every 13 PWM opportunities
0101
Every 6 PWM opportunities
1101
Every 14 PWM opportunities
0110
Every 7 PWM opportunities
1110
Every 15 PWM opportunities
0111
Every 8 PWM opportunities
1111
Every 16 PWM opportunities
Table 14-27. PWM Prescaler A
PRSCA[1:0]
Prescaler Value P
A
PWM Clock Frequency f
PWM_A
00
1
f
core
01
2
f
core
/2
10
4
f
core
/4
11
8
f
core
/8