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Chapter 14 Pulse Width Modulator with Fault Protection (PMF15B6CV3)
MC9S12ZVM Family Reference Manual Rev. 1.3
Freescale Semiconductor
515
14.3.2.25 PMF Frequency Control B Register (PMFFQCB)
Address: Module Base + 0x0029
Access: User read/write
(1)
1. Read: Anytime. Returns zero if MTG is clear.
Write: Anytime if MTG is set.
7
6
5
4
3
2
1
0
R
LDFQB
HALFB
PRSCB
PWMRFB
W
Reset
0
0
0
0
0
0
0
0
Figure 14-30. PMF Frequency Control B Register (PMFFQCB)
Table 14-29. PMFFQCB Field Descriptions
Field
Description
7–4
LDFQB[3:0]
Load Frequency B — This field selects the PWM load frequency according to
. See
Section 14.4.12.3, “Load Frequency”
for more details.
Note: The LDFQB field takes effect when the current load cycle is complete, regardless of the state of the
LDOKB bit or global load OK. Reading the LDFQB field reads the buffered value and not necessarily the
value currently in effect.
3
HALFB
Half Cycle Reload B — 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
PRSCB[1:0]
Prescaler B — This buffered field selects the PWM clock frequency illustrated in
Note: Reading the PRSCB field reads the buffered value and not necessarily the value currently in effect. The
PRSCB field takes effect at the beginning of the next PWM cycle and only when the LDOKB bit or global
load OK is set.
0
PWMRFB
PWM Reload Flag B — This flag is set at the beginning of every reload cycle regardless of the state of the
LDOKB bit. Clear PWMRFB by reading PMFFQCB with PWMRFB set and then writing a logic one to the
PWMRFB bit. If another reload occurs before the clearing sequence is complete, writing logic one to PWMRFB
has no effect.
0 No new reload cycle since last PWMRFB clearing
1 New reload cycle since last PWMRFB clearing
Note: Clearing PWMRFB satisfies pending PWMRFB CPU interrupt requests.
Table 14-30. PWM Reload Frequency B
LDFQB[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