Datasheet

Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
MC9S12E128 Data Sheet, Rev. 1.07
346 Freescale Semiconductor
11.3.2.21 PMF Frequency Control A Register (PMFFQCA)
Read and write anytime.
Module Base + 0x0021
76543210
R
LDFQA HALFA PRSCA PWMRFA
W
Reset 0 0 0 00000
Figure 11-27. PMF Frequency Control A Register (PMFFQCA)
Table 11-26. PMFFQCA Field Descriptions
Field Description
7–4
LDFQA
Load Frequency A — This field selects the PWM load frequency according to Table 11-27. See
Section 11.4.7.2, “Load Frequency” for more details.
Note: The LDFQA field takes effect when the current load cycle is complete, regardless of the state of the load
okay bit, LDOKA. 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.
0 Half-cycle reloads disabled
1 Half-cycle reloads enabled
2–1
PRSCA
Prescaler A — This buffered field selects the PWM clock frequency illustrated in Table 11-28.
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 load okay bit, LDOKA,
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. 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 11-27. PWM Reload Frequency A
LDFQA 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