MC9S12E256 Datasheet, PDF (342/602 Pages) Freescale Semiconductor, Inc – HCS12 Microcontrollers

Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
11.3.2.21 PMF Frequency Control A Register (PMFFQCA)
Module Base + 0x0021
7
R
W
Reset
0
6
5
LDFQA
4
3
2
1
HALFA
PRSCA
0
0
0
0
0
0
Figure 11-27. PMF Frequency Control A Register (PMFFQCA)
0
PWMRFA
0
Read and write anytime.
Table 11-26. PMFFQCA Field Descriptions
Field
Description
7–4
LDFQA
3
HALFA
2–1
PRSCA
0
PWMRFA
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.
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
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.
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.
LDFQA
0000
0001
0010
0011
0100
0101
0110
0111
Table 11-27. PWM Reload Frequency A
PWM Reload Frequency
Every PWM opportunity
Every 2 PWM opportunities
Every 3 PWM opportunities
Every 4 PWM opportunities
Every 5 PWM opportunities
Every 6 PWM opportunities
Every 7 PWM opportunities
Every 8 PWM opportunities
LDFQ[3:0]
1000
1001
1010
1011
1100
1101
1110
1111
PWM Reload Frequency
Every 9 PWM opportunities
Every 10 PWM opportunities
Every 11 PWM opportunities
Every 12 PWM opportunities
Every 13 PWM opportunities
Every 14 PWM opportunities
Every 15 PWM opportunities
Every 16 PWM opportunities
MC9S12E256 Data Sheet, Rev. 1.08
342
Freescale Semiconductor