Chapter 25 FlexPWM
MPC5602P Microcontroller Reference Manual, Rev. 4
Freescale Semiconductor
705
Figure 25-56. Full and half cycle reload frequency change
25.9.3
Reload flag
At every reload opportunity the PWM Reload Flag (RF) in the CTRL1 register is set. Setting RF happens
even if an actual reload is prevented by the LDOK bit. If the PWM reload interrupt enable bit, RIE is set,
the RF flag generates CPU interrupt requests allowing software to calculate new PWM parameters in real
time. When RIE is not set, reloads still occur at the selected reload rate without generating CPU interrupt
requests.
Figure 25-57. PWMF reload interrupt request
25.9.4
Reload errors
Whenever one of the VALx, or PSRC registers is updated, the RUF flag is set to indicate that the data is
not coherent. RUF will be cleared by a successful reload, which consists of the reload signal while LDOK
is set. If RUF is set and LDOK is clear when the reload signal occurs, a reload error has taken place and
the REF bit is set. If RUF is clear when a reload signal asserts, then the data is coherent and no error will
be flagged.
25.9.5
Initialization
Initialize all registers and set the LDOK bit before setting the RUN bit.
Counter
Reload
Change
Reload
Frequency
Every two
opportunities
to every four
opportunities
to every
opportunity
to every two
opportunities
V
DD
CPU Interrupt Request
PWM Reload
D
Q
CLK
CLR
Read RF as 1 then
Write 0 to RF
RESET
RF
RIE