PXS20RM Datasheet, PDF (679/1368 Pages) Freescale Semiconductor, Inc – PXS20 Microcontroller

Flexible Motor Control Pulse Width Modulator Module (FlexPWM)
Counter
Reload
Change
Reload ^{Every two}
Frequency ^{opportunities}
to every four
opportunities
to every
opportunity
Figure 25-32. Half Cycle Reload Frequency Change
Counter
Reload
Change
Reload ^{Every two}
Frequency ^{opportunities}
to every four
opportunities
to every to every two
opportunity opportunities
Figure 25-33. Full and Half Cycle Reload Frequency Change
25.3.4.3 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.
READ RF AS 1 THEN
WRITE 0 TO RF
RESET
PWM RELOAD
V_DD
RF
D ^CLR Q
CLK
RIE
CPU INTERRUPT
REQUEST
Figure 25-34. PWMF Reload Interrupt Request
Freescale Semiconductor
PXS20 Microcontroller Reference Manual, Rev. 1
25-33