Chapter 25 FlexPWM
MPC5602P Microcontroller Reference Manual, Rev. 4
Freescale Semiconductor
653
25.5
External signal descriptions
The PWM module has external pins named PWMA[
n
], PWMB[
n
], PWMX[
n
], FAULT[
n
], EXT_SYNC.
The PWM module also has on-chip inputs called EXT_CLK, EXT_FORCE and on-chip outputs called
OUT_TRIG[
n
].
25.5.1
PWMA[
n
] and PWMB[
n
] — external PWM pair
These pins are the output pins of the PWM channels. They can be independent PWM signals or a
complementary pair.
25.5.2
PWMX[
n
] — auxiliary PWM signal
These pins are the auxiliary output pins of the PWM channels. They can be independent PWM signals.
When not needed as an output, they can be used to generate the IPOL bit during deadtime correction.
25.5.3
FAULT[
n
] — fault inputs
These are input pins for disabling selected PWM outputs.
25.5.4
EXT_SYNC — external synchronization signal
This input signal allows a source external to the PWM to initialize the PWM counter. In this manner the
PWM can be synchronized to external circuitry.
25.5.5
EXT_FORCE — external output force signal
This input signal allows a source external to the PWM to force an update of the PWM outputs. In this
manner the PWM can be synchronized to external circuitry. An example would be to simultaneously
switch all of the PWM outputs on a commutation boundary for trapezoidal control of a BLDC motor. The
source of EXT_FORCE signal is eTimer_0 OFLAG.
25.5.6
OUT_TRIG0[n] and OUT_TRIG1[n] — output triggers
These outputs allow the PWM submodules to control timing of the ADC conversions. See
Section 25.6.3.15, “Output Trigger Control register (TCTRL)
for a description of how to enable these
outputs and how the compare registers match up to the output triggers.
25.5.7
EXT_CLK — external clock signal
This on-chip input signal allows an on-chip source external to the PWM (typically a Timer) to control the
PWM clocking. In this manner the PWM can be synchronized to the Timer. This signal must be generated
synchronously to the PWM’s clock since it is not resynchronized in the PWM.