MPC555 / MPC556
TPU ROM FUNCTIONS
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
D-22
D.10 Multichannel Pulse-Width Modulation (MCPWM)
MCPWM generates pulse-width modulated outputs with full 0% to 100% duty cycle
range independent of other TPU activity. This capability requires two TPU channels
plus an external gate for one PWM channel. (A simple one-channel PWM capability is
supported by the QOM function.)
Multiple PWMs generated by MCPWM have two types of high time alignment: edge
aligned and center aligned. Edge-aligned mode uses n + 1 TPU channels for n PWMs;
center-aligned mode uses 2n + 1 channels. Center-aligned mode allows a user-de-
fined “dead time” to be specified so that two PWMs can be used to drive an H-bridge
without destructive current spikes. This feature is important for motor control applica-
tions. See Motorola TPU Progamming Note
Multichannel PWM TPU Function
(MCPWM),
(TPUPN05/D)
.
through
show the host interface areas for the MCPWM func-
tion in each mode.
F
re
e
sc
a
le
S
e
m
ic
o
n
d
u
c
to
r,
I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
n
c
.
..