MC68HC908MR8 Datasheet, PDF (155/372 Pages) Motorola, Inc – Microcontrollers

OUTPUT CONTROL
(OUTCTL)
OUT2
OUT4
OUT6
Pulse-Width Modulator for Motor Control (PWMMC)
Output Control
PWMPAIR12
(TOP)
MUMXUX
PWM((TTOOPP))
PRPERDETD(T(OTPO)P)
OUTX
SELECT
DEAD-TIME
POSTDT (TOP)
MUX
PWMPAIR34
PWM (TOP)
6
(TOP)
DEAD-TIME
PREDT (TOP)
POSTDT (TOP)
OUTX
SELECT
TOP
(PWM1)
BOTTOM
(PWM2)
TOP
(PWM3)
BOTTOM
(PWM4)
PWM1
PWM2
PWM3
PWM4
PWMPAIR56
(TOP)
MUX
PWM (TOP)
PREDT (TOP)
OUTX
SELECT
DEAD-TIME
POSTDT (TOP)
TOP
(PWM5)
BOTTOM
(PWM6)
PWM5
PWM6
Figure 9-13. Dead-Time Generators
Whenever an input to a dead-time generator transitions, a dead-time is
inserted (for example, both PWMs in the pair are forced to their inactive
state). The BOTTOM PWM signal is generated from the TOP PWM and
the dead-time. In the case of output control enabled, the odd OUTx bits
control the top PWMs, the even OUTx bits control the bottom PWMs with
respect to the odd OUTx bits (see Table 9-4). Figure 9-14 shows the
effects of the dead-time insertion.
Examples of dead-time insertion are shown in Figure 9-14 through
Figure 9-16. Figure 9-15 shows the effects of dead-time insertion at the
duty cycle boundaries (near 0% and 100% duty cycles). Figure 9-16
shows the effects of dead-time insertion on pulse widths smaller than the
dead-time.
MC68HC908MR8 — Rev 4.1
Freescale Semiconductor Pulse-Width Modulator for Motor Control (PWMMC)
Technical Data
155