P89LPC9321 NXP Semiconductors, P89LPC9321 Datasheet - Page 34

• Manufacturer Part Number: P89LPC9321
• Description: The P89LPC9321 is a single-chip microcontroller, available in low cost packages, basedon a high performance processor architecture that executes instructions in two to fourclocks, six times the rate of standard 80C51 devices
• Manufacturer: NXP Semiconductors

NXP Semiconductors
P89LPC9321
Product data sheet
7.22.7 Alternating output mode
7.22.8 PLL operation
In asymmetrical mode, the user can set up PWM channels A/B and C/D as alternating
pairs for bridge drive control. In this mode the output of these PWM channels are
alternately gated on every counter cycle.
The PWM module features a Phase Locked Loop that can be used to generate a
CCUCLK frequency between 16 MHz and 32 MHz. At this frequency the PWM module
provides ultrasonic PWM frequency with 10-bit resolution provided that the crystal
frequency is 1 MHz or higher. The PLL is fed an input signal from 0.5 MHz to 1 MHz and
generates an output signal of 32 times the input frequency. This signal is used to clock the
timer. The user will have to set a divider that scales PCLK by a factor from 1 to 16. This
divider is found in the SFR register TCR21. The PLL frequency can be expressed as
shown in
Where: N is the value of PLLDV3:0.
PLL frequency
Fig 9.
Fig 10. Alternate output mode
Symmetrical PWM
Equation
compare value
=
All information provided in this document is subject to legal disclaimers.
non-inverted
timer value
----------------- -
(
PCLK
N
inverted
1:
TOR2
+
Rev. 2 — 16 November 2010
1
)
0
8-bit microcontroller with accelerated two-clock 80C51 core
002aaa895
TOR2
COMPARE VALUE A (or C)
COMPARE VALUE B (or D)
0
PWM OUTPUT (OCA or OCC)
PWM OUTPUT (OCB or OCD)
TIMER VALUE
P89LPC9321
002aaa894
© NXP B.V. 2010. All rights reserved.
34 of 71
(1)