CC2430 Datasheet, PDF(101/234 Page) Texas Instruments – A True System-on-Chip solution for 2.4 GHz IEEE 802.15.4 / ZigBee-TM

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CC2430 Datasheet, PDF (101/234 Pages) Texas Instruments – A True System-on-Chip solution for 2.4 GHz IEEE 802.15.4 / ZigBee-TM

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CC2430

and T1CTL.CH2IF for channel 2. An interrupt

request is generated if the corresponding

interrupt mask bit on T1CCTL0.IM,

T1CCTL1.IM, or T1CCTL2.IM, respectively,

is set.

Examples of output compare modes in various

timer modes are given in the following figures.

Edge-aligned PWM output signals can be

generated using the timer modulo mode and

channels 1 and 2 in output compare mode 6 or

7 as shown in Figure 23. The period of the

PWM signal is determined by the setting

T1CC0 and the duty cycle for the channel

output is determined by T1CCn. The timer free-

running mode may also be used. In this case

CLKCON.TICKSPD and the prescaler divider

value T1CTL.DIV set the period of the PWM

signal. The polarity of the PWM signal is

determined by whether output compare mode

6 or 7 is used. PWM output signals can also

be generated using output compare modes 4

and 5 as shown in the same figure, or by using

modulo mode as shown in Figure 24. Using

output compare mode 4 and 5 is preferred for

simple PWM.

Centre-aligned PWM outputs can be

generated when the timer up/down mode is

selected. The channel output compare mode 4

or 5 is selected depending on required polarity

of the PWM signal. The period of the PWM

signal is determined by T1CC0 and the duty

cycle for the channel output is determined by

T1CCn.

The centre-aligned PWM mode is required by

certain types of motor drive applications and

typically less noise is produced than the edge-

aligned PWM mode because the I/O pin

transitions are not lined up on the same clock

edge.

In some types of applications, a defined delay

or dead time is required between outputs.

Typically this is required for outputs driving an

H-bridge configuration to avoid uncontrolled

cross-conduction in one side of the H-bridge.

The delay or dead-time can be obtained in the

PWM outputs by using T1CCn as shown in the

following:

Assuming that channel 1 and channel 2 are

used to drive the outputs using timer up/down

mode and the channels use output compare

modes 4 and 5 respectively, then the timer

period (in Timer 1 clock periods) is:

TP = T1CC0 x 2

and the dead time, i.e. the time when both

outputs are low, (in Timer 1 clock periods) is

given by:

TD = T1CC1 â T1CC2

CC2430 PRELIMINARY Data Sheet (rev. 1.03) SWRS036A

Page 101 of 232

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