CC2430 Datasheet, PDF (99/234 Pages) Texas Instruments – A True System-on-Chip solution for 2.4 GHz IEEE 802.15.4 / ZigBee-TM

CC2430
FFFFh
0000h
OVFL
OVFL
Figure 20: Free-running mode
13.3.4 Modulo Mode
When the timer operates in modulo mode the
16-bit counter starts at 0x0000 and increments
at each active clock edge. When the counter
reaches the terminal count value held in
registers T1CC0H:T1CC0L, the counter is
reset to 0x0000 and continues to increment.
The flag T1CTL.OVFIF is set when the
terminal count value is reached. An interrupt
request is generated if the corresponding
interrupt mask bit TIMIF.OVFIM is set. The
modulo mode can be used for applications
where a period other then 0xFFFF is required.
The counter operation is shown in Figure 21.
T1CC0
0000h
OVFL
OVFL
Figure 21: Modulo mode
13.3.5 Up/down Mode
In the up/down timer mode, the counter
repeatedly starts from 0x0000 and counts up
until the value held in T1CC0H:T1CC0L is
reached and then the counter counts down
until 0x0000 is reached as shown in Figure 22.
This timer mode is used when symmetrical
output pulses are required with a period other
than 0xFFFF, and therefore allows
implementation of centre-aligned PWM output
applications. The flag T1CTL.OVFIF is not set
when the terminal count value is reached in
the up/down mode.
Clearing the counter by writing to T1CNTL will
also reset the count direction to the count up
from 0x0000 mode.
CC2430 PRELIMINARY Data Sheet (rev. 1.03) SWRS036A
Page 99 of 232