timer_clock
pi_eventcapt
eventcapt_resync
capt_pulse
int_serve
clear_trig
FSM State
tcar1_enable
TCRR
TCAR1
TCAR2
OCKED
LOCKED1
NEW_VALUE
Capture ignored
Capture ignored
NEW_VALUE
UN-LOCKED
LOCKED2
LOCKED1
UN-LO
LOCKED2
tcar2_enable
NEW_VALUE
NEW_VALUE
DMTimer
Figure 20-6. Capture Wave Example for CAPT_MODE = 1
20.1.3.1.3 Compare Mode Functionality
When Compare Enable TCLR (CE bit) is set to 1, the timer value (TCRR) is permanently compared to the
value held in timer match register (TMAR). TMAR value can be loaded at any time (timer counting or
stop). When the TCRR and the TMAR values match, an interrupt can be issued if the IRQENABLE_SET
(MAT_EN_FLAG bit) is set. The right programming way is to write a compare value in TMAR register
before setting TCLR (CE bit) to avoid any unwanted interrupt due to a reset value matching effect.
The dedicated output pin (PORTIMERPWM) can be programmed through TCLR (TRG and PT bits) to
generate one positive pulse (TIMER clock duration) or to invert the current value (toggle mode) when an
overflow and a match occur.
20.1.3.1.4 Prescaler Functionality
A prescaler counter can be used to divide the timer counter input clock frequency. The prescaler is
enabled when TCLR bit 5 is set (PRE). The 2n division ratio value (PTV) can be configured in the TCLR
register. The prescaler counter is reset when the timer counter is stopped or reloaded on the fly.
Table 20-6. Prescaler Functionality
Contexts
Prescaler Counter
Timer Counter
Overflow (when Auto-reload on)
Reset
TLDR
TCRR Write
Reset
TCRR
TTGR Write
Reset
TLDR
Stop
Reset
Frozen
3559
SPRUH73H – October 2011 – Revised April 2013
Timers
Copyright © 2011–2013, Texas Instruments Incorporated