Introduction
1479
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
64-Bit Timer Plus
30.1.5.4.2.2.4 32-Bit Timer Unchained Mode Configuration Procedure
To configure timer 1:2, follow the steps below:
1. Select 32-bit unchained mode (TIMMODE in TGCR).
2. Remove the timer 1:2 from reset (TIM12RS in TGCR).
3. Select the desired timer period for timer 1:2 (PRD12). Program with the desired timer period value - 1.
4. Select the desired clock source for timer 1:2 (CLKSRC12 in TCR).
5. Enable timer 1:2 (ENAMODE12 in TCR).
6. If ENAMODE12 = 3h, write the desired timer period for the next timer cycle in the period reload register
(REL12). Program with the desired timer period value - 1. This step can be done at any time before the
current timer cycle ends.
To configure timer 3:4, follow the steps below:
1. Select 32-bit unchained mode (TIMMODE in TGCR).
2. Remove the timer 3:4 from reset (TIM34RS in TGCR).
3. Select the desired timer period for timer 3:4 (PRD34). Program with the desired timer period value - 1.
4. Select the desired prescaler value for timer 3:4 (PSC34 in TGCR).
5. Enable timer 3:4 (ENAMODE34 in TCR).
6. If ENAMODE34 = 3h, write the desired timer period for the next timer cycle in the period reload register
(REL34). Program with the desired timer period value - 1. This step can be done at any time before the
current timer cycle ends.
30.1.5.4.2.2.5 Event Capture Mode
When the PLUSEN bit in the timer global control register (TGCR) is set, Event Capture Mode is available
for TIM12 when the timer is configured in 32-bit unchained mode. When Event Capture Mode is enabled,
the timer cycle is restarted when an external input event occurs on pin TM64P_IN12. In particular, when
an external input event occurs, the timer stops counting, generates output events (TINT12, TEVT12, and
TM64P_OUT12), copies values from the timer counter register TIM12 to the timer capture register CAP12,
reloads the timer period register PRD12 if in continuous mode with period reload (ENAMODE = 3h), and
then restarts counting in continuous mode. Event Capture Mode is available only when the timer clock
source is the internal timer (CLKSRC = 0) and the timer is in continuous mode (ENAMODE = 2h or 3h).
Capture mode is enabled using the Capture mode enable bit CAPMODE12 in the timer control register
(TCR). The type of input event is selected by the capture event mode bit CAPEVTMODE12 in the timer
control register (TCR). All of the following input event types are available:
•
Rising edge of input signal
•
Falling edge of input signal
•
Rising or falling edge of input signal
30.1.5.4.2.2.6 Timer Counter Register Read Reset Mode
Read Reset Mode is available when the PLUSEN bit in the timer global control register (TGCR) is set and
the timer is configured in 32-bit unchained mode. When Read Reset Mode is enabled, the timer cycle will
restart when the timer counter registers are read (TIM12 and/or TIM34). In particular, when the timer
registers are read, the timer stops counting, copies values from the timer counter registers (TIM12 and/or
TIM34) to the timer capture registers (CAP12 and/or CAP34), reloads the timer period registers (PRD12
and/or PRD34) if in continuous mode with period reload (ENAMODE = 3h), and then restarts counting in
continuous mode. Timer output events (TINT
n
, TEVT
n
, and TM64P_OUT
n
) are not generated during this
process. Read Reset Mode is enabled using the read reset mode enable bit (READRSTMODE) in the
timer control register (TCR).