CP3BT23_14 Datasheet, PDF (250/324 Pages) Texas Instruments – CP3BT23 Reprogrammable Connectivity Processor with Bluetooth and Dual CAN Interfaces

CP3BT23
SNOSCX3A – JULY 2013 – REVISED JANUARY 2014
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25.2.3 Mode 3: Dual Independent Timer/Counter
Mode 3 is the Dual Independent Timer mode, which generates system timing signals or counts
occurrences of external events.
Figure 25-6 is a block diagram of the Multi-Function Timer configured to operate in Mode 3. The timer is
configured to operate as a dual independent system timer or dual external event counter. In addition,
Timer/Counter 1 can generate a 50% duty cycle PWM signal on the TA pin. The TB pin can be used as an
external event input or pulse-accumulate input and can be used as the clock source for either Timer/
Counter 1 or Timer/Counter 2. Both counters can also be clocked by the prescaled System Clock.
Timer/Counter 1 (TCNT1) counts down at the rate of the selected clock. On underflow, it is reloaded from
the TCRA register and counting proceeds down from the reloaded value. In addition, the TA pin is toggled
on each underflow if this function is enabled by the TAEN bit. The initial state of the TA pin is software-
programmable. When the TA pin is toggled from low to high, it sets the TCPND interrupt pending bit and
also generates an interrupt if enabled by the TAIEN bit.
Because the TA pin toggles on every underflow, a 50% duty cycle PWM signal can be generated on the
TA pin without any further action from the CPU.
Timer/Counter 2 (TCNT2) counts down at the rate of the selected clock. On underflow, it is reloaded from
the TCRB register and counting proceeds down from the reloaded value. In addition, each underflow sets
the TDPND interrupt pending bit and generates an interrupt if the interrupt is enabled by the TDIEN bit.
Timer 1
Clock
Timer 2
Clock
Reload A
TCRA_n
Underflow
Timer/Counter 1
TCNT1_n
Reload B
TCRB_n
Underflow
Timer/Counter 2
TCNT2_n
TAPND
TAIEN
TAEN
TDIEN
TDPND
Timer
Interrupt 1
TAn
Timer
Interrupt 2
Clock
Selector
TBn
DS453
Figure 25-6. Dual-Independent Timer/Counter Mode
250 Multi-Function Timer
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