SAM7X256_14 Datasheet, PDF (379/662 Pages) ATMEL Corporation – ARM-based Flash MCU

32.5.4 Clock Control
The clock of each counter can be controlled in two different ways: it can be enabled/disabled and started/stopped. See
Figure 32-4.
 The clock can be enabled or disabled by the user with the CLKEN and the CLKDIS commands in the Control
Register. In Capture Mode it can be disabled by an RB load event if LDBDIS is set to 1 in TC_CMR. In Waveform
Mode, it can be disabled by an RC Compare event if CPCDIS is set to 1 in TC_CMR. When disabled, the start or the
stop actions have no effect: only a CLKEN command in the Control Register can re-enable the clock. When the clock
is enabled, the CLKSTA bit is set in the Status Register.
 The clock can also be started or stopped: a trigger (software, synchro, external or compare) always starts the clock.
The clock can be stopped by an RB load event in Capture Mode (LDBSTOP = 1 in TC_CMR) or a RC compare event
in Waveform Mode (CPCSTOP = 1 in TC_CMR). The start and the stop commands have effect only if the clock is
enabled.
Figure 32-4. Clock Control
Selected
Clock
Trigger
Q
S
R
CLKSTA CLKEN CLKDIS
Q
S
R
Counter
Clock
Stop Disable
Event Event
32.5.5 TC Operating Modes
Each channel can independently operate in two different modes:
 Capture Mode provides measurement on signals.
 Waveform Mode provides wave generation.
The TC Operating Mode is programmed with the WAVE bit in the TC Channel Mode Register.
In Capture Mode, TIOA and TIOB are configured as inputs.
In Waveform Mode, TIOA is always configured to be an output and TIOB is an output if it is not selected to be the
external trigger.
32.5.6 Trigger
A trigger resets the counter and starts the counter clock. Three types of triggers are common to both modes, and a fourth
external trigger is available to each mode.
The following triggers are common to both modes:
SAM7X Series [DATASHEET]
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