SAM3S8C Atmel Corporation, SAM3S8C Datasheet - Page 779

• Manufacturer Part Number: SAM3S8C
• Manufacturer: Atmel Corporation

33.6.4
33.6.5
33.6.6
11090A–ATARM–10-Feb-12
11090A–ATARM–10-Feb-12
Clock Control
TC Operating Modes
Trigger
The clock of each counter can be controlled in two different ways: it can be enabled/disabled
and started/stopped. See
•
•
Figure 33-4. Clock Control
Each channel can independently operate in two different modes:
•
•
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.
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 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.
Capture Mode provides measurement on signals.
Waveform Mode provides wave generation.
Selected
Counter
Clock
Clock
Figure
Q
33-4.
R
S
Trigger
CLKSTA
Q
CLKEN
S
R
Event
Stop
CLKDIS
SAM3S8/SD8
SAM3S8/SD8
Disable
Event
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