Datasheet

713
SAM9263 [DATASHEET]
Atmel-6249N-ATARM-SAM9263-Datasheet_14-Mar-16
38.5 Product Dependencies
38.5.1 I/O Lines
The pins used for interfacing the compliant external devices may be multiplexed with PIO lines. The programmer
must first program the PIO controllers to assign the TC pins to their peripheral functions.
38.5.2 Power Management
The TC is clocked through the Power Management Controller (PMC), thus the programmer must first configure the
PMC to enable the Timer Counter clock.
38.5.3 Interrupt
The TC has an interrupt line connected to the Advanced Interrupt Controller (AIC). Handling the TC interrupt
requires programming the AIC before configuring the TC.
38.6 Functional Description
38.6.1 TC Description
The three channels of the Timer Counter are independent and identical in operation. The registers for channel
programming are listed in Table 38-4 on page 725.
38.6.2 16-bit Counter
Each channel is organized around a 16-bit counter. The value of the counter is incremented at each positive edge
of the selected clock. When the counter has reached the value 0xFFFF and passes to 0x0000, an overflow occurs
and the COVFS bit in TC_SR (Status Register) is set.
The current value of the counter is accessible in real time by reading the Counter Value Register, TC_CV. The
counter can be reset by a trigger. In this case, the counter value passes to 0x0000 on the next valid edge of the
selected clock.
38.6.3 Clock Selection
At block level, input clock signals of each channel can either be connected to the external inputs TCLK0, TCLK1 or
TCLK2, or be connected to the internal I/O signals TIOA0, TIOA1 or TIOA2 for chaining by programming the
TC_BMR (Block Mode). See Figure 38-2 on page 714.
Each channel can independently select an internal or external clock source for its counter:
 Internal clock signals: TIMER_CLOCK1, TIMER_CLOCK2, TIMER_CLOCK3, TIMER_CLOCK4,
TIMER_CLOCK5
 External clock signals: XC0, XC1 or XC2
This selection is made by the TCCLKS bits in the TC Channel Mode Register.
The selected clock can be inverted with the CLKI bit in TC_CMR. This allows counting on the opposite edges of
the clock.
The burst function allows the clock to be validated when an external signal is high. The BURST parameter in the
Mode Register defines this signal (none, XC0, XC1, XC2). See Figure 38-3 on page 714.
Note: In all cases, if an external clock is used, the duration of each of its levels must be longer than the master clock period.
The external clock frequency must be at least 2.5 times lower than the master clock