LM3S1621_15 Datasheet, PDF (528/948 Pages) Texas Instruments – Stellaris LM3S1621 Microcontroller

General-Purpose Timers
Table 11-3. General-Purpose Timers Signals (108BGA) (continued)
Pin Name
Pin Number Pin Mux / Pin Pin Type Buffer Type^a Description
Assignment
CCP5
B3
PE5 (1)
I/O
H2
PD2 (4)
L1
PC4 (1)
C10
PG7 (8)
M7
PG5 (1)
A7
PB6 (6)
B7
PB5 (2)
TTL
Capture/Compare/PWM 5.
CCP6
G1
PD0 (6)
I/O
H2
PD2 (2)
A12
PE1 (5)
C9
PH0 (1)
B7
PB5 (3)
TTL
Capture/Compare/PWM 6.
CCP7
G2
PD1 (6)
I/O
H1
PD3 (2)
C8
PH1 (1)
A7
PB6 (2)
B4
PE3 (5)
TTL
Capture/Compare/PWM 7.
a. The TTL designation indicates the pin has TTL-compatible voltage levels.
11.3 Functional Description
The main components of each GPTM block are two free-running up/down counters (referred to as
Timer A and Timer B), two match registers, two prescaler match registers, two shadow registers,
and two load/initialization registers and their associated control functions. The exact functionality of
each GPTM is controlled by software and configured through the register interface. Timer A and
Timer B can be used individually, in which case they have a 16-bit counting range. In addition, Timer
A and Timer B can be concatenated to provide a 32-bit counting range. Note that the prescaler can
only be used when the timers are used individually.
The available modes for each GPTM block are shown in Table 11-4 on page 528. Note that when
counting down in one-shot or periodic modes, the prescaler acts as a true prescaler and contains
the least-significant bits of the count. When counting up in one-shot or periodic modes, the prescaler
acts as a timer extension and holds the most-significant bits of the count. In input edge count mode,
the prescaler always acts as a timer extension, regardless of the count direction.
Table 11-4. General-Purpose Timer Capabilities
Mode
Timer Use
Count Direction
One-shot
Individual
Concatenated
Up or Down
Up or Down
Periodic
Individual
Concatenated
Up or Down
Up or Down
RTC
Concatenated
Up
Edge Count
Individual
Down
Edge Time
Individual
Down
PWM
Individual
Down
a. The prescaler is only available when the timers are used individually
Counter Size
16-bit
32-bit
16-bit
32-bit
32-bit
16-bit
16-bit
16-bit
Prescaler Size^a
8-bit
-
8-bit
-
-
8-bit
-
-
Software configures the GPTM using the GPTM Configuration (GPTMCFG) register (see page 541),
the GPTM Timer A Mode (GPTMTAMR) register (see page 542), and the GPTM Timer B Mode
528
July 03, 2014
Texas Instruments-Production Data