DSP56303 FREESCALE [Freescale Semiconductor, Inc], DSP56303 Datasheet - Page 217

• Manufacturer Part Number: DSP56303
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Freescale Semiconductor
Bit Number
13
12
11
10
9
8
Table 9-3. Timer Control/Status Register (TCSR) Bit Definitions (Continued)
Bit Name
TRM
DIR
INV
DO
DI
Reset Value
0
0
0
0
0
0
DSP56303 User’s Manual, Rev. 2
Data Output
The source of the TIO value when it is a data output signal. The TIO signal is
a data output when the GPIO mode is enabled and DIR is set. A value written
to the DO bit is written to the TIO signal. If the INV bit is set, the value of the
DO bit is inverted when written to the TIO signal. When the INV bit is cleared,
the value of the DO bit is written directly to the TIO signal. When GPIO mode
is disabled, writing to the DO bit has no effect.
Data Input
Reflects the value of the TIO signal. If the INV bit is set, the value of the TIO
signal is inverted before it is written to the DI bit. If the INV bit is cleared, the
value of the TIO signal is written directly to the DI bit.
Direction
Determines the behavior of the TIO signal when it functions as a GPIO signal.
When DIR is set, the TIO signal is an output; when DIR is cleared, the TIO
signal is an input. The TIO signal functions as a GPIO signal only when the
TC[3–0] bits are cleared. If any of the TC[3–0] bits are set, then the GPIO
function is disabled, and the DIR bit has no effect.
Reserved. Write to zero for future compatibility.
Timer Reload Mode
Controls the counter preload operation. In timer (0–3) and watchdog (9–10)
modes, the counter is preloaded with the TLR value after the TCSR[TE] bit is
set and the first internal or external clock signal is received. If the TRM bit is
set, the counter is reloaded each time after it reaches the value contained by
the TCR. In PWM mode (7), the counter is reloaded each time counter
overflow occurs. In measurement (4–5) modes, if the TRM and the TCSR[TE]
bits are set, the counter is preloaded with the TLR value on each appropriate
edge of the input signal. If the TRM bit is cleared, the counter operates as a
free running counter and is incremented on each incoming event.
Inverter
Affects the polarity definition of the incoming signal on the TIO signal when
TIO is programmed as input. It also affects the polarity of the output pulse
generated on the TIO signal when TIO is programmed as output. See Table
9-4, Inverter (INV) Bit Operation, on page 9-27. The INV bit does not affect
the polarity of the prescaler source when the TIO is input to the prescaler.
Note:
The INV bit affects both the timer and GPIO modes of operation. To
ensure correct operation, change this bit only when one or both of
the following conditions is true: the timer is disabled (the TCSR[TE]
bit is cleared). The timer is in GPIO mode.
Description
Triple Timer Module Programming Model
9-25