Timer Operational Modes - Motorola DSP56309 User Manual

Triple Timer Module

Timer Operational Modes

9.3.6 Timer Compare Register (TCPR)
The TCPR is a 24-bit, read/write register that contains the value to be compared to the
counter value. These two values are compared every timer clock after the TE bit in the
TCSR is set. When the values match, the timer compare flag (TCF) bit is set and an
interrupt is generated if interrupts are enabled (if the timer compare interrupt enable
(TCIE) bit in the TCSR is set). The TCPR is ignored in measurement modes.
9.3.7 Timer Count Register (TCR)
The Timer Count Register (TCR) is a 24-bit, read-only register. In timer and watchdog
modes, the counterÕs contents can be read at any time by reading the TCR register. In
Measurement modes, the TCR is loaded with the current value of the counter on the
appropriate edge of the input signal, and its value can be read to determine the width,
period, or delay of the leading edge of the input signal. When the timer is in
measurement modes, the TIO signal is used for the input signal.
9.4 TIMER OPERATIONAL MODES
Each timer has these operational modes to meet a variety of system requirements:
¥ Timer
Ð GPIO, mode 0: Internal timer interrupt generated by the internal clock
Ð Pulse, mode 1: External timer pulse generated by the internal clock
Ð Toggle, mode 2: Output timing signal toggled by the internal clock
Ð Event counter, mode 3: Internal timer interrupt generated by an external clock
¥ Measurement
Ð Input width, mode 4: Input pulse width measurement
Ð Input pulse, mode 5: Input signal period measurement
Ð Capture, mode 6: Capture external signal
¥ PWM, mode 7: Pulse width modulation
¥ Watchdog
Ð Pulse, mode 9: Output pulse, internal clock
9-16 DSP56309UM/D MOTOROLA