MC68HC908QC16_07 Datasheet, PDF (212/274 Pages) Freescale Semiconductor, Inc – Microcontrollers

Timer Interface Module (TIM2)
To allow software to clear status bits during a break interrupt, write a 1 to BCFE. If a status bit is cleared
during the break state, it remains cleared when the MCU exits the break state.
To protect status bits during the break state, write a 0 to BCFE. With BCFE cleared (its default state),
software can read and write registers during the break state without affecting status bits. Some status bits
have a two-step read/write clearing procedure. If software does the first step on such a bit before the
break, the bit cannot change during the break state as long as BCFE is cleared. After the break, doing the
second step clears the status bit.
17.7 I/O Signals
The TIM2 module can share its pins with the general-purpose I/O pins. See Figure 17-1 for the port pins
that are shared.
17.7.1 TIM2 Channel I/O Pins (T2CH1:T2CH0)
Each channel I/O pin is programmable independently as an input capture pin or an output compare pin.
T2CH0 can be configured as buffered output compare or buffered PWM pin.
17.7.2 TIM2 Clock Pin (T2CLK)
T2CLK is an external clock input that can be the clock source for the counter instead of the prescaled
internal bus clock. Select the T2CLK input by writing 1s to the three prescaler select bits, PS[2:0]. The
minimum T2CLK pulse width is specified in the Timer Interface Module Characteristics table in the
Electricals section. The maximum T2CLK frequency is the least of 4 MHz or bus
frequency ÷ 2.
17.8 Registers
The following registers control and monitor operation of the TIM2:
• TIM2 status and control register (T2SC)
• TIM2 control registers (T2CNTH:T2CNTL)
• TIM2 counter modulo registers (T2MODH:T2MODL)
• TIM2 channel status and control registers (T2SC0 and T2SC1)
• TIM2 channel registers (T2CH0H:T2CH0L and T2CH1H:T2CH1L)
17.8.1 TIM2 Status and Control Register
The TIM2 status and control register (T2SC) does the following:
• Enables TIM2 overflow interrupts
• Flags TIM2 overflows
• Stops the counter
• Resets the counter
• Prescales the counter clock
MC68HC908QC16 • MC68HC908QC8 • MC68HC908QC4 Data Sheet, Rev. 3
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Freescale Semiconductor