mc68hc908gr8vp Freescale Semiconductor, Inc, mc68hc908gr8vp Datasheet - Page 230

• Manufacturer Part Number: mc68hc908gr8vp
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Timer Interface Module (TIM)
22.4 Functional Description
Figure 22-1
that can operate as a free-running counter or a modulo up-counter. The TIM counter provides the timing
reference for the input capture and output compare functions. The TIM counter modulo registers,
TMODH:TMODL, control the modulo value of the TIM counter. Software can read the TIM counter value
at any time without affecting the counting sequence.
The TIM channels (per timer) are programmable independently as input capture or output compare
channels. If a channel is configured as input capture, then an internal pullup device may be enabled for
that channel. See
In
TIM2.
Figure 22-2
22.4.1 TIM Counter Prescaler
The TIM clock source can be one of the seven prescaler outputs. The prescaler generates seven clock
rates from the internal bus clock. The prescaler select bits, PS[2:0], in the TIM status and control register
select the TIM clock source.
22.4.2 Input Capture
With the input capture function, the TIM can capture the time at which an external event occurs. When an
active edge occurs on the pin of an input capture channel, the TIM latches the contents of the TIM counter
into the TIM channel registers, TCHxH:TCHxL. The polarity of the active edge is programmable. Input
captures can generate TIM CPU interrupt requests.
22.4.3 Output Compare
With the output compare function, the TIM can generate a periodic pulse with a programmable polarity,
duration, and frequency. When the counter reaches the value in the registers of an output compare
channel, the TIM can set, clear, or toggle the channel pin. Output compares can generate TIM CPU
interrupt requests.
230
Figure
22-1, channel1 will only be available in TIM1 while channel 0 will be available in both TIM1 and
shows the structure of the TIM. The central component of the TIM is the 16-bit TIM counter
summarizes the timer registers.
References to either timer 1 or timer 2 may be made in the following text by
omitting the timer number. For example, TCH0 may refer generically to
T1CH0 and T2CH0, and TCH1 will refer to T1CH1.
The Timer Interface Module in MC68HC908GR8 is constructed by TIM1
which contains channel 0 and 1, and TIM2 which contains channel 0 only.
Port D Input Pullup Enable
MC68HC908GR8 • MC68HC908GR4 Data Sheet, Rev. 7
Register.
NOTE
NOTE
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