Datasheet

Timer Interface Module (TIM)

Functional Description

MC68HC908GR8 — Rev 4.0 Technical Data

MOTOROLA Timer Interface Module (TIM) 337

NOTE: 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.

NOTE: The Timer Interface Module in MC68HC908GR8 is constructed by TIM1

which is contained channel 0 and 1, and TIM2 which is contained

channel 0 only.

22.5 Functional Description

NOTE: References to TCLK and external TIM clock input are only valid if the

MCU has an external TCLK pin. If the MCU has no external TCLK pin,

the TIM module must use the internal bus clock prescaler selections.

Figure 22-1 shows the structure of the TIM. The central component of

the TIM is the 16-bit TIM counter 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 Port D Input Pullup Enable Register.

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cale Semiconductor,

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