MC68HC708XL36 FREESCALE [Freescale Semiconductor, Inc], MC68HC708XL36 Datasheet - Page 177

• Manufacturer Part Number: MC68HC708XL36
• Description: HCMOS Microcontroller Unit
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

TIM Counter
Prescaler
Input Capture
Output Compare
Unbuffered
Output Compare
7-tim4_b
MOTOROLA
The TIM clock source can be one of the seven prescaler outputs or the
TIM clock pin, TCLK. 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.
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 capture latency can be up to three bus clock
cycles. Input captures can generate TIM CPU interrupt requests or
TIM DMA service requests.
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 or TIM DMA service requests.
Any output compare channel can generate unbuffered output compare
pulses as described in
because changing the output compare value requires writing the new
value over the old value currently in the TIM channel registers.
An unsynchronized write to the TIM channel registers to change an
output compare value could cause incorrect operation for up to two
counter overflow periods. For example, writing a new value before the
counter reaches the old value but after the counter reaches the new
value prevents any compare during that counter overflow period. Also,
using a TIM overflow interrupt routine to write a new, smaller output
compare value may cause the compare to be missed. The TIM may pass
the new value before it is written.
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TIM
Output
Compare. The pulses are unbuffered
Functional Description
MC68HC708XL36
TIM
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