MC9S12GRMV1 Datasheet, PDF (747/1292 Pages) Freescale Semiconductor, Inc – MC9S12G Family Reference Manual and Data Sheet

Timer Module (TIM16B6CV3)
By enabling the PRNT bit of the TSCR1 register, the performance of the timer can be enhanced. In this
case, it is possible to set additional prescaler settings for the main timer counter in the present timer by
using PTPSR[7:0] bits of PTPSR register generating divide by 1, 2, 3, 4,....20, 21, 22, 23,......255, or 256.
22.4.2 Input Capture
Clearing the I/O (input/output) select bit, IOSx, configures channel x as an input capture channel. The
input capture function captures the time at which an external event occurs. When an active edge occurs on
the pin of an input capture channel, the timer transfers the value in the timer counter into the timer channel
registers, TCx.
The minimum pulse width for the input capture input is greater than two bus clocks.
An input capture on channel x sets the CxF flag. The CxI bit enables the CxF flag to generate interrupt
requests. Timer module must stay enabled (TEN bit of TSCR1 register must be set to one) while clearing
CxF (writing one to CxF).
22.4.3 Output Compare
Setting the I/O select bit, IOSx, configures channel x when available as an output compare channel. The
output compare function can generate a periodic pulse with a programmable polarity, duration, and
frequency. When the timer counter reaches the value in the channel registers of an output compare channel,
the timer can set, clear, or toggle the channel pin if the corresponding OCPDx bit is set to zero. An output
compare on channel x sets the CxF flag. The CxI bit enables the CxF flag to generate interrupt requests.
Timer module must stay enabled (TEN bit of TSCR1 register must be set to one) while clearing CxF
(writing one to CxF).
The output mode and level bits, OMx and OLx, select set, clear, toggle on output compare. Clearing both
OMx and OLx results in no output compare action on the output compare channel pin.
Setting a force output compare bit, FOCx, causes an output compare on channel x. A forced output
compare does not set the channel flag.
Writing to the timer port bit of an output compare pin does not affect the pin state. The value written is
stored in an internal latch. When the pin becomes available for general-purpose output, the last value
written to the bit appears at the pin.
22.4.3.1 OC Channel Initialization
The internal register whose output drives OCx can be programmed before the timer drives OCx. The
desired state can be programmed to this internal register by writing a one to CFORCx bit with TIOSx,
OCPDx and TEN bits set to one.
Set OCx: Write a 1 to FOCx while TEN=1, IOSx=1, OMx=1, OLx=1 and OCPDx=1
Clear OCx: Write a 1 to FOCx while TEN=1, IOSx=1, OMx=1, OLx=0 and OCPDx=1
MC9S12G Family Reference Manual, Rev.1.23
Freescale Semiconductor
749