Chapter 22 Timer Module (TIM16B8CV2) Block Description
MC9S12XE-Family Reference Manual Rev. 1.19
Freescale Semiconductor
801
22.3.2.11 Timer System Control Register 2 (TSCR2)
Read: Anytime
Write: Anytime.
NOTE
The newly selected prescale factor will not take effect until the next
synchronized edge where all prescale counter stages equal zero.
Module Base + 0x000D
7
6
5
4
3
2
1
0
R
TOI
0
0
0
TCRE
PR2
PR1
PR0
W
Reset
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 22-19. Timer System Control Register 2 (TSCR2)
Table 22-13. TSCR2 Field Descriptions
Field
Description
7
TOI
Timer Overflow Interrupt Enable
0 Interrupt inhibited.
1 Hardware interrupt requested when TOF flag set.
3
TCRE
Timer Counter Reset Enable
— This bit allows the timer counter to be reset by a successful output compare 7
event. This mode of operation is similar to an up-counting modulus counter.
0 Counter reset inhibited and counter free runs.
1 Counter reset by a successful output compare 7.
If TC7 = 0x0000 and TCRE = 1, TCNT will stay at 0x0000 continuously. If TC7 = 0xFFFF and TCRE = 1, TOF
will never be set when TCNT is reset from 0xFFFF to 0x0000.
2
PR[2:0]
Timer Prescaler Select
— These three bits select the frequency of the timer prescaler clock derived from the
Bus Clock as shown in
.
Table 22-14. Timer Clock Selection
PR2
PR1
PR0
Timer Clock
0
0
0
Bus Clock / 1
0
0
1
Bus Clock / 2
0
1
0
Bus Clock / 4
0
1
1
Bus Clock / 8
1
0
0
Bus Clock / 16
1
0
1
Bus Clock / 32
1
1
0
Bus Clock / 64
1
1
1
Bus Clock / 128
Because
of
an
order
from
the
United
States
International
Trade
Commission,
BGA-packaged
product
lines
and
part
numbers
indicated
here
currently
are
not
available
from
Freescale
for
import
or
sale
in
the
United
States
prior
to
September
2010:
S12XE
products
in
208
MAPBGA
packages
