MC9S12GRMV1 Datasheet, PDF (768/1292 Pages) Freescale Semiconductor, Inc – MC9S12G Family Reference Manual and Data Sheet

Timer Module (TIM16B8CV3)
Field
1
PAOVF
0
PAIF
Table 23-21. PAFLG Field Descriptions
Description
Pulse Accumulator Overflow Flag — Set when the 16-bit pulse accumulator overflows from 0xFFFF to 0x0000.
Clearing this bit requires writing a one to this bit in the PAFLG register while TEN bit of TSCR1 or PAEN bit of
PACTL register is set to one.
Pulse Accumulator Input edge Flag — Set when the selected edge is detected at the IOC7 input pin.In event
mode the event edge triggers PAIF and in gated time accumulation mode the trailing edge of the gate signal at
the IOC7 input pin triggers PAIF.
Clearing this bit requires writing a one to this bit in the PAFLG register while TEN bit of TSCR1 or PAEN bit of
PACTL register is set to one. Any access to the PACNT register will clear all the flags in this register when TFFCA
bit in register TSCR(0x0006) is set.
23.3.2.17 Pulse Accumulators Count Registers (PACNT)
Module Base + 0x0022
15
R
PACNT15
W
14
PACNT14
13
PACNT13
12
PACNT12
11
PACNT11
10
PACNT10
9
PACNT9
Reset
0
0
0
0
0
0
0
Figure 23-26. Pulse Accumulator Count Register High (PACNTH)
1_.
0
PACNT8
0
Module Base + 0x0023
R
W
Reset
7
PACNT7
0
6
PACNT6
5
PACNT5
4
PACNT4
3
PACNT3
2
PACNT2
1
PACNT1
0
0
0
0
0
0
Figure 23-27. Pulse Accumulator Count Register Low (PACNTL)
0
PACNT0
0
Read: Anytime
Write: Anytime
These registers contain the number of active input edges on its input pin since the last reset.
When PACNT overflows from 0xFFFF to 0x0000, the Interrupt flag PAOVF in PAFLG (0x0021) is set.
Full count register access should take place in one clock cycle. A separate read/write for high byte and low
byte will give a different result than accessing them as a word.
NOTE
Readingthepulseaccumulatorcounterregistersimmediatelyafteranactiveedgeonthe
pulseaccumulatorinputpinmaymissthelastcountbecausetheinputhastobesynchronized
with the bus clock first.
MC9S12G Family Reference Manual, Rev.1.23
770
Freescale Semiconductor