Datasheet

Chapter 13 Timer Module (TIM16B4CV1)
MC9S12E128 Data Sheet, Rev. 1.07
434 Freescale Semiconductor
13.3.2.17 Pulse Accumulators Count Registers (PACNT)
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
Reading the pulse accumulator counter registers immediately after an active
edge on the pulse accumulator input pin may miss the last count because the
input has to be synchronized with the bus clock first.
15 14 13 12 11 10 9 0
R
PACNT15 PACNT14 PACNT13 PACNT12 PACNT11 PACNT10 PACNT9 PACNT8
W
Reset 0 0 0 00000
Figure 13-24. Pulse Accumulator Count Register High (PACNTH)
76543210
R
PACNT7 PACNT6 PACNT5 PACNT4 PACNT3 PACNT2 PACNT1 PACNT0
W
Reset 0 0 0 00000
Figure 13-25. Pulse Accumulator Count Register Low (PACNTL)