D.2.7 PACTL
— Pulse Accumulator Control Register
PACNT
— Pulse Accumulator Counter
15
PAIS
RESET:
U
0
0
0
U
0
0
0
0
0
0
0
0
0
14
PAEN
13
PAMOD
12
PEDGE
11
PCLKS
10
I4/O5
9
PACLK
8
7
PACNT
$YFF90C
$YFF90D
0
0
0
PACTL enables the pulse accumulator and selects either event counting or gated
mode. In event counting mode, PACNT is incremented each time an event occurs. In
gated mode, it is incremented by an internal clock.
PAIS — PAI Pin State (Read Only)
PAEN — Pulse Accumulator Enable
0 = Pulse accumulator disabled
1 = Pulse accumulator enabled
PAMOD — Pulse Accumulator Mode
0 = External event counting
1 = Gated time accumulation
PEDGE — Pulse Accumulator Edge Control
The effects of PEDGE and PAMOD are shown in the following table.
PAMOD
0
0
1
1
PEDGE
0
1
0
1
Effect
PAI Falling Edge Increments Counter
PAI Rising Edge Increments Counter
Zero on PAI Inhibits Counting
One on PAI Inhibits Counting
D
PCLKS — PCLK Pin State (Read Only)
I4/O5 — Input Capture 4/Output Compare 5
0 = Output compare 5 enabled
1 = Input capture 4 enabled
PACLK[1:0] — Pulse Accumulator Clock Select (Gated Mode)
PACLK[1:0]
00
01
10
11
Pulse Accumulator Clock Selected
System Clock Divided by 512
Same Clock Used to Increment TCNT
TOF Flag from TCNT
External Clock, PCLK
PACNT — Pulse Accumulator Counter
Eight-bit read/write counter used for external event counting or gated time accumula-
tion.
MC68331
USER’S MANUAL
REGISTER SUMMARY
MOTOROLA
D-7
MOTOROLA [ MOTOROLA, INC ]
