mc68hc11d0 Freescale Semiconductor, Inc, mc68hc11d0 Datasheet - Page 103

• Manufacturer Part Number: mc68hc11d0
• Description: Mc68hc11d0 Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

9.6.1 Pulse Accumulator Control Register
DDRA7 — Data Direction Control for Port A Bit 7
PAEN — Pulse Accumulator System Enable
PAMOD — Pulse Accumulator Mode
PEDGE — Pulse Accumulator Edge Control
DDRA3 — Data Direction Register for Port A Bit 3
I4/O5 — Input Capture 4/Output Compare 5
RTR[1:0] — RTI Interrupt Rate Selects
9.6.2 Pulse Accumulator Count Register
TECHNICAL DATA
PACTL — Pulse Accumulator Control
RESET:
Four of this register's bits control an 8-bit pulse accumulator system. Another bit en-
ables either the OC5 function or the IC4 function, while two other bits select the rate
for the real-time interrupt system.
The pulse accumulator uses port A bit 7 as the PAI input, but the pin can also be used
as general-purpose I/O or as an output compare. Note that even when port A bit 7 is
configured as an output, the pin still drives the input to the pulse accumulator. Refer to
SECTION 6 PARALLEL I/O for more information.
This bit has different meanings depending on the state of the PAMOD bit, as shown in
the following table:
Refer to SECTION 6 PARALLEL I/O.
Refer to 9.2 Input Capture.
Refer to 9.4 Real-Time Interrupt.
This 8-bit read/write register contains the count of external input events at the PAI in-
put, or the accumulated count. The counter is not affected by reset and can be read or
written at any time. Counting is synchronized to the internal PH2 clock so that incre-
menting and reading occur during opposite half cycles.
0 = Pulse accumulator disabled
1 = Pulse accumulator enabled
0 = Event counter
1 = Gated time accumulation
DDRA7
Bit 7
0
PAMOD
0
0
1
1
PAEN
Freescale Semiconductor, Inc.
6
0
For More Information On This Product,
PAMOD
PEDGE
Go to: www.freescale.com
5
0
0
1
0
1
TIMING SYSTEM
PEDGE
4
0
PAI Falling Edge Increments the Counter.
PAI Rising Edge Increments the Counter.
A Zero on PAI Inhibits Counting.
A One on PAI Inhibits Counting.
DDRA3
3
0
Action on Clock
I4/O5
2
0
RTR1
1
0
$0026
RTR0
Bit 0
0
9-17