
Timing System
Data Sheet
M68HC11E Family — Rev. 5
162
Timing System
MOTOROLA
DDRA3 — Data Direction for Port A Bit 3
Refer to
Section 6. Parallel Input/Output (I/O) Ports
.
I4/O5 — Input Capture 4/Output Compare 5 Bit
0 = Output compare 5 function enable (no IC4)
1 = Input capture 4 function enable (no OC5)
RTR[1:0] — RTI Interrupt Rate Select Bits
Refer to
9.5 Real-Time Interrupt (RTI)
.
9.7.2 Pulse Accumulator Count Register
This 8-bit read/write register contains the count of external input events at the PAI
input or the accumulated count. The PACNT is readable even if PAI is not active in
gated time accumulation mode. 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 incrementing and reading occur during opposite half cycles.
9.7.3 Pulse Accumulator Status and Interrupt Bits
The pulse accumulator control bits, PAOVI and PAII, PAOVF and PAIF, are located
within timer registers TMSK2 and TFLG2.
Address:
$1027
Bit 7
6
5
4
3
2
1
Bit 0
Read:
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Write:
Reset:
Indeterminate after reset
Figure 9-26. Pulse Accumulator Count Register (PACNT)
Address:
$1024
Bit 7
6
5
4
3
2
1
Bit 0
Read:
TOI
RTII
PAOVI
PAII
PR1
PR0
Write:
Reset:
0
0
0
0
0
0
0
0
= Unimplemented
Figure 9-27. Timer Interrupt Mask 2 Register (TMSK2)
Address:
$1025
Bit 7
6
5
4
3
2
1
Bit 0
Read:
TOF
RTIF
PAOVF
PAIF
Write:
Reset:
0
0
0
0
0
0
0
0
= Unimplemented
Figure 9-28. Timer Interrupt Flag 2 Register (TFLG2)
F
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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