
Technical Data
MC68HC11E Family
—
Rev. 4
186
Timing System
MOTOROLA
Timing System
9.4.3 Timer Input Capture 4/Output Compare 5 Register
Use TI4/O5 as either an input capture register or an output compare
register, depending on the function chosen for the PA3 pin. To enable it
as an input capture pin, set the I4/O5 bit in the pulse accumulator control
register (PACTL) to logic level 1. To use it as an output compare register,
set the I4/O5 bit to a logic level 0. Refer to
9.8 Pulse Accumulator
.
9.5 Output Compare
Use the output compare (OC) function to program an action to occur at
a specific time
—
when the 16-bit counter reaches a specified value. For
each of the five output compare functions, there is a separate 16-bit
compare register and a dedicated 16-bit comparator. The value in the
compare register is compared to the value of the free-running counter on
every bus cycle. When the compare register matches the counter value,
an output compare status flag is set. The flag can be used to initiate the
automatic actions for that output compare function.
To produce a pulse of a specific duration, write a value to the output
compare register that represents the time the leading edge of the pulse
is to occur. The output compare circuit is configured to set the
Register name: Timer Input Capture 4/Output Compare 5 (High)
Bit 7
6
Address: $101E
5
4
3
2
1
Bit 0
Read:
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Write:
Reset:
1
1
1
1
1
1
1
1
Register name: Timer Input Capture 4/Output Compare 5 (Low)
Address: $101F
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:
1
1
1
1
1
1
1
1
Figure 9-7. Timer Input Capture 4/Output
Compare 5 Register Pair (TI4/O5)