XC68HC705JJ7 Motorola, XC68HC705JJ7 Datasheet - Page 165

• Manufacturer Part Number: XC68HC705JJ7
• Description: MICROCONTROLLER
• Manufacturer: Motorola

11.5 Input Capture Registers
MC68HC705JJ7 • MC68HC705JP7 — REV 4
MOTOROLA
NOTE:
Address:
Address:
The input capture function is a means to record the time at which an
event occurs. The source of the event can be the change on an external
pin (PB3/AN3/TCAP) or the CPF2 flag bit of voltage comparator 2 in the
analog subsystem. The ICEN bit in the analog subsystem control
register (ACR) at $001D selects which source is the input signal. When
the input capture circuitry detects an active edge on the selected source,
it latches the contents of the free-running timer counter registers into the
input capture registers as shown in
Both the ICEN bit in the ACR and the IEDG bit in the TCR must be set
when using voltage comparator 2 to trigger the input capture function.
Latching values into the input capture registers at successive edges of
the same polarity measures the period of the selected input signal.
Latching the counter values at successive edges of opposite polarity
measures the pulse width of the signal.
Reset:
Reset:
Read:
Read:
Write:
Write:
Figure 11-5. Alternate Counter Registers (ACRH and ACRL)
$001A
$001B
Bit 15
Bit 7
Bit 7
Bit 7
1
1
Programmable Timer
= Unimplemented
14
6
1
6
6
1
13
5
1
5
5
1
12
4
1
4
4
1
Figure
11
3
1
3
3
1
11-6.
10
2
1
2
2
1
Input Capture Registers
Programmable Timer
Advance Information
1
9
1
1
1
0
Bit 0
Bit 8
Bit 0
Bit 0
1
0
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