mc68hc05jp6pe Freescale Semiconductor, Inc, mc68hc05jp6pe Datasheet - Page 162

• Manufacturer Part Number: mc68hc05jp6pe
• Description: M68hc05 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Programmable Timer
11.5 Input Capture Registers
General Release Specification
162
TCAP
PB3
AN3
RESET
SUBSYSTEM
ANALOG
NOTE:
CONTROL
FROM
CPF2
FLAG
ICEN
BIT
BIT
SELECT
READ
ICRH
INPUT
MUX
Figure 11-6. Timer Input Capture Block Diagram
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.
& DETECT
SELECT
LOGIC
EDGE
$0012
TIMER CONTROL REG.
Programmable Timer
LATCH
ICRH ($0014)
INPUT CAPTURE (ICF)
16-BIT COUNTER
ICRL ($0015)
MC68HC05JJ6/MC68HC05JP6
Figure
TIMER STATUS REG.
11-6.
$0013
Freescale Semiconductor
4
INTERNAL
INTERNAL
DATA
DATA
BUS
BUS
INTERNAL
(OSC 2)
READ
ICRL
INTERRUPT
CLOCK
REQUEST
TIMER
—
Rev. 3.2