MC68HC11KW1 Datasheet, PDF (158/238 Pages) Motorola, Inc – High-density complementary metal oxide semiconductor HCMOS) microcontroller unit

9.1.2.1 TCTL2 — Timer control register 2
Timer control 2 (TCTL2)
Address bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
State
on reset
$0021 EDG4B EDG4A EDG1B EDG1A EDG2B EDG2A EDG3B EDG3A 0000 0000
Use the control bits of this register to program input capture functions to detect a particular edge
polarity on the corresponding timer input pin. Each of the input capture functions can be
independently configured to detect rising edges only, falling edges only, any edge (rising or falling),
or to disable the input capture function. The input capture functions operate independently of each
other and can capture the same TCNT value if the input edges are detected within the same timer
count cycle.
EDGxB and EDGxA — Input capture edge control
EDGxB EDGxA
Configuration
0
0 ICx disabled
0
1 ICx captures on rising edges only
1
0 ICx captures on falling edges only
1
1 ICx captures on any edge
There are four pairs of these bits. Each pair is cleared by reset and must be encoded to configure
the corresponding input capture edge detector circuit. IC4 functions only if the I4/O5 bit in the
9
PACTL register is set.
TIMING SYSTEM
MC68HC11KW1
9-6