MC68HC11PH8 Datasheet, PDF (138/264 Pages) Motorola, Inc – High-density Complementary Metal Oxide Semiconductor (HCMOS) Microcomputer Unit

T16EN — 16-bit timer clock enable
1 (set) – 16-bit timer clock enabled.
0 (clear) – 16-bit timer clock disabled.
Power consumption may be reduced by disabling the 16-bit timer clock. This bit cannot be cleared
whilst VDDSYN is low, as then the 16-bit timer provides the clock source for the COP and RTI.
When VDDSYN is high, the 8-bit modulus timer A supplies the clock source for the COP and RTI
functions, which are therefore independent from the 16-bit timer clock. Reset sets this bit.
WEN — WAIT enable (See Section 2.5.4.1)
1 (set) – Low-power WAIT mode selected (PLL set to ‘idle’ in WAIT mode).
0 (clear) – Do not alter the 4XCLK during WAIT mode.
8.1.2 Timer structure
The timer functions share I/O with all eight pins of port A:
Pin
Alternate function
8
PA0 IC3
PA1 IC2
PA2 IC1
PA3 OC5 and/or OC1, or IC4
PA4 OC4 and/or OC1
PA5 OC3 and/or OC1
PA6 OC2 and/or OC1
PA7 PAI and/or OC1
Figure 8-3 shows the capture/compare system block diagram. The port A pin control block
includes logic for timer functions and for general-purpose I/O. For pins PA3, PA2, PA1 and PA0,
this block contains both the edge-detection logic and the control logic that enables the selection
of which edge triggers an input capture. The digital level on PA[3:0] can be read at any time (read
PORTA register), even if the pin is being used for the input capture function. Pins PA[6:3] are used
either for general-purpose I/O, or as output compare pins. When one of these pins is being used
for an output compare function, it cannot be written directly as if it were a general-purpose output.
Each of the output compare functions (OC[5:2]) is related to one of the port A output pins. Output
compare 1 (OC1) has extra control logic, allowing it optional control of any combination of the
PA[7:3] pins. The PA7 pin can be used as a general-purpose I/O pin, as an input to the pulse
accumulator or as an OC1 output pin.
MOTOROLA
8-4
TIMING SYSTEM
TPG
MC68HC11PH8