mc68hc05pv8a Freescale Semiconductor, Inc, mc68hc05pv8a Datasheet - Page 117

• Manufacturer Part Number: mc68hc05pv8a
• Description: Mc68hc05pv8a Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

8.1 Contents
8.2 Introduction
MC68HC(8)05PV8/A — Rev. 1.9
Technical Data — MC68HC(8)05PV8/A
8.2
8.3
8.3.1
8.3.2
8.3.3
8.4
8.5
The core timer for this device is a 15-stage multi-functional ripple
counter. The features include timer over flow, power-on reset (POR),
real time interrupt (RTI), and COP watchdog timer.
As seen in
circuit followed by a fixed divide by four pre-scaler. This signal drives an
8-bit ripple counter. The value of this 8-bit ripple counter can be read by
the CPU at any time by accessing the timer counter register (TCR) at
address $09. A timer overflow function is implemented on the last stage
of this counter, giving a possible interrupt at the rate of f
additional stages produce the POR function after 4064 clks (if selected).
The timer counter bypass circuitry (available only in test mode) is at this
point in the timer chain. This circuit is followed by two more stages, with
the resulting clock (f
RTI circuit consists of three divider stages with a 1 of 4 selector. The
output of the RTI circuit is further divided by eight to drive the mask
optional COP watchdog timer circuit. The RTI rate selector bits, and the
Freescale Semiconductor, Inc.
For More Information On This Product,
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Core Timer During WAIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
Core Timer During STOP . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
Core Timer Status & Control Register (CTSCR) . . . . . . . .119
Computer Operating Properly (COP) Watchdog Reset. . . 121
Core Timer Counter Register (CTCR). . . . . . . . . . . . . . . . 121
Figure
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8-1, the timer is driven by the output of the clock select
Core Timer
op
/16384) driving the real time interrupt circuit. The
Section 8. Core Timer
op
/1024. Two
Technical Data