mc68hc705e5 Freescale Semiconductor, Inc, mc68hc705e5 Datasheet - Page 55

• Manufacturer Part Number: mc68hc705e5
• Description: M68hc05 Family Of Microcontrollers Mcus
• Manufacturer: Freescale Semiconductor, Inc

8.1 Contents
8.2 Introduction
MC68HC705E5
General Release Specification — MC68HC705E5
—
Rev. 1.0
8.2
8.3
8.4
The timer for this device is a 15-stage multifunctional ripple counter. The
features include timer overflow, power-on reset (POR), and real-time
interrupt.
As seen in
circuit (as determined by the value of BCS in the PLLCR) and then a
fixed divide-by-four prescaler. 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
produce the POR function at f
This circuit is followed by two more stages, with the resulting clock
(f
of three divider stages with a one-of-four selector. The RTI rate selector
bit and the RTI and TOF enable bits and flags are located in the timer
control and status register at location $0008.
op
Freescale Semiconductor, Inc.
/16,384) driving the real-time interrupt circuit. The RTI circuit consists
For More Information On This Product,
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55
Timer Control and Status Register . . . . . . . . . . . . . . . . . . . . . .57
Timer Counter Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59
Figure
Go to: www.freescale.com
8-1, the timer is driven by the output of the clock select
Timer
op
/4064.
op
/1024. Two additional stages
Section 8. Timer
General Release Specification