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XTAL1
PH1
PH2
CLKOUT
The combined period of phase 1 and phase 2 of the internal CLKOUT signal defines the basic
time unit known as a state time or state. Table 2-2 lists state time durations at various frequencies.
The following formulas calculate the frequency of PH1 and PH2 and the duration of a state time
(F
is the input frequency to the divide-by-two circuit).
OSC
F
osc
---------- -
PH1 (in MHz)
=
=
2
Because the device can operate at many frequencies, this manual defines time requirements in
terms of state times rather than specific times. Consult the latest datasheet for AC timing specifi-
cations.
(Frequency Input to the
Divide-by-two Circuit)
2.5
INTERNAL PERIPHERALS
The internal peripheral modules provide special functions for a variety of applications. This sec-
tion provides a brief description of each peripheral and other chapters describe each one in detail.
1 State Time
Phase 1
Phase 2
Figure 2-4. Internal Clock Phases
PH2 (in MHz)
Table 2-2. State Times at Various Frequencies
F
OSC
8 MHz
12 MHz
16 MHz
20 MHz
ARCHITECTURAL OVERVIEW
1 State Time
Phase 1
Phase 2
State Time (in seconds)
State Time
250 ns
167 ns
125 ns
100 ns
A0114-02
2
---------- -
=
F
osc
2-7
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