Intel 8XC196MD, 8XC196MH, 8XC196MC manual Internal Peripherals, State Times at Various Frequencies

8XC196MC, MD, MH USER’S MANUAL

XTAL1

TXTAL1 TXTAL1

1 State Time 1 State Time

PH1

PH2

CLKOUT

Phase 1 Phase 2 Phase 1 Phase 2

A0114-04

Figure 2-4. Internal Clock Phases

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.

Table 2-2. State Times at Various Frequencies

FXTAL1	State Time
(Frequency Input to the
Divide-by-two Circuit)
8 MHz	250 ns
12 MHz	167 ns
16 MHz	125 ns

The following formulas calculate the frequency of PH1 and PH2, the duration of a state time, and the duration of a clock period (TXTAL1).

	FXT AL1			2	1
PH1 (in MHz) =	------------------=	PH2	State Time (in µs) =	------------------TXTAL1	= ------------------
	2			FXTAL1	FXTAL1

Because the microcontroller can operate at many frequencies, this manual defines time require- ments (such as instruction execution times) in terms of state times rather than specific measure- ments. Datasheets list AC characteristics in terms of clock periods (TXTAL1 or TOSC).

2.5INTERNAL PERIPHERALS

The internal peripheral modules provide special functions for a variety of applications. This sec- tion provides a brief description of the peripherals; subsequent chapters describe them in detail.

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