Intel 8XC196MH, 8XC196MD Reducing Power Consumption, P1MODEMH, P7MODEMD 1FD1H, P1REG MH 1F9DH

		SPECIAL OPERATING MODES
Table 14-2. Operating Mode Control and Status Registers (Continued)
Mnemonic	Address	Description
P1_DIR (MH)	1F9BH	Port x Direction
P2_DIR	1FD2H	Each bit of Px_DIR controls the direction of the corresponding pin.
P5_DIR	1FF3H
		Clearing a bit configures a pin as a complementary output; setting
P7_DIR (MD)	1FD3H
		a bit configures a pin as an input or open-drain output. (Open-
		drain outputs require external pull-ups.)
P1_MODE(MH)	1F99H	Port x Mode
P2_MODE	1FD0H	Each bit of Px_MODE controls whether the corresponding pin
P5_MODE	1FF1H
		functions as a standard I/O port pin or as a special-function
P7_MODE(MD)	1FD1H
		signal. Setting a bit configures a pin as a special-function signal;
		clearing a bit configures a pin as a standard I/O port pin.
P1_REG (MH)	1F9DH	Port x Data Output
P2_REG	1FD4H	For an input, set the corresponding Px_REG bit.
P5_REG	1FF5H
		For an output, write the data to be driven out by each pin to the
P7_REG (MD)	1FD5H
		corresponding bit of Px_REG. When a pin is configured as
		standard I/O (Px_MODE.y = 0), the result of a CPU write to
		Px_REG is immediately visible on the pin. When a pin is
		configured as a special-function signal (Px_MODE.y = 1), the
		associated on-chip peripheral or off-chip component controls the
		pin. The CPU can still write to Px_REG, but the pin is unaffected
		until it is switched back to its standard I/O function.
		This feature allows software to configure a pin as standard I/O
		(clear Px_MODE.y), initialize or overwrite the pin value, then
		configure the pin as a special-function signal (set Px_MODE.y). In
		this way, initialization, fault recovery, exception handling, etc., can
		be done without changing the operation of the associated
		peripheral.

14.2 REDUCING POWER CONSUMPTION

Both power-saving modes conserve power by disabling portions of the internal clock circuitry (Figure 14-1). The following paragraphs describe both modes in detail.

14-3