Intel 8XC196NP, 80C196NU manual Table C-10. PxDIR Addresses and Reset Values, XDIR Address

8XC196NP, 80C196NU USER’S MANUAL

Px_DIR

Px_DIR	Address:	Table C-10
x = 1–4	Reset State:

Each pin of port x can operate in any of the standard I/O modes of operation: complementary output, open-drain output, or high-impedance input. The port x I/O direction (Px_DIR) register determines the I/O direction for each port x pin. The register settings for an open-drain output or a high-impedance input are identical. An open-drain output configuration requires an external pull-up. A high-impedance input configuration requires that the corresponding bit in Px_REG be set.

	7										0
x = 1–3		PIN7	PIN6		PIN5	PIN4		PIN3	PIN2	PIN1	PIN0
		7									0
x = 4
		—	—		—	—		PIN3	PIN2	PIN1	PIN0
Bit		Bit					Function
Number	Mnemonic
7:0	PIN7:0		Port x Pin y Direction
			This bit selects the Px.y direction:
			0 =	complementary output (output only)
			1 =	input or open-drain output (input, output, or bidirectional Open-
				drain outputs require external pull-ups.

Table C-10. Px_DIR Addresses and Reset Values

Register	Address	Reset Value
P1_DIR	1FD2H	FFH
P2_DIR	1FD3H	FFH
P3_DIR	1FDAH	FFH
P4_DIR	1FDBH	FFH

C-30