Freescale Semiconductor MC68HC08KH12 manual Port B, Port a Pin Functions, 188

Table 12-2. Port A Pin Functions

			Accesses	Accesses to PTA
DDRA	PTA Bit	I/O Pin	to DDRA
Bit		Mode
			Read/Write	Read	Write
0	X(1)	Input, Hi-Z(2)	DDRA[7:0]	Pin	PTA[7:0](3)
1	X	Output	DDRA[7:0]	PTA[7:0]	PTA[7:0]

1.X = don’t care

2.Hi-Z = high impedance

3.Writing affects data register, but does not affect input.

12.4 Port B

Port B is an 8-bit general-purpose bidirectional I/O port with software configurable pullups.

12.4.1 Port B Data Register (PTB)

The port B data register contains a data latch for each of the eight port B pins.

Address:

Read:

Write:

Reset:

$0001
Bit 7	6	5	4	3	2	1	Bit 0
PTB7	PTB6	PTB5	PTB4	PTB3	PTB2	PTB1	PTB0

Unaffected by reset

Figure 12-4. Port B Data Register (PTB)

PTB[7:0] — Port B Data Bits

These read/write bits are software-programmable. Data direction of each port B pin is under the control of the corresponding bit in data direction register B. Reset has no effect on port B data.

	The port B pullup enable bit, PBP, in the port option control register
	(POC) enables pullups on port B pins if the respective pin is configured
	as an input. (See 12.9 Port Options.).
Advance Information	MC68HC(7)08KH12 — Rev. 1.1
188	Freescale Semiconductor