Motorola MC68HC908AB32 User Manual

Input/Output (I/O) Ports
Port H
MC68HC908AB32 — Rev. 1.0 Technical Data
MOTOROLA Input/Output (I/O) Ports 335
17.10 Port H
Port H is a 2-bit special-function port that shares all two of its pins with
the keyboard interrupt (KBI) module.
17.10.1 Port H Data Register (PTH)
The port H data register (PTH) contains a data latch for each of the two
port H pins.
PTH[1:0] — Port H Data Bits
These read/write bits are software programmable. Data direction of
each port H pin is under the control of the corresponding bit in data
direction register H. Reset has no effect on port H data.
KBD[4:3] — The keyboard interrupt enable bits, KBIE[4:3], in the
keyboard interrupt enable register (KBIER), enable the port H pins as
external interrupt pins. See Section 19. Keyboard Interrupt Module
(KBI).
17.10.2 Data Direction Register H (DDRH)
Data direction register H determines whether each port H pin is an input
or an output. Writing logic 1 to a DDRH bit enables the output buffer for
the corresponding port H pin; a logic 0 disables the output buffer.
Address: $000B
Bit 7 654321Bit 0
Read: 000000
PTH1 PTH0
Write:
Reset: Unaffected by reset
Alternative Function: KBD4 KBD3
Figure 17-25. Port H Data Register (PTH)

Motorola MC68HC908AB32 Specifications

General

Brand	Motorola
Model	MC68HC908AB32
Category	Controller
Language	English