MC68HC908AB32 Datasheet, PDF (335/392 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Input/Output (I/O) Ports
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.
Address: $000B
Bit 7
6
5
4
3
2
Read: 0
0
0
0
0
0
Write:
Reset:
Unaffected by reset
Alternative Function:
Figure 17-25. Port H Data Register (PTH)
1
PTH1
Bit 0
PTH0
KBD4 KBD3
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.
MC68HC908AB32 — Rev. 1.1
Freescale Semiconductor
Input/Output (I/O) Ports
Technical Data
335