MC68HC908JB8 Datasheet, PDF (202/286 Pages) Motorola, Inc – MICROCONTROLLERS

Input/Output Ports (I/O)
12.3 Port A
Port A is an 8-bit general-purpose bidirectional I/O port with software
configurable pullups, and it shares its pins with the keyboard interrupt
module (KBI).
12.3.1 Port A Data Register
The port A data register contains a data latch for each of the eight port A
pins.
Address: $0000
Bit 7
6
5
4
3
2
1
Bit 0
Read:
PTA7 PTA6 PTA5 PTA4 PTA3 PTA2 PTA1 PTA0
Write:
Reset:
Unaffected by reset
Alternativ
e
Function:
KBA7
KBA6
KBA5
KBA4
KBA3
KBA2
KBA1
KBA0
Additional Optional Optional Optional Optional Optional Optional Optional Optional
Function: pullup pullup pullup pullup pullup pullup pullup pullup
Figure 12-2. Port A Data Register (PTA)
PTA[7:0] — Port A Data Bits
These read/write bits are software programmable. Data direction of
each port A pin is under the control of the corresponding bit in data
direction register A. Reset has no effect on port A data.
The port A pullup enable bit, PAP, in the port option control register
(POCR) enables pullups on port A pins if the respective pin is
configured as an input. (See 12.8 Port Options.)
KBA7–KBA0 — Keyboard Interrupts
The keyboard interrupt enable bits, KBIE7–KBIE0, in the keyboard
interrupt enable register (KBIER), enable the port A pins as external
interrupt pins. (See Section 14. Keyboard Interrupt Module (KBI).)
Technical Data
202
MC68HC908JB8•MC68HC08JB8•MC68HC08JT8 — Rev. 2.3
Input/Output Ports (I/O)
Freescale Semiconductor