mc68hc908jw32 Freescale Semiconductor, Inc, mc68hc908jw32 Datasheet - Page 168

• Manufacturer Part Number: mc68hc908jw32
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Input/Output (I/O) Ports
13.2 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).
13.2.1 Port A Data Register
The port A data register contains a data latch for each of the eight port A pins.
PTA[7:0] — Port A Data Bits
KBA7–KBA0 — Keyboard Interrupts
13.2.2 Data Direction Register A
Data direction register A determines whether each port A pin is an input or an output. Writing a logic 1 to
a DDRA bit enables the output buffer for the corresponding port A pin; a logic 0 disables the output buffer.
168
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 keyboard interrupt enable bits, KBA7–KBA0, in the keyboard interrupt enable register (KBIER),
enable the port A pins as external interrupt pins and the internal pullup of the corresponding pin. (See
Chapter 15 Keyboard Interrupt Module
* DDRA7 bit is reset by POR or LVI reset only.
Alternative
Function:
Additional
Function:
Address:
Address:
Reset:
Reset:
Read:
Read:
Write:
Write:
Optional
DDRA7
$0000
$0004
KBA7
pullup
PTA7
Bit 7
Bit 7
0*
Figure 13-3. Data Direction Register A (DDRA)
Figure 13-2. Port A Data Register (PTA)
Optional
DDRA6
pullup
PTA6
KBA6
6
6
0
MC68HC908JW32 Data Sheet, Rev. 5
Optional
DDRA5
pullup
PTA5
KBA5
(KBI).)
5
5
0
Optional
DDRA4
Unaffected by reset
pullup
PTA4
KBA4
4
4
0
Optional
DDRA3
pullup
PTA3
KBA3
3
3
0
Optional
DDRA2
pullup
PTA2
KBA2
2
2
0
Optional
DDRA1
pullup
PTA1
KBA1
1
1
0
Freescale Semiconductor
Optional
DDRA0
KBA0
pullup
PTA0
Bit 0
Bit 0
0