mc9s08gt16a Freescale Semiconductor, Inc, mc9s08gt16a Datasheet - Page 82

• Manufacturer Part Number: mc9s08gt16a
• Description: Hcs08 Microcontrollers 8-bit Microcontroller Family
• Manufacturer: Freescale Semiconductor, Inc

Parallel Input/Output
6.2
The MC9S08GT16A/GT8A has a total of 39 parallel I/O pins (one is output only) in six 8-bit ports
(PTA–PTE, PTG). Not all pins are bonded out in all packages. Consult the pin assignment in
“Pins and
I/O when they are not used by other on-chip peripheral systems.
After reset, BKGD/MS is enabled and therefore is not usable as an output pin until BKGDPE in SOPT is
cleared. The rest of the peripheral functions are disabled. After reset, all data direction and pullup enable
controls are set to 0s. These pins default to being high-impedance inputs with on-chip pullup devices
disabled.
The following paragraphs discuss each port and the software controls that determine each pin’s use.
6.2.1
Port A is an 8-bit port shared among the KBI keyboard interrupt inputs and general-purpose I/O. Any pins
enabled as KBI inputs will be forced to act as inputs.
Port A pins are available as general-purpose I/O pins controlled by the port A data (PTAD), data direction
(PTADD), pullup enable (PTAPE), and slew rate control (PTASE) registers. Refer to
I/O
Port A can be configured to be keyboard interrupt input pins. Refer to
(S08KBIV1),”
6.2.2
Port B is an 8-bit port shared among the ATD inputs and general-purpose I/O. Any pin enabled as an ATD
input will be forced to act as an input.
Port B pins are available as general-purpose I/O pins controlled by the port B data (PTBD), data direction
(PTBDD), pullup enable (PTBPE), and slew rate control (PTBSE) registers. Refer to
I/O
When the ATD module is enabled, analog pin enables are used to specify which pins on port B will be used
as ATD inputs. Refer to
about using port B pins as ATD pins.
82
j
Controls,”
Controls,”
Port A
Port B
External Signal Description
Connections,” for available parallel I/O pins. All of these pins are available for general-purpose
Port A and Keyboard Interrupts
Port B and Analog to Digital Converter Inputs
for more information about general-purpose I/O control.
for more information about general-purpose I/O control.
for more information about using port A pins as keyboard interrupts pins.
MCU Pin:
MCU Pin:
Chapter 14, “Analog-to-Digital Converter
KBIP7
PTB7/
PTA7/
ADP7
Bit 7
Bit 7
MC9S08GT16A/GT8A Data Sheet, Rev. 1
KBIP6
PTB6/
PTA6/
ADP6
Figure 6-2. Port A Pin Names
Figure 6-3. Port B Pin Names
6
6
KBIP5
PTB5/
PTA5/
ADP5
5
5
KBIP4
PTA4/
PTB4/
ADP4
4
4
KBIP3
PTB3/
PTA3/
ADP3
3
3
(S08ATDV3),”
Chapter 7, “Keyboard Interrupt
KBIP2
PTB2/
PTA2/
ADP2
2
2
for more information
KBIP1
PTB1/
PTA1/
ADP1
Section 6.3, “Parallel
Section 6.3, “Parallel
Freescale Semiconductor
1
1
KBIP0
PTB0/
PTA0/
ADP0
Bit 0
Bit 0
Chapter 2,