
Chapter 6 Parallel Input/Output
MC9S08GB/GT Data Sheet, Rev. 2.3
80
Freescale Semiconductor
Port A can be configured to be keyboard interrupt input pins. Refer to
Chapter 9, “Keyboard Interrupt
(KBI) Module
,”
for more information about using port A pins as keyboard interrupts pins.
6.3.2
Port B and Analog to Digital Converter Inputs
Figure 6-3. Port B Pin Names
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),pullupenable(PTBPE),andslewratecontrol(PTBSE)registers.Referto
Section 6.4,“Parallel
I/O Controls
,”
for more information about general-purpose I/O control.
WhentheATDmoduleisenabled,analogpinenablesareusedtospecifywhichpinsonportBwillbeused
as ATD inputs. Refer to
Chapter 14, “Analog-to-Digital Converter (ATD) Module
,”
for more information
about using port B pins as ATD pins.
6.3.3
Port C and SCI2, IIC, and High-Current Drivers
Figure 6-4. Port C Pin Names
Port C is an 8-bit port which is shared among the SCI2 and IIC1 modules, and general-purpose I/O. When
SCI2 or IIC1 modules are enabled, the pin direction will be controlled by the module or function. Port C
has high current output drivers.
Port C pins are available as general-purpose I/O pins controlled by the port C data (PTCD), data direction
(PTCDD),pullupenable(PTCPE),andslewratecontrol(PTCSE)registers.Referto
Section 6.4,“Parallel
I/O Controls
,”
for more information about general-purpose I/O control.
When the SCI2 module is enabled, PTC0 serves as the SCI2 module’s transmit pin (TxD2) and PTC1
serves as the receive pin (RxD2). Refer to
Chapter 11, “Serial Communications Interface (SCI) Module
,”
for more information about using PTC0 and PTC1 as SCI pins
When the IIC module is enabled, PTC2 serves as the IIC modules’s serial data input/output pin (SDA1)
and PTC3 serves as the clock pin (SCL1). Refer to
Chapter 13, “Inter-Integrated Circuit (IIC) Module
,”
for more information about using PTC2 and PTC3 as IIC pins.
Port B
Bit 7
6
5
4
3
2
1
Bit 0
MCU Pin:
PTB7/
AD1P7
PTB6/
AD1P6
PTB5/
AD1P5
PTB4/
AD1P4
PTB3/
AD1P3
PTB2/
AD1P2
PTB1/
AD1P1
PTB0/
AD1P0
Port C
Bit 7
6
5
3
3
2
1
Bit 0
MCU Pin:
PTC7
PTC6
PTC5
PTC4
PTC3/
SCL1
PTC2/
SDA1
PTC1/
RxD2
PTC0/
TxD2