MC9S08GB60A Datasheet, PDF (83/302 Pages) Freescale Semiconductor, Inc – HCS08 Microcontrollers

Chapter 6 Parallel Input/Output
6.2 Features
Parallel I/O features, depending on package choice, include:
• A total of 56 general-purpose I/O pins in seven ports (PTG0 is output only)
• High-current drivers on port C and port F pins
• Hysteresis input buffers
• Software-controlled pullups on each input pin
• Software-controlled slew rate output buffers
• Eight port A pins shared with KBI1
• Eight port B pins shared with ATD1
• Eight high-current port C pins shared with SCI2 and IIC1
• Eight port D pins shared with TPM1 and TPM2
• Eight port E pins shared with SCI1 and SPI1
• Eight high-current port F pins
• Eight port G pins shared with EXTAL, XTAL, and BKGD/MS
6.3 Pin Descriptions
The MC9S08GBxxA/GTxxA has a total of 56 parallel I/O pins (one is output only) in seven 8-bit ports
(PTA–PTG). Not all pins are bonded out in all packages. Consult the pin assignment in Chapter 2, “Pins
and Connections,” for available parallel I/O pins. All of these pins are available for general-purpose 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.
6.3.1 Port A and Keyboard Interrupts
Port A
Bit 7
MCU Pin:
PTA7/
KBI1P7
6
5
4
3
PTA6/ PTA5/ PTA4/ PTA3/
KBI1P6 KBI1P5 KBI1P4 KBI1P3
Figure 6-2. Port A Pin Names
2
PTA2/
KBI1P2
1
PTA1/
KBI1P1
Bit 0
PTA0/
KBI1P0
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 Section 6.4, “Parallel
I/O Controls,” for more information about general-purpose I/O control.
MC9S08GB60A Data Sheet, Rev. 2
Freescale Semiconductor
83