Pin Functions
MC68HC908GR60A MC68HC908GR48A MC68HC908GR32A Data Sheet, Rev. 5
Freescale Semiconductor
27
VREFL is the low reference supply for the ADC, and by default the VSSAD/VREFL pin should be connected
1.5.8 Port A Input/Output (I/O) Pins (PTA7/KBD7/AD15–PTA0/KBD0/AD8)
PTA7–PTA0 are general-purpose, bidirectional I/O port pins. Any or all of the port A pins can be
programmed to serve as keyboard interrupt pins or used as analog-to-digital inputs. PTA7–PTA4 are only
These port pins also have selectable pullups when configured for input mode. The pullups are disengaged
when configured for output mode. The pullups are selectable on an individual port bit basis.
1.5.9 Port B I/O Pins (PTB7/AD7–PTB0/AD0)
PTB7–PTB0 are general-purpose, bidirectional I/O port pins that can also be used for analog-to-digital
converter (ADC) inputs. PTB7–PTB6 are only available on the 48-pin LQFP and 64-pin QFP packages.
1.5.10 Port C I/O Pins (PTC6–PTC0)
PTC6 and PTC5 are general-purpose, bidirectional I/O port pins.
PTC4–PTC0 are general-purpose, bidirectional I/O port pins that contain higher current sink/source
capability. PTC6–PTC2 are only available on the 48-pin LQFP and 64-pin QFP packages. See
ChapterThese port pins also have selectable pullups when configured for input mode. The pullups are disengaged
when configured for output mode. The pullups are selectable on an individual port bit basis.
1.5.11 Port D I/O Pins (PTD7/T2CH1–PTD0/SS)
PTD7–PTD0 are special-function, bidirectional I/O port pins. PTD3–PTD0 can be programmed to be
serial peripheral interface (SPI) pins, while PTD7–PTD4 can be individually programmed to be timer
interface module (TIM1 and TIM2) pins. PTD0 can be used to output a clock, MCLK. PTD7 is only
These port pins also have selectable pullups when configured for input mode. The pullups are disengaged
when configured for output mode. The pullups are selectable on an individual port bit basis.
1.5.12 Port E I/O Pins (PTE5–PTE2, PTE1/RxD, and PTE0/TxD)
PTE5–PTE0 are general-purpose, bidirectional I/O port pins. PTE1 and PTE0 can also be programmed
to be enhanced serial communications interface (ESCI) pins. PTE5–PTE2 are only available on the
1.5.13 Port F I/O Pins (PTF7/T2CH5–PTF0)
PTF7–PTF4 are special-function, bidirectional I/O port pins that can be individually programmed to be
timer interface module (TIM2) pins.