MC68HC05JJ6 Datasheet, PDF (102/216 Pages) Freescale Semiconductor, Inc – General Release Specification Microcontrollers

Parallel Input/Output
Table 7-4. Port C Pin Functions (MC68HC05JP6)
Control Bits
Port C
Pin(s)
Mask
Option
Pull-
down
Inhibit
PDICH
Port C
PDICL
Low Nibble
0
X
0
PC0
0
X
1
PC1
PC2
1
X
X
PC3
X
X
X
High Nibble
0
0
X
PC4
0
1
X
PC5
PC6
1
X
X
PC7
X
X
X
* DDRC can always be read or written.
X = Don’t Care
PORTC Access
(Pin or Data Register)
Result on
Port C Pins
DDRCn*
0
0
0
1
0
0
0
1
Read
PIN
PIN
PIN
DATA
PIN
PIN
PIN
DATA
Write Pulldown
Pin
DATA
DATA
DATA
DATA
DATA
DATA
DATA
DATA
ON
OFF
OFF
OFF
ON
OFF
OFF
OFF
PCn IN
PCn IN
PCn IN
PCn OUT
PCn IN
PCn IN
PCn IN
PCn OUT
7.6 Port Transitions
Glitches and temporary floating inputs can occur if the control bits
regarding each port I/O pin are not performed in the correct sequence.
• Do not use read-modify-write instructions on pulldown register A
or B.
• Avoid glitches on port pins by writing to the port data register
before changing data direction register bits from a logic zero to a
logic one.
• Avoid a floating port input by clearing its pulldown register bit
before changing its data direction register bit from a logic one to a
logic zero.
• A mask option turns off all port pulldown devices and disables
software control of the pulldown devices. Reset has no effect on
the pulldown devices if they are not selected by mask option.
General Release Specification
102
MC68HC05JJ6/MC68HC05JP6 — Rev. 3.2
Parallel Input/Output
Freescale Semiconductor