MC68HC908LJ12CPB FREESCALE [Freescale Semiconductor, Inc], MC68HC908LJ12CPB Datasheet - Page 345

• Manufacturer Part Number: MC68HC908LJ12CPB
• Description: 8-bit microcontroller units
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Input/Output (I/O) Ports
Technical Data
346
When DDRAx is a logic 1, reading address $0000 reads the PTAx data
latch. When DDRAx is a logic 0, reading address $0000 reads the
voltage level on the pin. The data latch can always be written, regardless
of the state of its data direction bit.
Table 17-2
Notes:
1. X = don’t care.
2. Hi-Z = high impedance.
3. Writing affects data register, but does not affect input.
DDRA
Bit
0
1
READ DDRA ($0004)
WRITE DDRA ($0004)
WRITE PTA ($0000)
READ PTA ($0000)
PTA Bit
X
summarizes the operation of the port A pins.
X
(1)
Input/Output (I/O) Ports
Table 17-2. Port A Pin Functions
Input, Hi-Z
I/O Pin Mode
Figure 17-4. Port A I/O Circuit
RESET
Output
(2)
Accesses to DDRA
DDRAx
PTAx
DDRA[7:0]
DDRA[7:0]
Read/Write
MC68HC908LJ12
Freescale Semiconductor
PTA[7:0]
Read
Pin
Accesses to PTA
PTA[7:0]
PTA[7:0]
—
Write
Rev. 2.1
PTAx
(3)