MC908GR16ACFA FREESCALE [Freescale Semiconductor, Inc], MC908GR16ACFA Datasheet - Page 119

• Manufacturer Part Number: MC908GR16ACFA
• Description: M68HC08 Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Figure 12-4
When bit DDRAx is a 1, reading address $0000 reads the PTAx data latch. When bit DDRAx is a 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.
Freescale Semiconductor
1. X = Don’t care
2. I/O pin pulled up to V
3. Writing affects data register, but does not affect input.
4. Hi-Z = High impedance
PTAPUE
Bit
X
1
0
shows the port A I/O logic.
DDRA
Bit
0
0
1
DD
READ DDRA ($0004)
WRITE DDRA ($0004)
WRITE PTA ($0000)
READ PTA ($0000)
by internal pullup device
PTA
X
Bit
X
X
(1)
Input, Hi-Z
Input, V
MC68HC908GR16A Data Sheet, Rev. 1.0
Table 12-2. Port A Pin Functions
RESET
Figure 12-4. Port A I/O Circuit
I/O Pin
Output
Mode
DD
(2)
(4)
Table 12-2
DDRAx
Accesses to DDRA
PTAx
DDRA7–DDRA0
DDRA7–DDRA0
DDRA7–DDRA0
Read/Write
summarizes the operation of the port A pins.
PTAPUEx
PTA7–PTA0
Read
Pin
Pin
Accesses to PTA
V
DD
INTERNAL
PULLUP
DEVICE
PTAx
PTA7–PTA0
PTA7–PTA0
PTA7–PTA0
Write
Port A
(3)
(3)
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