MC68HC908GT16_07 FREESCALE [Freescale Semiconductor, Inc], MC68HC908GT16_07 Datasheet - Page 131

• Manufacturer Part Number: MC68HC908GT16_07
• Description: Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

When bit DDRCx is a 1, reading address $0002 reads the PTCx data latch. When bit DDRCx is a 0,
reading address $0002 reads the voltage level on the pin. The data latch can always be written,
regardless of the state of its data direction bit.
12.4.3 Port C Input Pullup Enable Register
The port C input pullup enable register (PTCPUE) contains a software configurable pullup device for each
of the seven port C pins. Each bit is individually configurable and requires that the data direction register,
DDRC, bit be configured as an input. Each pullup is automatically and dynamically disabled when a port
bit’s DDRC is configured for output mode.
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
PTCPUE
Bit
X
1
0
Address:
DDRC
Reset:
Read:
Write:
Bit
0
0
1
MC68HC908GT16 • MC68HC908GT8 • MC68HC08GT16 Data Sheet, Rev. 5.0
Figure 12-12. Port C Input Pullup Enable Register (PTCPUE)
DD
READ DDRC ($0006)
WRITE DDRC ($0006)
WRITE PTC ($0002)
READ PTC ($0002)
$000E
Bit 7
by internal pullup device.
0
0
PTC
X
Bit
X
X
(1)
= Unimplemented
PTCPUE6
6
0
Input, Hi-Z
Input, V
RESET
Table 12-4. Port C Pin Functions
Figure 12-11. Port C I/O Circuit
I/O Pin
Output
Mode
PTCPUE5
DD
(2)
(4)
5
0
Table 12-4
PTCPUE4
DDRCx
Accesses to DDRC
PTCx
DDRC6–DDRC0
DDRC6–DDRC0
DDRC6–DDRC0
4
0
Read/Write
PTCPUE3
summarizes the operation of the port C pins.
3
0
PTCPUE2
2
0
PTCPUEx
PTC6–PTC0
Read
Pin
Pin
PTCPUE1
Accesses to PTC
1
0
V
DD
45 k
PTCPUE0
PTCx
Bit 0
0
PTC6–PTC0
PTC6–PTC0
PTC6–PTC0
Write
Port C
(3)
(3)
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