mc68hc908qy4vp Freescale Semiconductor, Inc, mc68hc908qy4vp Datasheet - Page 100

• Manufacturer Part Number: mc68hc908qy4vp
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Input/Output Ports (PORTS)
PTAPUE[5:0] — Port A Input Pullup Enable Bits
12.3 Port B
Port B is an 8-bit general purpose I/O port. Port B is only available on the MC68HC908QY1,
MC68HC908QY2, and MC68HC908QY4.
12.3.1 Port B Data Register
The port B data register (PTB) contains a data latch for each of the eight port B pins.
PTB[7:0] — Port B Data Bits
100
Table 12-1
1. X = don’t care
2. I/O pin pulled to V
3. Writing affects data register, but does not affect input.
4. Hi-Z = high impedance
5. Output does not apply to PTA2
PTAPUE
These read/write bits are software programmable to enable pullup devices on port A pins.
These read/write bits are software programmable. Data direction of each port B pin is under the control
of the corresponding bit in data direction register B. Reset has no effect on port B data.
Bit
X
1
0
1 = Corresponding port A pin configured to have internal pull if its DDRA bit is set to 0
0 = Pullup device is disconnected on the corresponding port A pin regardless of the state of its
DDRA bit
summarizes the operation of the port A pins.
Address: $0001
DDRA
Reset:
Read:
Write:
Bit
0
0
1
DD
by internal pullup.
PTB7
Bit 7
PTA
X
Bit
X
X
(1)
Figure 12-5. Port B Data Register (PTB)
PTB6
MC68HC908QY/QT Family Data Sheet, Rev. 5
6
Input, V
Input, Hi-Z
Table 12-1. Port A Pin Functions
I/O Pin
Output
Mode
DD
PTB5
(2)
(4)
5
Unaffected by reset
PTB4
Accesses to DDRA
4
DDRA5–DDRA0
DDRA5–DDRA0
DDRA5–DDRA0
Read/Write
PTB3
3
PTB2
2
PTA5–PTA0
PTB1
Read
Pin
Pin
1
Accesses to PTA
Freescale Semiconductor
PTB0
Bit 0
PTA5–PTA0
PTA5–PTA0
PTA5–PTA0
Write
(3)
(3)
(5)