MC908QL4 FREESCALE [Freescale Semiconductor, Inc], MC908QL4 Datasheet - Page 112

• Manufacturer Part Number: MC908QL4
• Description: M68HC08 Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Input/Output Ports (PORTS)
12.3.1 Port A Data Register
The port A data register (PTA) contains a data latch for each of the six port A pins.
PTA[5:0] — Port A Data Bits
AWUL — Auto Wakeup Latch Data Bit
12.3.2 Data Direction Register A
Data direction register A (DDRA) determines whether each port A pin is an input or an output. Writing a
1 to a DDRA bit enables the output buffer for the corresponding port A pin; a 0 disables the output buffer.
DDRA[5:0] — Data Direction Register A Bits
Figure 12-3
112
These read/write bits are software programmable. Data direction of each port A pin is under the control
of the corresponding bit in data direction register A. Reset has no effect on port A data.
This is a read-only bit which has the value of the auto wakeup interrupt request latch. The wakeup
request signal is generated internally (see
port nor any of the associated bits such as PTA6 data register, pullup/down enable or direction.
These read/write bits control port A data direction. Reset clears DDRA[5:0], configuring all port A pins
as inputs.
1 = Corresponding port A pin configured as output
0 = Corresponding port A pin configured as input
shows the port A I/O logic.
Reset:
Reset:
Read:
Write:
Read:
Write:
Avoid glitches on port A pins by writing to the port A data register before
changing data direction register A bits from 0 to 1.
Bit 7
Bit 7
R
R
R
R
0
Figure 12-2. Data Direction Register A (DDRA)
= Reserved
= Reserved
AWUL
Figure 12-1. Port A Data Register (PTA)
R
6
6
0
MC68HC908QL4 Data Sheet, Rev. 7
DDRA5
PTA5
5
5
0
Chapter 4 Auto Wakeup Module
DDRA4
Unaffected by reset
PTA4
NOTE
4
4
0
= Unimplemented
= Unimplemented
DDRA3
PTA3
3
3
0
PTA2
2
2
0
0
DDRA1
PTA1
1
1
0
(AWU)). There is no PTA6
Freescale Semiconductor
DDRA0
PTA0
Bit 0
Bit 0
0