mc68hc912bc32 Freescale Semiconductor, Inc, mc68hc912bc32 Datasheet - Page 86

• Manufacturer Part Number: mc68hc912bc32
• Description: M68hc12 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Bus Control and Input/Output (I/O)
be set. In this special case of expanded mode and EME set, the port E data register (PORTE) and port E
data direction register (DDRE) are removed from the on-chip memory map and become external
accesses so port E may be rebuilt externally.
6.3.1 Port A Data Register
Read: Anytime, if register is in the map
Write: Anytime, if register is in the map
Bits PA7–PA0 are associated with addresses ADDR15–ADDR8 and DATA15–DATA8. When this port is
not used for external addresses and data, such as in single-chip mode, these pins can be used as
general-purpose input/output (I/O). DDRA determines the primary direction of each pin. This register is
not in the on-chip map in expanded and peripheral modes.
6.3.2 Port A Data Direction Register
Read: Anytime, if register is in the map
Write: Anytime, if register is in the map
This register determines the primary direction for each port A pin when functioning as a general-purpose
I/O port. DDRA is not in the on-chip map in expanded and peripheral modes.
86
Expanded wide and peripheral:
1 = Associated pin is an output.
0 = Associated pin is a high-impedance input.
Address: $0002
Expanded narrow:
Reset:
Read:
Write:
Address: $0000
Reset:
Read:
Write:
DDA7
Bit 7
0
Figure 6-2. Port A Data Direction Register (DDRA)
DATA15/7
ADDR15
ADDR15
DATA15
Bit 7
PA7
Figure 6-1. Port A Data Register (PORTA)
DDA6
6
0
M68HC12B Family Data Sheet, Rev. 9.1
DATA14/6
ADDR14
ADDR14
DATA14
PA6
6
DDA5
5
0
DATA13/5
ADDR13
ADDR13
DATA13
PA5
5
DDA4
4
0
DATA12/4
ADDR12
ADDR12
DATA12
Unaffected by reset
PA4
4
DDA3
3
0
DATA11/3
ADDR11
ADDR11
DATA11
PA3
DDA2
3
2
0
DATA10/2
ADDR10
ADDR10
DATA10
PA2
DDA1
2
1
0
DATA9/1
Freescale Semiconductor
ADDR9
ADDR9
DATA9
PA1
DDA0
1
Bit 0
0
DATA8/0
ADDR8
ADDR8
DATA8
Bit 0
PA0