XC912BC32CFU8 Motorola Semiconductor Products, XC912BC32CFU8 Datasheet - Page 90

• Manufacturer Part Number: XC912BC32CFU8
• Description: M68HC12B Family Data Sheet
• Manufacturer: Motorola Semiconductor Products

Bus Control and Input/Output (I/O)
6.3.4 Port B Data Direction Register
6.3.5 Port E Data Register
Data Sheet
90
Alternate function:
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 B pin when functioning
as a general-purpose I/O port. DDRB is not in the on-chip map in expanded and
peripheral modes.
Read: Anytime, if register is in the map
Write: Anytime, if register is in the map
This register is associated with external bus control signals and interrupt inputs
including:
•
•
•
•
•
•
•
Address: $0003
Address: $0008
Reset:
Reset:
Read:
Write:
Read:
Write:
1 = Associated pin is an output.
0 = Associated pin is a high-impedance input.
Data bus enable (DBE)
Mode select (MODB/IPIPE1 and MODA/IPIPE0)
E clock
Data size (LSTRB/TAGLO)
Read/write (R/W)
IRQ
XIRQ
DDB7
DBE
Bit 7
Bit 7
PE7
Figure 6-5. Port E Data Register (PORTE)
0
0
Figure 6-4. Port B Data Direction Register (DDRB)
Bus Control and Input/Output (I/O)
MODB or
IPIPE1
DDB6
PE6
6
0
6
0
MODA or
IPIPE0
DDB5
PE5
5
0
5
0
DDB4
ECLK
PE4
4
0
4
0
LSTRB or
TAGLO
DDB3
PE3
3
0
3
0
M68HC12B Family — Rev. 8.0
DDB2
PE2
R/W
2
0
2
0
DDB1
PE1
IRQ
1
0
1
0
MOTOROLA
DDB0
XIRQ
Bit 0
Bit 0
PE0
0
0