mc9s12xd256 Freescale Semiconductor, Inc, mc9s12xd256 Datasheet - Page 922

• Manufacturer Part Number: mc9s12xd256
• Description: Hcs12x Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Chapter 23 DQ256 Port Integration Module (S12XDQ256PIMV2)
23.0.5.4
Read: Anytime. In emulation modes, read operations will return the data from the external bus, in all other
modes the data source is depending on the data direction value.
Write: Anytime. In emulation modes, write operations will also be directed to the external bus.
23.0.5.5
Read: Anytime. In emulation modes, read operations will return the data from the external bus, in all other
modes the data source is depending on the data direction value.
Write: Anytime. In emulation modes, write operations will also be directed to the external bus.
922
DDRA[7:0]
DDRB[7:0]
Reset
Reset
Field
Field
7–0
7–0
W
W
R
R
DDRB7
Data Direction Port A — This register controls the data direction for port A. When Port A is operating as a general
purpose I/O port, DDRA determines whether each pin is an input or output. A logic level “1” causes the
associated port pin to be an output and a logic level “0” causes the associated pin to be a high-impedance input.
0 Associated pin is configured as input.
1 Associated pin is configured as output.
Note: Due to internal synchronization circuits, it can take up to 2 bus clock cycles until the correct value is read
Data Direction Port B — This register controls the data direction for port B. When Port B is operating as a general
purpose I/O port, DDRB determines whether each pin is an input or output. A logic level “1” causes the
associated port pin to be an output and a logic level “0” causes the associated pin to be a high-impedance input.
0 Associated pin is configured as input.
1 Associated pin is configured as output.
Note: Due to internal synchronization circuits, it can take up to 2 bus clock cycles until the correct value is read
PC7
Port B Data Direction Register (DDRB)
Port C Data Register (PORTC)
0
0
7
7
on PORTA after changing the DDRA register.
on PORTB after changing the DDRB register.
DDRB6
PC6
0
0
6
6
Figure 23-6. Port B Data Direction Register (DDRB)
Figure 23-7. Port C Data Register (PORTC)
Table 23-6. DDRA Field Descriptions
Table 23-7. DDRB Field Descriptions
DDRB5
MC9S12XDP512 Data Sheet, Rev. 2.17
PC5
0
0
5
5
DDRB4
PC4
0
0
4
4
Description
Description
DDRB3
PC3
0
0
3
3
DDRB2
PC2
0
0
2
2
DDRB1
Freescale Semiconductor
PC1
0
0
1
1
DDRB0
PC0
0
0
0
0