mcf51ac256a Freescale Semiconductor, Inc, mcf51ac256a Datasheet - Page 111

• Manufacturer Part Number: mcf51ac256a
• Description: Mcf51ac Flexis
• Manufacturer: Freescale Semiconductor, Inc

6.5.2.1
6.5.2.2
Freescale Semiconductor
Reset:
Reset:
PTBDDn
PTBDn
Field
Field
7–0
7–0
W
W
R
R
PTBDD7
PTBD7
Port B Data Register Bits — For port B pins that are inputs, reads return the logic level on the pin. For port B
pins that are configured as outputs, reads return the last value written to this register.
Writes are latched into all bits of this register. For port B pins that are configured as outputs, the logic level is
driven out the corresponding MCU pin.
Reset forces PTBD to all 0s, but these 0s are not driven out the corresponding pins because reset also configures
all port pins as high-impedance inputs with pullups/pulldowns disabled.
Data Direction for Port B Bits — These read/write bits control the direction of port B pins and what is read for
PTBD reads.
0 Input (output driver disabled) and reads return the pin value.
1 Output driver enabled for port B bit n and PTBD reads return the contents of PTBDn.
Port B Data Register (PTBD)
0
Port B Data Direction Register (PTBDD)
0
7
7
MCF51AC256 ColdFire Integrated Microcontroller Reference Manual, Rev. 5
PTBDD6
PTBD6
0
0
6
6
Figure 6-8. Port B Data Direction Register (PTBDD)
Table 6-7. PTBDD Register Field Descriptions
Table 6-6. PTBD Register Field Descriptions
Figure 6-7. Port B Data Register (PTBD)
PTBDD5
PTBD5
0
0
5
5
PTBDD4
PTBD4
0
0
4
4
Description
Description
PTBDD3
PTBD3
3
0
3
0
PTBDD2
PTBD2
0
0
2
2
Parallel Input/Output Control
PTBDD1
PTBD1
0
0
1
1
PTBDD0
PTBD0
0
0
0
0
6-7