mc9s08qd4 Freescale Semiconductor, Inc, mc9s08qd4 Datasheet - Page 72

• Manufacturer Part Number: mc9s08qd4
• Description: Hcs08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

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2
Chapter 6 Parallel Input/Output Control
6.4.1.2
6.4.2
The pins associated with port A are controlled by the registers in this section. These registers control the
pin pullup, slew rate and drive strength of the Port A pins independent of the parallel I/O register.
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PTADD[5:0]
PTAD[5:0]
PTADD5 has no effect on the input-only PTA5 pin. Read this bit is always equal to zero.
PTADD4 has no effect on the output-only PTA4 pin.
Reset:
Field
Field
5:0
5:0
W
R
Port A Control Registers
Port A Data Register Bits — For port A pins that are inputs, reads return the logic level on the pin. For port A
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 A pins that are configured as outputs, the logic level is
driven out the corresponding MCU pin.
Reset forces PTAD 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 disabled.
Data Direction for Port A Bits — These read/write bits control the direction of port A pins and what is read for
PTAD reads.
0 Input (output driver disabled) and reads return the pin value.
1 Output driver enabled for port A bit n and PTAD reads return the contents of PTADn.
Port A Data Direction (PTADD)
0
7
0
0
0
6
Figure 6-3. Port A Data Direction Register (PTADD)
Table 6-2. PTADD Register Field Descriptions
Table 6-1. PTAD Register Field Descriptions
MC9S08QD4 Series MCU Data Sheet, Rev. 3
PTADD5
0
5
1
PTADD4
0
4
Description
Description
2
PTADD3
3
0
PTADD2
0
2
PTADD1
Freescale Semiconductor
0
1
PTADD0
0
0