Datasheet

Chapter 6 Parallel Input/Output
MC9S08AC16 Series Data Sheet, Rev. 9
102 Freescale Semiconductor
6.7.11 Port F I/O Registers (PTFD and PTFDD)
Port F parallel I/O function is controlled by the registers listed below.
76543210
R
R PTFD6 PTFD5 PTFD4 R R PTFD1 PTFD0
W
Reset00000000
Figure 6-35. Port F Data Register (PTFD)
1
1
Bits 7, 3 and 2 are reserved bits that must always be written to 0.
Table 6-26. PTFD Register Field Descriptions
Field Description
6:4, 1:0
PTFDn
Port F Data Register Bits— For port F pins that are inputs, reads return the logic level on the pin. For port F
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 F pins that are configured as outputs, the logic level is
driven out the corresponding MCU pin.
Reset forces PTFD 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.
76543210
R
R PTFDD6 PTFDD5 PTFDD4 R R PTFDD1 PTFDD0
W
Reset00000000
Figure 6-36. Data Direction for Port F (PTFDD)
1
1
Bits 7, 3 and 2 are reserved bits that must always be written to 0.
Table 6-27. PTFDD Register Field Descriptions
Field Description
6:4, 1:0
PTFDDn
Data Direction for Port F Bits — These read/write bits control the direction of port F pins and what is read for
PTFD reads.
0 Input (output driver disabled) and reads return the pin value.
1 Output driver enabled for port F bit n and PTFD reads return the contents of PTFDn.