
Parallel Input/Output
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
84
Freescale Semiconductor
6.6.5
Port E Registers (PTED, PTEPE, and PTEDD)
Port E pins used as general-purpose I/O pins are controlled by the port E data (PTED), data direction
(PTEDD), and pullup enable (PTEPE) registers.
76543210
R
W
Reset
00000000
Figure 6-18. Port E Data Register (PTED)
Table 6-13. PTED Field Descriptions
Field
Description
7:0
PTED[7:0]
Port E Data Register Bits — For port E pins that are inputs, reads return the logic level on the pin. For port E
pins that are congured as outputs, reads return the last value written to this register.
Writes are latched into all bits of this register. For port E pins that are congured as outputs, the logic level is
driven out the corresponding MCU pin.
Reset forces PTED to all 0s, but these 0s are not driven out the corresponding pins because reset also congures
all port pins as high-impedance inputs with pullups disabled.
76543210
R
W
Reset
00000000
Figure 6-19. Pullup Enable for Port E (PTED)
Table 6-14. PTED Field Descriptions
Field
Description
7:0
PTED[7:0]
Pullup Enable for Port E Bits — For port E pins that are inputs, these read/write control bits determine whether
internal pullup devices are enabled. For port E pins that are congured as outputs, these bits are ignored and
the internal pullup devices are disabled.
0 Internal pullup device disabled.
1 Internal pullup device enabled.