MC68HC08AS20 Datasheet, PDF (195/386 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

READ DDRE ($000C)
WRITE DDRE ($000C)
RESET
WRITE PTE ($0008)
DDREx
PTEx
PTEx
READ PTE ($0008)
Figure 15-15. Port E I/O Circuit
When bit DDREx is a logic 1, reading address $0008 reads the PTEx
data latch. When bit DDREx is a logic 0, reading address $0008 reads
the voltage level on the pin. The data latch can always be written,
regardless of the state of its data direction bit. Table 15-6 summarizes
the operation of the port E pins.
Table 15-6. Port E Pin Functions
DDRE
Bit
0
PTE
I/O Pin
Accesses
to DDRE
Accesses to PTE
Bit
Mode
Read/Write
Read
Write
X
Input, Hi-Z DDRE[7:0]
Pin
PTE[7:0]⁽¹⁾
1
X
Output
DDRE[7:0] PTE[7:0]
PTE[7:0]
X = don’t care
Hi-Z = high impedance
1. Writing affects data register, but does not affect input.
MC68HC08AS20 — Rev. 4.1
Freescale Semiconductor
Advance Information
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