MC908GR8CDWE Datasheet, PDF (227/408 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

Freescale Semiconductor, Inc.
Input/Output Ports (I/O)
Port E
READ DDRE ($000C)
WRITE DDRE ($000C)
RESET
WRITE PTE ($0008)
READ PTE ($0008)
DDREx
PTEx
PTEx
Figure 16-19. 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 16-6 summarizes
the operation of the port E pins.
Table 16-6. Port E Pin Functions
DDRE Bit PTE Bit I/O Pin Mode
Accesses to DDRE
Read/Write
0
X⁽¹⁾
Input, Hi-Z⁽²⁾
DDRE1–DDRE0
1
X
Output
DDRE1–DDRE0]
Notes:
1. X = Don’t care
2. Hi-Z = High impedance
3. Writing affects data register, but does not affect input.
Accesses to PTE
Read
Write
Pin
PTE1–PTE0⁽³⁾
PTE1–PTE0
PTE1–PTE0
MC68HC908GR8 — Rev 4.0
MOTOROLA
Input/Output Ports (I/O)
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Technical Data
227