MC68HC908BD48 Datasheet, PDF (249/290 Pages) Freescale Semiconductor, Inc – Microcontrollers

Input/Output (I/O) Ports
Port E
READ DDRE ($0009)
WRITE DDRE ($0009)
RESET
WRITE PTE ($0008)
READ PTE ($0008)
DDREx
PTEx
PTEx
Figure 17-18. 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 17-7 summarizes
the operation of the port E pins.
Table 17-7. Port E Pin Functions
DDRE Bit
0
PTE Bit
X⁽¹⁾
I/O Pin Mode
Input, Hi-Z⁽²⁾
Accesses to DDRE
Read/Write
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
Pin
Write
PTE1–PTE0⁽³⁾
PTE1–PTE0
PTE1–PTE0
MC68HC908BD48 — Rev. 1.0
MOTOROLA
Input/Output (I/O) Ports
Technical Data
249