MC68HC908GZ8 Datasheet, PDF (215/344 Pages) Motorola, Inc – Microcontrollers

Input/Output (I/O) Ports
Port E
READ DDRE ($000C)
WRITE DDRE ($000C)
RESET
WRITE PTE ($0008)
DDREx
PTEx
PTEx
READ PTE ($0008)
Figure 17-19. 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 17-6 summarizes the operation of the port E pins.
Table 17-6. Port E Pin Functions
DDRE PTE
Bit
Bit
I/O Pin
Mode
Accesses
to DDRE
Read/Write
0
X⁽¹⁾
Input, Hi-Z⁽²⁾
DDRE5–DDRE0
1
X
Output
DDRE5–DDRE0
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
PTE5–PTE0⁽³⁾
PTE5–PTE0
PTE5–PTE0
MC68HC908GZ8
Freescale Semiconductor
Input/Output (I/O) Ports
Data Sheet
215