MC68HC908JB8 Datasheet, PDF (216/286 Pages) Motorola, Inc – MICROCONTROLLERS

Input/Output Ports (I/O)
READ DDRE ($000C)
WRITE DDRE ($000C)
RESET
WRITE PTE ($0008)
DDREx
PTEx
PTEx
READ PTE ($0008)
Figure 12-16. 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 12-4 summarizes
the operation of the port E pins.
Table 12-6. Port E Pin Functions
DDRE
Bit
0
1
Accesses
PTE
Bit
I/O Pin Mode ^{to DDRE}
Accesses to PTE
Read/Write Read
Write
X⁽¹⁾
Input, Hi-Z^{(2) DDRE[4:0]}
Pin
PTE[4:0]⁽³⁾
X
Output
DDRE[4:0] PTE[4:0] PTE[4:0]
NOTES:
1. X = don’t care.
2. Hi-Z = high impedance.
3. Writing affects data register, but does not affect input.
12.8 Port Options
All pins of port A, port B, port C, and port E have programmable pullup
resistors. Port pins PTD5–PTD0 have LED drive capability. Port pins
PTE4 and PTE3 have 10mA high current drive capability.
Technical Data
216
MC68HC908JB8•MC68HC08JB8•MC68HC08JT8 — Rev. 2.3
Input/Output Ports (I/O)
Freescale Semiconductor