Datasheet

Input/Output (I/O) Ports
Data Sheet MC68HC908LJ24/LK24 — Rev. 2.1
396 Input/Output (I/O) Ports Freescale Semiconductor
When DDREx is a logic 1, reading address $0008 reads the PTEx data
latch. When 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 18-6 summarizes the operation of the port E pins.
18.7.3 Port E LED Control Register (LEDE)
The port-E LED control register (LEDE) controls the direct LED drive
capability on PTE7–PTE0 pins. Each bit is individually configurable and
requires that the data direction register, DDRE, bit be configured as an
output.
LEDE[7:0] — Port E LED Drive Enable Bits
These read/write bits are software programmable to enable the direct
LED drive on an output port pin.
1 = Corresponding port E pin is configured for direct LED drive,
with 15mA current sinking capability
0 = Corresponding port E pin is configured for standard drive
Table 18-6. Port E Pin Functions
DDRE
Bit
PTE Bit I/O Pin Mode
Accesses to DDRE Accesses to PTE
Read/Write Read Write
0X
(1)
Notes:
1. X = don’t care; except.
Input, Hi-Z
(2)
2. Hi-Z = high impedance.
DDRE[7:0] Pin PTE[7:0]
(3)
3. Writing affects data register, but does not affect input.
1 X Output DDRE[7:0] PTE[7:0] PTE[7:0]
Address: $000E
Bit 7654321Bit 0
Read:
LEDE7 LEDE6 LEDE5 LEDE4 LEDE3 LEDE2 LEDE1 LEDE0
Write:
Reset:00000000
Figure 18-19. Port E LED Control Register (LEDE)