Datasheet

Input/Output (I/O) Ports
Port C
MC68HC908LJ24/LK24 — Rev. 2.1 Data Sheet
Freescale Semiconductor Input/Output (I/O) Ports 389
When DDRCx is a logic 1, reading address $0002 reads the PTCx data
latch. When DDRCx is a logic 0, reading address $0002 reads the
voltage level on the pin. The data latch can always be written, regardless
of the state of its data direction bit.
Table 18-4 summarizes the operation of the port C pins.
18.5.3 Port C LED Control Register (LEDC)
Port-C LED control register (LEDC) controls the direct LED drive
capability on PTC7–PTC0 pins. Each bit is individually configurable and
requires that the data direction register, DDRC, bit be configured as an
output.
LEDC[7:0] — Port C 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 C pin is configured for direct LED drive,
with 15mA current sinking capability
0 = Corresponding port C pin is configured for standard drive
Table 18-4. Port C Pin Functions
DDRC
Bit
PTC Bit I/O Pin Mode
Accesses to DDRC Accesses to PTC
Read/Write Read Write
0X
(1)
Notes:
1. X = don’t care.
Input, Hi-Z
(2)
2. Hi-Z = high impedance.
DDRC[7:0] Pin PTC[7:0]
(3)
3. Writing affects data register, but does not affect input.
1 X Output DDRC[7:0] PTC[7:0] PTC[7:0]
Address: $000D
Bit 7654321Bit 0
Read:
LEDC7 LEDC6 LEDC5 LEDC4 LEDC3 LEDC2 LEDC1 LEDC0
Write:
Reset:00000000
Figure 18-12. Port C LED Control Register (LEDC)