MC68HC908LJ12 Datasheet, PDF (349/413 Pages) Freescale Semiconductor, Inc – 8-bit microcontroller units

Input/Output (I/O) Ports
Table 17-3 summarizes the operation of the port B pins.
Table 17-3. Port B Pin Functions
DDRB
Bit
0
PTB Bit
X⁽¹⁾
I/O Pin Mode
Input, Hi-Z⁽²⁾
Accesses to DDRB
Read/Write
DDRB[7:0]
1
X
Output
DDRB[7:0]
Notes:
1. X = don’t care.
2. Hi-Z = high impedance.
3. Writing affects data register, but does not affect input.
Accesses to PTB
Read
Pin
Write
PTB[7:0]⁽³⁾
PTB[7:0] PTB[7:0]
17.4.3 Port B LED Control Register (LEDB)
The port-B LED control register (LEDB) controls the direct LED drive
capability on PTB5–PTB0 pins. Each bit is individually configurable and
requires that the data direction register, DDRB, bit be configured as an
output.
When the IRSCI is enabled, setting the LEDB0 bit also enables high
current (15mA) sink capability for the TxD pin.
Address: $000C
Bit 7
6
5
4
3
2
1
Read: 0
Write:
0
LEDB5 LEDB4 LEDB3 LEDB2 LEDB1
Reset: 0
0
0
0
0
0
0
Figure 17-8. Port B LED Control Register (LEDB)
Bit 0
LEDB0
0
LEDB[5:0] — Port B 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 B pin configured for direct LED drive:
15mA current sinking capability on PTB[1:0], and
8mA current sinking capability on PTB[5:2]
0 = Corresponding port B pin configured for standard drive
Technical Data
350
Input/Output (I/O) Ports
MC68HC908LJ12 — Rev. 2.1
Freescale Semiconductor