MC68HC908LJ12 Datasheet, PDF (354/413 Pages) Freescale Semiconductor, Inc – 8-bit microcontroller units

Input/Output (I/O) Ports
KBI[7:4] — Keyboard Interrupt Pins
KBI[7:4] are input pins to the keyboard interrupt module. The
corresponding control bits, KBIE[7:4], in the keyboard interrupt enable
register, KBIER, select which port pins will be used as a keyboard
interrupt input and overrides any control from the port I/O logic. See
Section 19. Keyboard Interrupt Module (KBI)
17.6.2 Data Direction Register D (DDRD)
Data direction register D determines whether each port D pin is an input
or an output. Writing a logic 1 to a DDRD bit enables the output buffer for
the corresponding port D pin; a logic 0 disables the output buffer.
NOTE:
For those devices packaged in a 52-pin LQFP, PTD0–PTD7 are not
connected. DDRD0–DDRD7 should be set to a 1 to configure
PTD0–PTD7 as outputs.
Address: $0007
Bit 7
6
5
4
3
2
1
Read:
DDRD7
Write:
DDRD6
DDRD5
DDRD4
DDRD3
DDRD2
DDRD1
Reset: 0
0
0
0
0
0
0
Figure 17-13. Data Direction Register D (DDRD)
Bit 0
DDRD0
0
DDRD[7:0] — Data Direction Register D Bits
These read/write bits control port D data direction. Reset clears
DDRD[7:0], configuring all port D pins as inputs.
1 = Corresponding port D pin configured as output
0 = Corresponding port D pin configured as input
NOTE:
Avoid glitches on port D pins by writing to the port D data register before
changing data direction register D bits from 0 to 1. Figure 17-14 shows
the port D I/O logic.
MC68HC908LJ12 — Rev. 2.1
Freescale Semiconductor
Input/Output (I/O) Ports
Technical Data
355