MC908AS60ACFU Datasheet, PDF (263/414 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

Port G
22.8 Port G
Port G is a 3-bit special function port that shares all of its pins with the keyboard interrupt module (KBD).
Note that Port G is only available on 64-pin package options.
22.8.1 Port G Data Register
The port G data register contains a data latch for each of the three port G pins.
Address:
Read:
Write:
Reset:
Alternative
Function:
$000A
Bit 7
0
R
R
6
5
4
3
2
0
0
0
0
PTG2
R
R
R
R
Unaffected by Reset
KBD2
= Reserved
Figure 22-20. Port G Data Register (PTG)
1
PTG1
KBD1
Bit 0
PTG0
KBD0
PTG[2:0] — Port G Data Bits
These read/write bits are software programmable. Data direction of each port G pin is under the control
of the corresponding bit in data direction register G. Reset has no effect on PTG[2:0].
KBD[2:0] — Keyboard Wakeup pins
The keyboard interrupt enable bits, KBIE[2:0], in the keyboard interrupt control register, enable the port
G pins as external interrupt pins (See Chapter 24 Keyboard Module (KBI)). Enabling an external
interrupt pin will override the corresponding DDRGx.
22.8.2 Data Direction Register G
Data direction register G determines whether each port G pin is an input or an output. Writing a logic 1 to
a DDRG bit enables the output buffer for the corresponding port G pin; a logic 0 disables the output buffer.
Address:
Read:
Write:
Reset:
$000E
Bit 7
6
5
4
3
2
1
0
0
0
0
0
DDRG2 DDRG1
R
R
R
R
R
0
0
0
0
0
0
0
R
= Reserved
Figure 22-21. Data Direction Register G (DDRG)
Bit 0
DDRG0
0
MC68HC908AZ60A • MC68HC908AS60A • MC68HC908AS60E Data Sheet, Rev. 6
Freescale Semiconductor
263