Motorola 68HC12BC32 - Manual (Page 11)

11
PORTS AND CONNECTORS
LCD_PORT
The LCD_PORT interface is connected to the data bus and memory mapped to locations 270
– 27F hex assigned to CS7. For the standard display, address 270 is the Command register,
address 271 is the Data register.
The interface supports all OPTREX

DMC series displays in 8 bit bus mode with up to 80
characters and provides the most common pinout for a dual row rear mounted display
connector. Power, ground, and Vee are also available at the LCDPORT-1 connector.
+5V 2 1 GND
A0 4 3 LCD-Vee
LCD1 6 5 /RW
D9 8 7 D8
D11 10 9 D10
D13 12 11 D12
D15 14 13 D14
Command Register:$270
Data Register:
$271
LCD-Vee is supplied by U13 and is adjusted by the R18
Potentiometer (adjustable resistor).
See the file KEYLCD12.ASM for an example program using this
LCD connector.
LCD3 2 1 LCD2
4 3 LCD4
Additional lines can be used as enables for larger panels and
are mapped as:
LCD2 = $274 & $275 LCD4 = $27C & $27D
LCD3 = $278 & $279
KEYPAD
1 PS4
2 PS5
3 PS6
4 PS7
5 PP4
6 PP5
7 PP6
8 PP7
The KEYPAD connector is a passive 8-pin connector that can be used to
connect a 4 x 4 matrix (16 key) keypad device. The connector is mapped to
the HC12 I/O ports S and P. This interface is implemented as a software
keyscan. Pins PS4-7 are used as column drivers which are active low
outputs. Pins PP4-7 are used for row input and provide an idle hi condition
with internal pull-ups to provide active key detection under software control.
See the HC12 Technical Reference Manual for a full description of these pins and the file
KEYLCD12.ASM
for an example program using this connector.