Motorola DG128 User Manual

LCD_PORT

The LCD_PORT interface is connected to the data bus and memory mapped into the Register
Following memory area of the HC12.  Note that the DP256 does not support the LCD Port due
to no Register following area is available. Refer to the PM12xxx board memory map for LCd
Port address location. For the standard display, the base address of the LCD Port is the
Command register and the Base+1 address is the display 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 this 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: LCD PORT Base+0
Data Register:

LCD PORT Base +1

LCD-Vee is supplied by U16 and is adjusted by the CONTRAST
Potentiometer (adjustable resistor).

See the file  KLCD12Dx.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 character
panels and are mapped as:

LCD2 = Base +$4 & $5

LCD4 = Base + $C & $D

LCD3 = Base +$8 & $9

Note: These selects can also be used for peripheral controls.

KEYPAD

PH0

PH1

PH2

PH3

PH4

PH5

PH6

PH7

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 HC12 I/O port H.  This interface is implemented as a software
keyscan.  Pins PH0-3 are used as column drivers which are active high
outputs. Pins PH4-7 are used for row input and will read high when their
row is high.

See the file KLCD12Dx.ASM  for an example program using this
connector.