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 OPTREXDMC 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.

 

J3

LCD3

2

1

 

4

3

LCD2

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

1PH0

2PH1

3PH2

4PH3

5PH4

6PH5

7PH6

8PH7

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.

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Motorola DG128, 68HC912D60, CMD912x, DT128 manual Lcdport, Keypad