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4-MULTIPLEXED LCD WITH A STANDARD ST62

The code uses DR_seg, DDR_seg and OR_seg labels to access the configuration registers of

the segments port. DR_com, DDR_com and OR_com labels are used for the commons port.

DR_seg_2

and DR_com_2 are labels referring to RAM variables used as shadow I/O port

Data Registers. These 8 labels are declared as external at the beginning of LCD_drv.st6.

Therefore, to make the library work, you must define them as synonyms of actual configura-

tion registers, like in the following example:

DDR_com

DATA

DDRB

DR_com

DATA

DRB

OR_com

DATA

ORB

DDR_seg

DATA

DDRA

DR_seg

DATA

DRA

OR_seg

DATA

ORA

DR_com_2

DATA

DRB_2

DR_seg_2

DATA

DRA_2

These definitions must be performed in another source file which is to be linked with

LCD_drv.st6

.

Note: in this example, DRA_2 and DRB_2 definitions must be in the same source file as

DR_seg_2

and DR_com_2 definitions, otherwise the DATA directive does not work.

Once the segments and commons ports defined, the MCU must be wired according to Figure

6. Note that a pair of S pins is assigned to each “8-segment digit”. To understand the roles of

each of the two pins, refer to Figure 6.