Preliminary

AS2591

Rev. 1.0

Page 6

May 1999

LCD Symbols

Each symbol is associated with a fixed digit address. The circuit has 12 symbols implemented associated with the

lower 12 addresses.

Table 1: Symbol Overview

Enabled

Address

Name

Description

Always

y0

KL

Key lock activated

Optional

y1

SP

Loudspeaker on

Always

y2

MT

Mute activated

Optional

y3

MF

DTMF dialling mode selected

Optional

y4

LD

Loop disconnect (pulse) dialling mode selected

Optional

y5

Vol

Volume control keys activated. Remains on 2 seconds after last volume

key pressure

Always

y6

MR

Memory redial key has been pressed. Remains on until next key pressure

Always

y7

BO

Bell off. Indicates that ringer has been turn off.

Always

y8

SH

Shift; indicates that shift key has been pressed. Remains on untill next key

pressure

Optional

y9

-

Not used

Optional

y10

RD

Indicates that last number redial has been activated

Always

y11

PG

Indicates program mode

Symbol data are not effected by a BLINKING or by a WRITE&SHIFT command. Symbols will be displayed

independently from selecting the upper bank of the 32 digit buffer to be displayed.

The symbol displayed depends on the layout of the LCD display. If the layout of the 12/16 digit LCD displays can

be done similar, the symbol mapping does not need to be stored in the EEPROM.

Serial Interface

The serial interface uses the pins CS (chip select), SCLK (serial clock line), and DI (data input). A frame consists of

a 3-bit command and 5-bit data (see Figure 5: Frame of serial interface). Commands are executed self-timed by

the internal clock and commence at the falling edge of the CS signal.

CS

SCLK

DI

C3

C2

C1

D4

D3

D2

D1

D0

MSB

LSB

Figure 5: Frame of serial interface