AS2590P AMSCO [austriamicrosystems AG], AS2590P Datasheet - Page 4

• Manufacturer Part Number: AS2590P
• Description: LC DISPLAY DRIVER WITH 18 DIGITS, 6 SYMBOLS AND CLOCK/TIMER
• Manufacturer: AMSCO [austriamicrosystems AG]

Data Sheet
Description
Operating Modes
The following two operating modes are pin selectable:
Mode 0:
Clock and timer are disabled and the oscillator is stopped
when going on-hook (command BLANK ALL).
Mode 1:
Clock and timer functions are enabled, clock is displayed
both during off- and on-hook (assuming that clock is set).
When going from off-hook to on-hook, the timer content
(elepsed time) is displayed for 6 seconds (assuming that
a start timer command was received).
Clock
After a power up reset the clock is disabled. The clock
will not be displayed until a valid set clock procedure has
been performed (mode 1 only). The format of the clock
is hh:mm and the leading zero of the hours is suppressed
and symbol 5 (:) is blinking with a frequency of 1 Hz. The
timer is running when off-hook and displayed for 6
seconds when going on-hook. The content of the timer
(elapsed time) is shown in stead of the clock in the format
mm:ss.
If a SET CLOCK command is received the display is
blanked, four underscore symbols are displayed where
the 4 digits of the clock will be entered (the 4 most right
digits) and symbol 5 is turned on (_ _ : _ _). The next 4
data words are interpreted as the time (hh mm). The
fourth digit terminates the SET CLOCK and starts the
clock with the seconds set to zero.
If less than 4 data words (digits) are received the first
command (normally a BLANK DIGITS or a BLANK ALL)
will terminate the SET CLOCK. But as the procedure
was incomplete, it is regarded as invalid and further
clock display is disabled. The next valid SET CLOCK
command will enable the clock again. The SET CLOCK
command does not effect the timer.
The time-out condition (approx. 15 seconds) when setting
clock is recognized by the dialler/controller (e.g. AS2574).
If a time-out condition occours the dialler sends a
BLANK ALL command to terminated the SET CLOCK.
Timer
The following commands effect the timer:
- START TIMER and START FIFO; they start the timer.
Rev. 1
If the timer is already running, it cannot be restarted
by one of these commands before stopping the timer
with the BLANK ALL command.
4
- Power up; enables subsequent start timer commands.
- BLANK ALL; clears the whole display (including special
- if any command or data is received by the serial
The timer is displayed in the format mm:ss with the
leading zero of the minutes suppressed and symbol 5 (:)
turned on.
LCD Outputs
The 33 segment outputs and 4 backplane outputs can
drive a customized liquid crystal display in 1:4 multiplex
mode. Two reference voltages V1/3 and V2/3 are
provided by an external voltage divider.
Digits and Special Symbols
The display consists of 18 seven segment digits and 6
special symbols (see figure 1):
- D0…D17; D0 is the most left seven segment digit, the
- SB0…SB5; 6 special symbols (one segment for each
Multiplex Mode
A total of 132 segments are addressable. One output
drives 4 segments in a time multiplex mode. The 4
backplane outputs determine the currently addressed
segment (see figure 3).
Figure 3 gives the correlation between segment outputs
and addressed segments.
Data and Commands
32 different words may be received via the serial interface.
19 words are interpreted as display data for one of the
18 seven segment digits. Table 2 gives the translation
from received code to displayed symbol.
13 words are valid commands codes. The function of
each command is described in table 2, and table 4 lists
the 5 bit codes for all possible commands.
symbols) and displays the timer contents for 6 seconds
(if clock/timer function is enabled) or until a new
START TIMER/FIFO command is received. Then it
returns to normal display mode.
interface within the time out period after a BLANK ALL
command, the timer display will be blanked or replaced
by the clock display.
possible numbers displayed by one digit are shown in
figure 2. The symbol (_) is only displayed at D13, D14,
D16 and D17 when setting the clock.
symbol only), see figure 1 for reference. If SB0
(loudspeaker on) or SB1 (microphone muted) are
turned on, they blink with a frequency of 1 Hz.
AS2590
Dec. 1993