ald523d Advanced Linear Devices Inc (ALD), ald523d Datasheet - Page 14

• Manufacturer Part Number: ald523d
• Description: Multifunction 7-digit Serial Input Display Module Controller
• Manufacturer: Advanced Linear Devices Inc (ALD)

DEFAULT PULL-UP AND PULL-DOWN
RESISTORS
Switches or jumpers can be used to interface the
ALD523D control-input pins directly to the desired logic
level, either V
KΩ pull-down resistors. This method of connection is
adopted as a default (standard) connection.
Figure 8 shows an example of standard connection where
a switch SW or a jumper is used to pull the display set
selection SEL1 control-input pin down to logic level “0”
through a 1-kΩ pull-down resistor to GND with the switch
SW closed. The SEL1 control-input pin is pulled up to
logic level “1” through a 15-kΩ pull-up resistor to V
the switch SW opened.
This method of connection allows both pull-up and pull-
down resistors to be installed simultaneously.
switch SW is closed, the pin is normally at a logical “0”
state, which sets SEL1=0. However, when ALD523D is
transferring data to the CDM, the same pin changes
function from SEL1 to D1, and the ALD523D output
overrides both the pull-up and pull-down resistors. All the
other multiplexed pins that interface to the CDM are
multiplexed in the same way.
ALD523D
ALD523D
© © © © 2001 Advanced Linear Devices, Inc., 415 Tasman Drive, Sunnyvale, California 94089-1706, Tel: [phone], Fax: [phone]
Figure 8. 15-kΩ Ω Ω Ω pull-up or 1-kΩ Ω Ω Ω pull-down resistor
U1
SEL1/D1
SEL0/D0
connection via SW switch.
20
19
+
R-PullUp = 15K
R-PullDown = 1K
or DGND, through 15-kΩ pull-up and 1-
12/01
R-PullDown
R-PullUp
SW
+V
LCD or VFD
+V
PMOS
NMOS
http://www.aldinc.com
When
+
with
CHARACTER DISPLAY MODULE
The ALD523D controller is designed for easy setting of
industry standard Character Display Modules (CDM) such
as 1 line by 16-character or 2-line by 16-character LCD or
VFD display modules. These Character Display Modules
consist of high contrast liquid crystal or vacuum
fluorescence panels.
Each module contains an industry standard controller such
as HD44780 or equivalent, and all necessary drivers. This
industry standard controller is equipped with an internal
Character Generator (CG ROM and CG RAM), Display
Data (DD RAM), and Column Driver such as LC7930N or
equivalent. ALD523D contains all the necessary display
function instructions of the CDM to fully display all the
characters on the display line(s), and to access all the
available alphanumeric characters within the CG ROM.
Standard font version of CGROM, European font version
of CGROM, or other custom versions of CGROM can be
used with ALD523D. For more information, consult with
the CDM manufacturer’s technical data.
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