ald523d Advanced Linear Devices Inc (ALD), ald523d Datasheet - Page 3

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

GENERAL DESCRIPTION
The ALD523D is a Multifunction 7-Digit Serial Input
Display Module Controller designed to interface directly
to ALD500 or ALD500R integrating dual slope precision
analog processors as a chip set for building a high
precision and high accuracy analog-to-digital converter
system with auto zero and auto-polarity. The ALD523D
also functions as an universal serial input 7-digit display
module controller that interfaces to most popular industry
standard serial data formats from other microprocessors or
data converters. It 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. The ALD523D is an enhanced version of
the ALD521D digital controller. The ALD523D functions
in three separate operating modes, namely calibrated
reference (mode-A), ratiometric (mode-B), and display
only (mode-C).
The ALD523D digital controller operates as a master
display module controller in either a stand-alone mode or
in an external microprocessor control mode. In the external
microprocessor control mode, the ALD523D can directly
interface with a PC under PC software control via a
standard parallel printer port. This external control mode
is managed by the Serial I/O Interface Logic inside the
ALD523D.
In the stand-alone mode, the ALD523D makes continuous
measurements, and includes all the necessary functions to
fully control a CDM. In the stand-alone mode, ALD523D
operates in conjunction with a 1K EEPROM chip to
preserve the setup parameters and arithmetic (calibration)
parameters of the ALD523D.
The setup and arithmetic parameters are uploaded to the
EEPROM via ALD523D Setup and Calibration PC
software (DVM523). The ALD523D communicates to the
EEPROM on a handshake protocol governed by the
EEPROM Memory Controller inside the ALD523D.
The ALD500/ALD500R dual slope precision analog
processors consist of on-chip digital control circuitry to
accept control inputs, integrating buffer amplifiers, analog
switches, and voltage comparators. It functions in four
operating phases, namely auto zero, integrate, de-integrate,
and integrator zero phases. At the end of a conversion, the
comparator output goes from high to low when the
integrator
ALD500/ALD500R
processors also provide direct logic interface to
ALD523D.
ALD523D
© © © © 2001 Advanced Linear Devices, Inc., 415 Tasman Drive, Sunnyvale, California 94089-1706, Tel: [phone], Fax: [phone]
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12/01
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de-integration.
http://www.aldinc.com
analog
The ALD523D implements the logic and timing for all the
four phases of the ALD500/ALD500R, namely auto zero,
integrate, de-integrate, and integrator zero phases in mode-
A and mode-B operations.
governed by the Dual Slope A/D 4-Phase Controller inside
the ALD523D. The ALD523D operates from an external
clock or its internal oscillator circuit along with an external
crystal. The internal system clock of the ALD523D runs
at a frequency which can be selected at divide-by N (4, 8,
or 64) rate of the crystal (or external) clock frequency.
The ALD523D offers up to 3 display settings, known as
display sets, namely “DGS1”, “DGS2” and “DGS3”.
“DGS1” also has an optional hardware decimal point
setting mode, known as “DGS0”, which allows the user to
use hardware jumper switches to set decimal point
position. Each display set allows a full 7-digit decimal
number to be converted from a 16-bit to 32-bit serial
binary number using the Serial Binary To 6½-Digit
Decimal Converter inside the ALD523D. This 6½-digit
decimal number can also be scaled by a MULTIPLIER
number, and the result of the scaled number displayed on
the CDM through the Display Module Controller within
the ALD523D. Additional display parameters that can be
manipulated are: Digit Blanking, which allows user
selection of number of digits to display; Decimal Point
placement, which controls placement of decimal point, if
any. Up to 3 sets of display UNIT fields are available,
each with a combination of alphanumeric characters up to
8 characters long.
The ALD523D also features hardware control-input pins
for power down (PWRCS), integration time selection (S1,
S2 and S3), data sample averaging (DSA1 and DSA2),
digit blanking (B1 and B2), decimal point placement
(DEC1 and DEC2), zero offset (M and Z), and display set
selection (SEL0 and SEL1). When not used, or if no
control is desired, each of these optional pins are wired to
their respective desired logic state, either V
(DGND), through pull-up or pull-down resistors.
functions of the control-input pins are managed by the
Control Logic section in the ALD523D.
MODES OF OPERATIONS
The ALD523D functions in either single operating mode
or multiple operating modes, namely calibrated reference
(mode-A), ratiometric (mode-B), and display only (mode-
C). In the single operating mode, ALD523D operates in
one of the three modes of operation, either mode-A, mode-
B or mode-C.
ALD523D can operate interchangeably in each of the three
In the multiple operating modes, the
These four phases are
+
or Ground
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The