HDSP-253 Datasheet, PDF (7/16 Pages) Agilent(Hewlett-Packard) – Eight Character 5 mm Smart Alphanumeric Display

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Electrical Description
Pin Function
Description
RESET (RST, pin 1)
Reset initializes the display.
FLASH (FL, pin 2)
ADDRESS INPUTS
(A₀-A₄, pins 3-6, 10)
FL low indicates an access to the Flash RAM and is unaffected by the
state of address lines A -A .
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Each location in memory has a distinct address. Address inputs (A₀-A₂)
select a specific location in the Character RAM, the Flash RAM or a
particular row in the UDC (User-Defined Character) RAM. A₃-A₄ are
used to select which section of memory is accessed. Table 1 shows the
logic levels needed to access each section of memory.
Table 1. Logic Levels to Access Memory
FL A₄ A₃ Section of Memory
0 X X Flash RAM
A₂ A₁ A₀
Character Address
1 0 0 UDC Address Register
Don’t Care
1 0 1 UDC RAM
Row Address
11 0
Control Word Register
Don’t Care
1 1 1 Character RAM
Character Address
CLOCK SELECT
(CLS, pin 11)
CLOCK INPUT/OUTPUT
(CLK, pin 12)
This input is used to select either an internal (CLS = 1) or external (CLS = 0)
clock source.
Outputs the master clock (CLS = 1) or inputs a clock (CLS = 0) for slave
displays.
WRITE (WR, pin 13)
CHIP ENABLE (CE, pin 14)
READ (RD, pin 19)
DATA Bus
(D₀-D₇, pins 20, 21, 25-30)
GND (SUPPLY) (pin 16)
GND (LOGIC) (pin 18)
V_DD (POWER) (pin 15)
Thermal Test (pin 17)
Data is written into the display when the WR input is low and the
CE input is low.
This input must be at a logic low to read or write data to the display and
must go high between each read and write cycle.
Data is read from the display when the RD input is low and the CE
input is low.
The Data bus is used to read from or write to the display.
This is the analog ground for the LED drivers.
This is the digital ground for internal logic.
This is the positive power supply input.
This pin is used to measure the IC junction temperature.
Do not connect.