HDSP-2107 Datasheet, PDF (9/16 Pages) Agilent(Hewlett-Packard) – Eight Character 5 mm and 7 mm Smart Alphanumeric Displays

9
Electrical Description
Pin Function
Description
RESET (RST, pin 1)
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 A₃-A₄.
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
Section of Memory
Flash RAM
FL
A₄
A₃ A₂ A₁ A₀
0
X
X Char. Address
UDC Address Register
1
0
0 Don't Care
UDC RAM
1
0
1 Row Address
Control Word Register
1
1
0 Don’t Care
Character RAM
1
1
1 Character Address
CLOCK SELECT
(CLS, pin 11)
CLOCK INPUT/OUTPUT
(CLK, pin 12)
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 17)
READ (RD, pin 18)
DATA Bus (D₀-D₇,
pins 19, 20, 23-28)
GND (SUPPLY) (pin 15)
GND (LOGIC) (pin 16)
V_DD (POWER) (pin 14)
Data is written into the display when the WR input is low and the
CE input is low.
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.
Used to read from or write to the display.
Analog ground for the LED drivers.
Digital ground for internal logic.
Positive power supply input.