9
0 = Logic 0; 1 = Logic 1; X = Do Not Care
Figure 2. Display truth table.
Display Clear
Data stored in the Character RAM, Control Register, and
Attribute RAM will be cleared if the clear (CLR) is held
low for a minimum of 10 μs. Note that the display will be
cleared regardless of the state of the chip enables (CE
1
,
CE
2
). After the display is cleared, the ASCII code for a space
(20hex) is loaded into all character RAM locations and
00hex is loaded into all Attribute RAM/Control Register
memory locations.
Data Entry
Figure 2 shows a truth table for the HDLX-3416 display.
Setting the chip enables (CE
1
, CE
2
) to logic 0 and the cursor
select (CU) to logic 1 will enable ASCII data loading. When
cursor select (CU) is set to logic 0, data will be loaded into
the Control Register and Attribute RAM. Address inputs
A
0
-A
1
are used to select the digit location in the display.
Data inputs D
0
-D
6
are used to load information into the
display. Data will be latched into the display on the rising
edge of the WR signal. D
0
-D
6
, A
0
-A
1
, CE
1
, CE
2
, and CU
must be held stable during the write cycle to ensure that
correct data is stored into the display. Data can be loaded
into the display in any order. Note that when A
0
and A
1
are
logic 0, data is stored in the right most display location.
Cursor
When cursor enable (CUE) is a logic 1, a cursor will be
displayed in all digit locations where a logic 1 has been
stored in the Digit Cursor memory in the Attribute RAM.
The cursor consists of all 35 dots ON at half brightness. A
ashing cursor can be displayed by pulsing CUE. When
CUE is a logic 0, the ASCII data stored in the Character RAM
will be dis played regardless of the Digit Cursor bits.
Blanking
Blanking of the display is con trolled through the BL input,
the Control Register, and Attribute RAM. The user can
achieve a variety of functions by using these controls
in di erent combinations, such as full hardware display
blank, software blank, blanking of individual characters,
and syn chronized ashing of individual characters or
entire display (by strobing the blank input). All of these
blanking modes a ect only the output drivers, maintain-
ing the contents and write capability of the internal RAMs
and Control Register, so that normal loading of RAMs and
Control Register can take place even with the display
blanked.
CUE BL CLR CE
1
CE
2
WR CU A
1
A
0
D
6
D
5
D
4
D
3
D
2
D
1
D
0
Function
0 1 1 Display ASCII
1 1 1 Display Stored Cursor
X X 0
X X X X X X X X X X X X X
Reset RAMs
X 0 1
Blank Display but do not reset
RAMs and Control Register
Extended Intensity Master Digit Digit Write to Attribute RAM
0 0 0 Functions Control Blank Blank Cursor and Control Register
Disable Disable 0 0
0 = 000 = 100% 0 = Digit Digit DBDn = 0, Allows Digit n to be
0 0 1 Enable 001 = 60% Display Blank Cursor blanked
D
1
-D
5
010 = 40% ON Disable 1 1
011 = 27% DBDn = 1 Prevents Digit n from
X X 1 0 0 0 1 = 100 = 17% 1 = Digit Digit being blanked.
0 1 0 Disable 101 = 10% Display Blank Cursor
D
1
-D
5
110 = 7% Blanked Disable 2 2 DCn = 0 Removes cursor from
111 = 3% Digit n
D
0
Digit Digit
0 1 1 Always Blank Cursor DCn = 1 Stores cursor at
Enabled Disable 3 3 Digit n
1 0 0 Digit 0 ASCII Data (Right Most Character)
X X 1 0 0 0 1 0 1 Digit 1 ASCII Data Write to Character RAM
1 1 0 Digit 2 ASCII Data
1 1 1 Digit 3 ASCII Data (Left Most Character)
1 X X
X X 1 X 1 X X X X X X X X X X X No Change
X X 1
