HDSP-2301 HP [Agilent(Hewlett-Packard)], HDSP-2301 Datasheet - Page 25

• Manufacturer Part Number: HDSP-2301
• Description: Four Character 5.0 mm (0.20 inch) 5 x 7 Alphanumeric Displays
• Manufacturer: HP [Agilent(Hewlett-Packard)]

DATA OUT 74165,
Figure 11. Data Entry Timing for DECODED DATA CONTROLLER
Agilent Technologies under the
following part numbers:
HDSP-2470 – Controller with 64
HDSP-2471 – Controller with 128
HDSP-2472 – Controller with
All of the controllers have the
following features:
• Choice of character string
• Four modes of data entry
RAM ADDRESS
ADDRESS BUS
length: 4 to 48 characters in
increments of four characters
Left Entry
Right Entry
RAM Entry ( 32 characters
only)
Block Entry
74165 CLOCK
RAM DATA IN
RAM WRITE
DATA BUS
MEMWR
1
2
character ASCII to
5 x 7 decoder
character universal
ASCII to 5 x 7
decoder
socket for user
supplied custom
coded ROM/PROM/
EPROM.
ADDRESS BUS DECODING:
(001)(ADDR) (010)(ADDR)
ROW 7
ADDR = A 7 A 6 A 5 A 4 A 3 A 2 A 1 A 0
• Flashing Cursor – Left Entry
• Data Out ( 32 characters only)
These controllers have been de-
signed to eliminate the burden of
data handling between keyboard,
display, and microprocessor. The
product data sheet describes the
technical function of the control-
lers in detail.
Interfacing the controller to mi-
croprocessor systems depends on
the needs of the particular appli-
cation. Figure 19 depicts a latched
interface from a master micropro-
cessor to the HDSP-247X series of
controllers. These interfaces are
utilized to avoid having the master
processor wait for the controller
to accept data.
• Edit Functions
Only
ROW 6
Clear
Backspace
Forward Cursor
Insert
Delete
Display
Cursor
A 2
0
0
0
0
1
A 1
(011)(ADDR)
0
0
1
1
0
ROW 5
A 0
0
1
0
1
0
RIGHT
ENTRY
COL 1
COL 2
COL 3
COL 4
COL 5
(100)(ADDR)
ROW 4
LEFT
ENTRY
A 7
0
1
(101)(ADDR)
A 6
0
1
ROW 3
A 5
0
1
In sophisticated systems, it may
be desirable to have the
HDSP-247X controller handle all
of the keyboard/display interface
while the microprocessor reads
edited messages from the control-
ler DATA OUT port. This function
can be achieved through the use
of peripheral interface adapters
(PIA) available from the micro-
processor manufacturers. Figure
20 depicts a 6800 based system in
which data may enter the display
from either a keyboard or a
microprocessor. This interface
uses a 6821 PIA configured so that
PB
processor or keyboard enters data
into the controller. The 6800 pro-
gram is shown in Figure 21.
Subroutine “LOAD” uses CA
CA
shake that allows the 6800 to load
data into the controller as fast as
the controller can accept it. After
the prompting message has been
loaded, the microprocessor turns
the control of data entry over to
the keyboard. A signal from the
keyboard (“ER” in the example)
sets a flag within the 6821.
Depending on how the 6821 is
configured, the microprocessor
17
A 4
0
1
7
2
(110)(ADDR)
controls whether the micro-
to provide a data entry hand-
ROW 2
A 3
0
1
RIGHTMOST CHARACTER
LEFTMOST CHARACTER
(111)(ADDR)
ROW 1
AN1016.11
1
and