HDSP-2301 HP [Agilent(Hewlett-Packard)], HDSP-2301 Datasheet - Page 19

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

Figure 6. 6800 Microprocessor Program Utilizing a 160 Byte RAM Buffer that Interfaces to the REFRESH CONTROLLER
(cont.)
CDVR
TURN OFF COLUMN DRIVERS
RDVR
STORE FIRST BYTE DECODED DATA IN 74165
RDVR
STORE SECOND BYTE DECODED
DATA IN 74165
RDVR
STORE 32nd BYTE DECODED DATA IN 74165
CDVR
TURN ON APPROPRIATE COLUMN DRIVER
POINT
UPDATE POINT WITH ADDRESS OF DECODED
DATA FOR NEXT COLUMN TO BE REFRESHED
COLUMN
UPDATE COLMN FOR NEXT REFRESH CYCLE
FF
(POINT)
(POINT + 1)
(POINT + 31)
COLMN
POINT + 32
H
2 COLMN + 1
REFRESHED
COLUMN 5?
NO
RETURN
RFRSH
JUST
•
•
•
(LOOP B)
POINT
UPDATE POINT WITH ADDRESS
OF COLUMN 1 IN DECODED
DATA RAM
COUNT
OPTIONAL 2 ms TIMER
COLMN
UPDATE COLMN TO TURN
ON COLUMN 1
YES
BUFFER
COUNT –1
FE
RETURN
H
DISPNT
UPDATE DISPNT WITH ADDRESS OF NEXT BYTE IN DECODED DATA RAM
ASCII
INITIALIZE ASCII WITH ADDRESS OF RIGHTMOST ASCII SYMBOL
PLUS ONE
ASCII
UPDATE ASCII WITH ADDRESS OF NEXT SYMBOL TO LEFT
DISPNT
STORE BYTE OF DECODED DATA IN DECODED DATA RAM
B
ADD OFFSET FOR NEXT COLUMN IN DECODER ROM
DISPNT
LOAD DISPNT WITH ADDRESS OF DECODED DATA RAM
DCRPNT
LOAD DCRPNT WITH ADDRESS OF DECODER ROM
DCRPNT
ACCESS BYTE OF DECODED DATA FROM DECODER
DISPNT + 1
B + 80
ASCII + 32
ASCII –1
B
INITIALIZE COLUMN OFFSET = 0
(DCRPNT)
H
0
BUFFER
DECDR
(ASCII) + B + DECDR
COLCNT
DIGCNT
DIGCNT
COLCNT
YES
YES
RETURN
COLCNT
DIGCNT
11
LOAD
= 0?
= 0?
DIGCNT –1
COLCNT –1
32
5
(LOOP 3)
(LOOP 1)
NO
NO