AD664 Analog Devices, AD664 Datasheet - Page 17

• Manufacturer Part Number: AD664
• Description: Monolithic 12-Bit Quad DAC
• Manufacturer: Analog Devices

Specifications of AD664

• Resolution (bits): 12bit
• Dac Update Rate: 125kSPS
• Dac Settling Time: 8µs
• Max Pos Supply (v): +16.5V
• Single-supply: No
• Dac Type: Voltage Out
• Dac Input Format: Byte,Nibble,Par

REV.
The following IBM PC Basic routine produces four output volt-
age ramps from one AD664. Line numbers 10 through 70 de-
fine the hardware addresses for the first and second ranks of
DAC registers as well as the first and second ranks of the mode
select register. Program variables are initialized in line numbers
110 through 130. Line number 170 writes “0s” out to the first
rank and, then, the second rank of the mode select register.
D
5
10
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100
110
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130
140
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170
180
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200
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400
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510
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530
REM----AD664 LISSAJOUS PATTERNS----
REM ---ASSIGN HARDWARE ADDRESSES---
DACA = 785
DACB = 787
DACC = 789
DACD = 791
DAC2ND = 792
MODE1 = 769: MODE2 = 776
REM
REM
REM ---INITIALIZE VARIABLES---
X = 0: Y1 = 128: Y2 = 64: Y3 = 32
CX = 1: CY1 = 1: CY2 = -1: CY3= 1
FX = 9: FY1 = 5: FY2 = 13: FY3 = 15
REM
REM
REM ---INITIALIZE MODES AND GAINS---
OUT MODE1,0: OUT MODE2,0
REM
REM
REM ---CALCULATE VARIABLES---
X = X + FX*CX
Y1 = Y1 + FY1*CY1
Y2 = Y2 + FY2*CY2
Y3 = Y3 + FY3*CY3
IF X > 255 THEN X = 255: CX = -1: GOTO 270
IF X < 0 THEN X = 0: CX = 1
IF Y1 > 255 THEN Y1 = 255: CY1 = -1: GOTO 290
IF Y1 < 0 THEN Y1 = 0: CY1 = 1
IF Y2 > 255 THEN Y2 = 255: CY2 = -1 GOTO 310
IF Y2 < 0 THEN Y2 = 0: CY2 = -1
IF Y3 > 255 THEN Y3 = 255: CY3 = -1: GOTO 400
IF Y3 < 0 THEN Y3 = 0: CY3 = 1
REM
REM
REM ---SEND DAC DATA---
OUT DACA,X
OUT DACB,Yl
OUT DACC,Y2
OUT DACD,Y3
OUT DAC2ND,0
REM
REM
REM ---LOOP BACK---
GOTO 210
–17–
Line numbers 200 through 320 calculate output voltages. Fi-
nally line numbers 410 through 450 update the first, then the
second ranks of the DAC input registers. Hardware registers
may be read with the “INP” instruction. For example, the con-
tents of the DAC A register may be accessed with the following
com mand: Line# A = INP(DACA).
AD664