Analog Devices AD9833 Manual page 14

AD9833
YES
YES
V = V  18 R /R  (1 + (SIN(2(FREQREG
OUT REF LOAD SET
YES
CHANGE
FSELECT?
NO
CHANGE FREQUENCY
REGISTER?
YES
YES
CONTROL REGISTER
WRITE
(SEE TABLE XI)
Figure 7. Flow Chart for AD9833 Initialization and Operation
(CONTROL REGISTER WRITE)
WRITE TO FREQUENCY AND PHASE REGISTERS
FREQ0 REG = F
FREQ1 REG = F
PHASE0 AND PHASE1 REG = (PHASESHIFT  2
SELECT FREQUENCY REGISTERS
SELECT PHASE REGISTERS
(CONTROL REGISTER WRITE)
FSELECT = SELECTED FREQUENCY REGISTER
PSELECT = SELECTED PHASE REGISTER
Figure 8. Initialization
DATA WRITE
SEE FIGURE 9
SELECT DATA
SOURCES
WAIT 8/9 MCLK
CYCLES
DAC OUTPUT
f t

/2
MCLK 28
YES
CHANGE PHASE?
NO
CHANGE FREQUENCY?
NO
CHANGE DAC OUTPUT
FROM SIN TO RAMP?
NO
CHANGE OUTPUT TO
A DIGITAL SIGNAL?
NO
INITIALIZATION
APPLY RESET
RESET = 1
f
/  2
28
OUT0 MCLK
f
/  2
28
OUT1 MCLK
) / 2
12
(SEE FIGURE 9)
SET RESET = 0
RESET BIT = 0
–14–
INITIALIZATION
SEE FIGURE 8 BELOW
+ PHASEREG /2 ))))
12
YES
CHANGE
PSELECT?
NO
CHANGE PHASE
REGISTER?
YES
REV. A