AD9834
INITIALIZATION
APPLY RESET
USING PIN
USING CONTROL
BIT
(CONTROL REGISTER WRITE)
(CONTROL REGISTER WRITE)
PIN/SW = 1
SET RESET PIN = 1
RESET = 1
PIN/SW = 0
WRITE TO FREQUENCY AND PHASE REGISTERS
28
FREQ0 REG = f
FREQ1 REG = f
PHASE0 AND PHASE1 REG = (PHASESHIFT × 2 )/2π
/f
× 2
× 2
OUT0 MCLK
28
/f
OUT1 MCLK
12
(SEE FIGURE 33)
SET RESET = 0
SELECT FREQUENCY REGISTERS
SELECT PHASE REGISTERS
USING CONTROL
USING PIN
BIT
(CONTROL REGISTER WRITE)
(APPLY SIGNALS AT PINS)
RESET PIN = 0
FSELECT = SELECTED FREQUENCY REGISTER
PSELECT = SELECTED PHASE REGISTER
RESET BIT = 0
FSEL = SELECTED FREQUENCY REGISTER
PSEL = SELECTED PHASE REGISTER
PIN/SW = 0
Figure 32. Initialization
DATA WRITE
NO
NO
WRITE 14 MSBs OR LSBs
TO A FREQUENCY REGISTER?
WRITE A FULL 28-BIT WORD
TO A FREQUENCY REGISTER?
WRITE TO PHASE
REGISTER?
YES
YES
YES
(CONTROL REGISTER WRITE)
B28 (D13) = 0
(CONTROL REGISTER WRITE)
B28 (D13) = 1
HLB (D12) = 0/1
(16-BIT WRITE)
D15, D14 = 11
D13 = 0/1 (CHOOSE THE
WRITE A 16-BIT WORD
PHASE REGISTER)
WRITE TWO CONSECUTIVE
16-BIT WORDS
D12 = X
D11 ... D0 = PHASE DATA
(SEE TABLES 12 AND 13
FOR EXAMPLES)
(SEE TABLE 11 FOR EXAMPLE)
WRITE 14 MSBs OR LSBs
TO A
FREQUENCY REGISTER?
WRITE TO ANOTHER
PHASE REGISTER?
WRITE ANOTHER FULL
28-BIT TO A
FREQUENCY REGISTER?
YES
YES
YES
NO
NO
NO
Figure 33. Data Write
Rev. C | Page 24 of 36
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